Targeting TRIP13 in favorable histology Wilms tumor with nuclear export inhibitors synergizes with doxorubicin

Wilms tumor (WT) is the most common renal malignancy of childhood. Despite improvements in the overall survival, relapse occurs in ~15% of patients with favorable histology WT (FHWT). Half of these patients will succumb to their disease. Identifying novel targeted therapies remains challenging in part due to the lack of faithful preclinical in vitro models. Here we establish twelve patient-derived WT cell lines and demonstrate that these models faithfully recapitulate WT biology using genomic and transcriptomic techniques. We then perform loss-of-function screens to identify the nuclear export gene, XPO1, as a vulnerability. We find that the FDA approved XPO1 inhibitor, KPT-330, suppresses TRIP13 expression, which is required for survival. We further identify synergy between KPT-330 and doxorubicin, a chemotherapy used in high-risk FHWT. Taken together, we identify XPO1 inhibition with KPT-330 as a potential therapeutic option to treat FHWTs and in combination with doxorubicin, leads to durable remissions in vivo.

Impact on Radiation Therapy Recommendation and Treatment Modality for Patients with Ductal Carcinoma In Situ Using the 7Gene Biosignature: Analysis of the PREDICT Study

PURPOSE/OBJECTIVE(S)

Breast conserving surgery (BCS) followed by adjuvant radiotherapy (RT) has been a mainstay in the treatment of DCIS based on multiple randomized trials demonstrating a local recurrence benefit with RT. However, these studies have failed to identify subsets of patients who did or did not benefit from adjuvant RT after BCS, raising concerns regarding both over and undertreatment. Thus, better prognostic and predictive tools are needed to appropriately risk stratify patients and understand their benefit of RT. The 7-gene predictive DCIS biosignature provides a validated score (DS) for women undergoing BCS that assesses their 10-year risk of in-breast and invasive recurrence with and without adjuvant RT. This trail was designed to evaluate the decision impact of the 7-gene predictive biosignature score on DCIS treatment recommendations.

MATERIALS/METHODS

The PREDICT study is a prospective, multi-institutional trial for patients who received DCISionRT testing as part of their routine care. The registry includes females 26 and older who are diagnosed with DCIS, are candidates for BCS, and eligible for RT. Treating physicians completed treatment recommendation forms before and after receiving test reports to capture surgical, radiation and hormonal treatment (HT) recommendations and patient preferences. Analysis was performed in 2,012 patients treated at 63 clinical sites.

RESULTS

Median age was 62 years old with 32% grade 3 and 10% size 2.5 cm or greater. Post-test, RT recommendation changed for 38% of patients (p<0.001), with a net reduction of 20% in patients recommended to receive RT(p<0.001). The DCISionRT test results had the greatest impact (OR 26.2, 95% CI 19.1-36.4, when analyzed categorically using DS>3 cut-off; 2.3 per DS, 95% CI 2.1-2.6, when evaluated continuously) on post-test RT recommendation in multivariable analysis when compared to all other factors including patient preference, patient clinical and tumor pathological factors, patient race/ethnicity, treatment facility, physician specialty. The post-test RT recommendation rate increased with increasing DS (0-2, 2-4, 4-10) on a categorical basis, with odds ratios of 6.8 DS (2-4 vs 0-2), and 35.0 for DS (4-10 vs 0-2). After DCISionRT test result, patient preference was the second most important factor in post-testing RT recommendation. There was also a significant change in the modality of RT recommended to 34% of those patients recommended RT pre-test and post-test by radiation oncologists (n = 937), with intensified RT modality for higher DS (p<0.001) and de-escalation for lower DS (p<0.001).

CONCLUSION

This analysis of over 2,000 patients demonstrates significant changes in recommendations to add or omit RT based on the 7-gene predictive. The integration of DCISionRT into clinical decision processes has substantial impact on recommendations aimed at optimal management to prevent over- or under-treatment.

Limitations in the Application of Clinicopathologic Factors Alone in Predicting Radiation Benefit for Women with Low-Risk DCIS after Breast Conserving Surgery: The Impact of a 7-Gene Biosignature Based on 10-Year Ipsilateral Breast Recurrence (IBR) Rates

PURPOSE/OBJECTIVE(S)

Most women diagnosed with ductal carcinoma in situ (DCIS) receive radiotherapy (RT) after breast conserving surgery (BCS); however, clinical trials show that over 70% of women with BCS alone will not have a recurrence and therefore not benefit from RT. Traditionally, clinicopathologic (CP) factors have been used to select for whom to de-escalate treatment, but prospective trials have failed to identify a low risk CP group that did not benefit from RT with respect to local control. This study assessed the re-classification of patients with low-risk CP into Risk groups defined by the 7-gene biosignature and compared to 10-yr IBR rates.

MATERIALS/METHODS

Women (n = 926) from four international DCIS cohorts treated with BCS had formalin-fixed paraffin embedded tissue samples analyzed at a CLIA lab (Laguna Hills, CA). CP low-risk patients were identified using a) RTOG-9804-like criteria [Nuclear Grade 1 or 2 & Size ≤2.5 cm & non-Palpable & Screen Detected & margin negative (no-ink on tumor)] and b) MSKCC-like criteria [low-risk score<220, determined using nomogram weighted factors (excluding: number of re-excisions and RT treatment), and using no-ink-on-tumor instead of close margin]. The 7-gene DCIS biosignature combined biomarkers with CP factors (age, size, palpability, and margin status) using an algorithm reporting a Decision Score (DS) and Residual Risk subtype (RRt). Women with low-risk CP were classified into biosignature Low Risk (DS≤2.8, no RRt) or High Risk (DS>2.8 +/- RRt) groups. 10yr in-breast event (IBR) rates with and without RT were assessed by Kaplan-Meier rates and Cox proportional hazard analyses.

RESULTS

Overall, 37% of all women were classified into the biosignature Low Risk group, while 51% and 34% were classified into CP low-risk groups (RTOG-9804-like, MSKCC-like, respectively). The biosignature Low Risk group (n = 338) had a 10-yr IBR risk of 5.6% after BCS and no significant RT benefit (absolute RT benefit = 0.8%, p = 0.70), 99% negative predictive value (NPV) for RT benefit. CP low-risk groups had 10-yr IBR rates of 12% and 8% after BCS without RT with absolute 6% (p = 0.04) and 4% (p = 0.1) IBR rate reductions with RT. The biosignature reclassified 51% and 63% of CP low-risk patients into the biosignature High Risk group. Importantly, these patients had higher IBR rates without RT (20% and 12%) and significant 13% (p = 0.005) and 8% (p = 0.01) absolute IBR rate reductions from RT. CP low-risk patients with concordant biosignature Low Risk demonstrated no significant RT benefit.

CONCLUSION

The 7-gene predictive biosignature more reliably identified patients with low 10-yr IBR rates and no significant RT benefit than the traditional CP low-risk criteria (RTOG-9804-like, MSKCC-like). Importantly, those CP low-risk patients who were re-classified as biosignature High Risk had increased 10-year IBR rates and significant RT benefit.

A Biosignature Integrating Immune and Metabolic Signaling Axes to Assess Limited Radiation Therapy Response in Early-Stage Breast Cancer from a Low-Risk Cohort

PURPOSE/OBJECTIVE(S)

Radiation therapy (RT) post breast conserving surgery (BCS) reduces in-breast recurrence (IBR) rate in early-stage invasive breast cancer (BC) patients. The RT treatment recommendation is often driven by clinicopathological (CP) factors; however, CP factors alone have limited ability to identify which women significantly benefit from RT, or those with higher IBR risk after BCS plus RT. Biologic factors driving unique phenotypes, in addition to CP, may improve prediction of RT response. In this study we evaluated the role of immune and metabolic signaling axes in predicting RT response in hormone receptor positive, HER2 negative, early-stage BC patients.

MATERIALS/METHODS

Biomarkers from immune and metabolic signaling axes were studied in a cohort of 939 women from Sweden, at a CLIA certified lab (Laguna Hills, CA). Formalin fixed paraffin embedded tissues were assayed for protein expression using multiplex immunofluorescence and multi-spectral imaging. Immune and metabolic axes were assessed using biomarkers combined with a non-linear model, adjusting for patient age. RT prediction by the model was assessed, along and adjusted for CP factors and also among patients over 50-yrs. The model defined patient risk groups that were analyzed for IBR rate using Kaplan Meier analyses and Cox proportional hazards to test for RT-risk group interaction.

RESULTS

Within the cohort, 440 patients had hormone receptor positive, HER2 negative BC treated with BCS (negative margins) and +/- RT without chemotherapy, where 296 patients had complete biomarker data. CP factors individually were not predictive for RT benefit, but grade was prognostic for IBR rate (p = 0.02) after BCS without RT. In multivariable analysis, adjusting for CP factors (grade, palpability, continuous size and age), the model was predictive for RT benefit (p-interaction = 0.046), identifying patients (n = 129) with worse RT benefit (HR = 7.8) compared to baseline RT benefit. The model was not prognostic for IBR rate in patients treated with BCS without RT (16% 10-yr IBR rate) but identified patients with increased IBR rates after BCS plus RT (HR = 3.9, p<0.001), where corresponding 10-yr IBR rates increased from 3% to 15%. The model was also predictive for RT benefit in women over 50-yrs (p-interaction = 0.05). The model identified 28% of women over 50-yrs who had increased IBR rates after BCS plus RT (HR = 4.0, p = 0.004), where corresponding 10-yr IBR rates increased from 3% to 12%.

CONCLUSION

The model incorporating metabolic and immune signaling axes assessed in the study was predictive for RT benefit among women with early-stage hormone receptor positive, HER2 negative BC. While CP factors were not predictive of RT benefit, the inclusion of metabolic and immune signaling axes improved identification of patients with high residual risk after BCS plus RT and can potentially aid in personalized treatment of early-stage breast cancer based on individualized risk.

Analytical validation of the 7-gene biosignature for prediction of recurrence risk and radiation therapy benefit for breast ductal carcinoma in situ

Purpose

Ductal carcinoma in situ (DCIS), is a noninvasive breast cancer, representing 20-25% of breast cancer diagnoses in the USA. Current treatment options for DCIS include mastectomy or breast-conserving surgery (BCS) with or without radiation therapy (RT), but optimal risk-adjusted treatment selection remains a challenge. Findings from past and recent clinical trials have failed to identify a 'low risk' group of patients who do not benefit significantly from RT after BCS. To address this unmet need, a DCIS biosignature, DCISionRT (PreludeDx, Laguna Hills, CA), was developed and validated in multiple cohorts. DCISionRT is a molecular assay with an algorithm reporting a recurrence risk score for patients diagnosed with DCIS intended to guide DCIS treatment. In this study, we present results from analytical validity, performance assessment, and clinical performance validation and clinical utility for the DCISionRT test comprised of multianalyte assays with algorithmic analysis.

Methods

The analytical validation of each molecular assay was performed based on the Clinical and Laboratory Standards Institute (CLSI) guidelines Quality Assurance for Design Control and Implementation of Immunohistochemistry Assays and the College of American Pathologists/American Society of Clinical Oncology (CAP/ASCO) recommendations for analytic validation of immunohistochemical assays.

Results

The analytic validation showed that the molecular assays that are part of DCISionRT test have high sensitivity, specificity, and accuracy/reproducibility (≥95%). The analytic precision of the molecular assays under controlled non-standard conditions had a total standard deviation of 6.6 (100-point scale), where the analytic variables (Lot, Machine, Run) each contributed <1% of the total variance. Additionally, the precision in the DCISionRT test result (DS) had a 95%CI ≤0.4 DS units under controlled non-standard conditions (Day, Lot, and Machine) for molecular assays over a wide range of clinicopathologic factor values. Clinical validation showed that the test identified 37% of patients in a low-risk group with a 10-year invasive IBR rate of ~3% and an absolute risk reduction (ARR) from RT of 1% (number needed to treat, NNT=100), while remaining patients with higher DS scores (elevated-risk) had an ARR for RT of 9% (NNT=11) and 96% clinical sensitivity for RT benefit.

Conclusion

The analytical performance of the PreludeDx DCISionRT molecular assays was high in representative formalin-fixed, paraffin-embedded breast tumor specimens. The DCISionRT test has been analytically validated and has been clinically validated in multiple peer-reviewed published studies.

Abstract OT3-11-03: The PREDICT Registry Australia: A prospective registry to evaluate the clinical utility of a 7-gene predictive biosignature on treatment decisions in patients with ductal carcinoma in situ

Background: For women with ductal carcinoma in situ (DCIS) treated with breast conserving surgery (BCS), the benefit of adjuvant radiation therapy (RT) remains controversial. Since there is level 1 evidence supporting the role of RT in reducing the risk of local recurrence, current guidelines generally recommend RT for all women having BCS even though the absolute benefit is variable. In response to the need for prognostic and predictive tools to better assess risk and RT benefit, a 7-gene predictive biosignature (DCISionRT, PreludeDx, Laguna Hills, CA) was developed. The test provides a validated score (DS) for assessing 10-year risk of recurrence and RT benefit using individual tumor biology, as assessed by clinical and pathologic biomarkers. The primary objective of the PREDICT registries is to understand the decision impact such a tool has on treatment decisions. Prospective Clinical Trial Design: This is a multicenter, prospective, observational registry for women diagnosed with DCIS in Australia. After DCIS diagnosis, sites will send the most representative tissue block or sections mounted on charged slides to the PreludeDx lab for biosignature testing. Treating physicians will complete a treatment recommendation survey before and after receiving the biosignature test results. Test results, treatment recommendations, patient preferences and clinicopathologic features will be stored in a de-identified registry for participating institutions from a variety of geographic regions across Australia. Women will then be followed for up to 10 years with completion of a follow-up form. The study has been approved by the North Shore Local Health District Human Research Ethics Committee, St Leonards, NSW, Australia. Universal Trial Number (UTN): U1111-1266-0439; ANZCTR: ACTRN12621000695808; ClinicalTrials.gov: NCT04916808. Eligibility Criteria: The study includes females age 26 or older who are candidates for BCS and eligible for RT and/or systemic treatment. Subjects must not have been previously treated for DCIS or have previous or current invasive or micro-invasive breast cancer. Specific Aims: The primary endpoints are changes in treatment recommendations for surgical, radiation and hormonal therapy. Secondary endpoints are identification of key drivers for treatment recommendations, including age, size, grade, necrosis, hormone receptor status, patient preference and biosignature status. Statistical Methods: Changes in pre- and post-DCISionRT treatment recommendations will be analyzed using McNemar’s test (alpha level = 0.05). Multivariate logistic regression will be used to determine odds ratios of clinicopathologic factors leading to pre- and post-test treatment recommendations. Pre-test covariates include patient age, tumor size, palpability, margin status, hormone receptor status, nuclear grade, tumor necrosis, family history of breast cancer, race, ethnicity and patient preference, as well as physician specialty (surgeons vs. radiation oncologists) and post-test covariates will also include the DCISionRT Decision Score (DS). Differences in recurrence-free and overall survival will be assessed by Kaplan-Meier survival analysis using the log-rank test and/or the Cox Proportional Hazards model. Statistical analyses will be carried out using R (https://www.r-project.org) or SAS. An early interim analysis based on the first 200 enrolled patients is currently underway. Present and Planned Accrual: We are planning to enroll up to 1,500 women from up to 100 sites across Australia. A similar registry has recently completed enrollment of 2,500 women from 68 sites in the US.

Citation Format: Yvonne Zissiadis, G Bruce Mann, David Speakman, Christobel Saunders, Christopher Pyke, Daniel De Viana, Melissa Bochner, James R. French, Marcus Dreosti, Sally Baron-Hay, Alexandra Feetham, Kim Kirkham, Shane Ryan, Karuna Mittal, Steven C. Shivers, Troy Bremer. The PREDICT Registry Australia: A prospective registry to evaluate the clinical utility of a 7-gene predictive biosignature on treatment decisions in patients with ductal carcinoma in situ [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-11-03.

Abstract P1-04-06: Characterization of recurrence risk after lumpectomy and radiotherapy in HER2-positive ductal carcinoma in situ of the breast, using 7-gene predictive biosignature: Implications for the NSABP-B43 trial results

Background: HER2-positive versus HER2-negative ductal carcinoma in situ (DCIS) of the breast has been associated with an increased risk of local recurrence after breast-conserving surgery (BCS) and radiotherapy (RT). In recognition of this, the NASBP-B43 trial was designed to determine if two doses of trastuzumab would improve local control with BCS plus RT in HER2-positive DCIS. The trial demonstrated a non-statistically significant advantage with the addition of trastuzumab in reducing ipsilateral breast recurrence (IBR). The predictive 7-gene DCIS biosignature, DCISionRT with Residual Risk Subtype (PreludeDxTM, Laguna Hills, CA) has been shown to classify DCIS patients into two distinct groups of patients with substantially different rates of IBR following BCS plus RT. Based upon these differences in outcome, we assessed the IBR rate in patients with HER2(+) DCIS treated with BCS and RT who were or were not in the Residual Risk Subtype group defined using DCISionRT, while accounting for the varying clinicopathologic profile of the patients.

Materials & Methods: DCISionRT was evaluated in a subset of 178 women with HER2(+) DCIS treated with BCS and RT as part of a multinational cohort of 926 patients from the United States, Sweden, and Australia, who were used in the validation studies for DCISionRT. Central pathology review and biosignature testing were performed at a CLIA-certified lab (Laguna Hills, CA). HER2(+) DCIS was defined as patients with a HER2(3+) immunohistochemistry &gt;10% per ASCO/CAP guidelines. The IBR rate was calculated for the overall group of HER2(+) patients and those in the Residual Risk group. Individual patient outcome and biosignature results were analyzed using Kaplan Meier and Cox Proportional Hazard analyses.

Results: The biosignature classified 113 of the 178 (63%) HER2(+) women into the Residual Risk group (DS&gt;2.8 with RRt). Patients in the Residual Risk group had a significantly greater IBR (HR=8.3; 95%CI: 1.1,50, p=.012) over 10-years, with a corresponding 10-year total IBR rate of 16.2% (95%CI: 9.7%, 26.5%) versus 1.6% (95%CI: 0.2%, 10.9%) for all other HER2(+) patients. In univariate analysis, younger patients tended to have higher IBR rate after BCS plus RT, but only Residual Risk was significantly associated with IBR rate after BCS plus RT. Moreover, multivariable analysis demonstrated that the Residual Risk group was eight times more likely to recur after BCS and RT, while clinicopathologic factors (age, grade, tumor size) were not associated with higher IBR rates.

Conclusion: The DCISionRT Residual Risk group was predictive for 10-year IBR risk after BCS plus RT in women with HER2(+) DCIS. Approximately 40% of patients with HER2(+) DCIS would be expected to achieve low rates of recurrence with BCS and RT, while about 60% of these women (classified in the Residual Risk group) would have higher recurrence rates and may benefit from further therapy, such as HER2-directed therapies. These findings suggest that if the results of the B43 trial were re-analyzed using the predictive 7-gene biosignature (DCISionRT with Residual Risk Subtype), better clarity could be gained on the true impact of trastuzumab on IBR rates in patients with HER2(+) DCIS and the patients most likely to benefit from this additional therapy.

Table 1. Univariate and Multivariable Cox Proportional Hazards Analyses.

Citation Format: Frank Vicini, Chirag Shah, Rachel Rabinovitch, Pat Whitworth, Julie A. Margenthaler, Brian J. Czerniecki, DAVID J. DABBS, Sheila Weinmann, Michael Leo, G Bruce Mann, Fredrik Wärnberg, jess Savala, Steven C. Shivers, Karuna Mittal, Troy Bremer. Characterization of recurrence risk after lumpectomy and radiotherapy in HER2-positive ductal carcinoma in situ of the breast, using 7-gene predictive biosignature: Implications for the NSABP-B43 trial results [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-04-06.

Abstract P4-02-02: Changes in treatment recommendation for patients with Ductal Carcinoma In Situ using a 7-gene predictive biosignature: Analysis of the PREDICT Study

Background: The role of adjuvant radiotherapy (RT) following breast conserving surgery (BCS) for women with ductal carcinoma in situ (DCIS) remains controversial. Although there is Level 1 evidence supporting the use of RT in reducing the risk of local recurrence, prognostic and predictive tools are needed to better stratify individual risks and benefits of RT. The DCISionRT® Test (PreludeDx, Laguna Hills, CA) is a 7-gene predictive biosignature that uses tumor biology in conjunction with clinicopathologic factors. The test provides a validated score (DS) for women receiving BCS that assesses 10-year risk of DCIS recurrence and development of invasive breast cancer with and without adjuvant RT. We established a registry to evaluate the decision impact of the 7-gene predictive biosignature on DCIS treatment recommendations.

Methods: The PREDICT study is a prospective, multi-institutional registry for patients who received DCISionRT testing as part of their routine care. The registry includes females 26 and older who are diagnosed with DCIS and are candidates for BCS and eligible for RT or systemic therapy. Treating physicians completed treatment recommendation forms before and after receiving test reports to capture surgical, radiation and hormonal treatment (HT) recommendations and patient preferences. The primary endpoint is to identify the proportion of patients where testing led to a change in RT recommendation. Additional analyses include changes in recommendations in patient subgroups based on clinicopathologic factors or clinician specialty.

Results: Analysis was performed in 2,308 patients treated at 63 clinical sites. The median age of patients was 62 years, 18% were 50 or younger, nuclear grade was high in 33%, and tumor size was 2.5 cm or greater in 11%. Test results were DS Low Risk (DS ≤ 3) for 63% of women and 37% were DS Elevated Risk (DS &gt; 3). Overall, RT recommendation (yes/no) was changed for 38% of women after the 7-gene biosignature testing and HT recommendation was changed for 11%. There was a net decrease in RT recommendation from 71% pre-assay to 53% post-assay (p&lt; 0.001), where RT recommendations decreased 53% in DS Low Risk patients but increased 25% in DS Elevated Risk patients. Surgeons were more likely to change their RT recommendation (47%) than radiation oncologists (35%). When test results indicated DS Elevated Risk, both surgeons (79%) and radiation oncologists (88%) were likely to recommended RT, but when the results were DS Low risk, surgeons were more likely than radiation oncologists to recommend omitting RT (82% vs. 60%, respectively). Compared to traditional clinicopathologic features, the factor most strongly associated with RT recommendation was the biosignature result with other factors of importance being patient preference, tumor size and grade.

Conclusions: This analysis demonstrates significant changes in recommendations to add or omit RT based on the 7-gene predictive biosignature in 2,308 patients. The integration of DCISionRT into clinical decision processes has substantial impact on recommendations aimed at optimal management to prevent over- or under-treatment.

Table 1. Impact of the 7-gene predictive biosignature on adjuvant radiation recommended by clinicopathologic features.

Citation Format: Pat Whitworth, Steven C. Shivers, Chirag Shah, Rakesh Patel, Karuna Mittal, Troy Bremer, Charles Cox. Changes in treatment recommendation for patients with Ductal Carcinoma In Situ using a 7-gene predictive biosignature: Analysis of the PREDICT Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-02-02.

Multi-fidelity modelling of shark skin denticle flows: insights into drag generation mechanisms

We investigate the flow over smooth (non-ribletted) shark skin denticles in an open-channel flow using direct numerical simulation (DNS) and two Reynolds averaged Navier-Stokes (RANS) closures. Large peaks in pressure and viscous drag are observed at the denticle crown edges, where they are exposed to high-speed fluid which penetrates between individual denticles, increasing shear and turbulence. Strong lift forces lead to a positive spanwise torque acting on individual denticles, potentially encouraging bristling if the denticles were not fixed. However, DNS predicts that denticles ultimately increase drag by 58% compared to a flat plate. Good predictions of drag distributions are obtained by RANS models, although an underestimation of turbulent kinetic energy production leads to an underprediction of drag. Nevertheless, RANS methods correctly predict trends in the drag data and the regions contributing most to viscous and pressure drag. Subsequently, RANS models are used to investigate the dependence of drag on the flow blockage ratio (boundary layer to roughness height ratio), finding that the drag increase due to denticles is halved when the blockage ratio δ/h is increased from 14 to 45. Our results provide an integrated understanding of the drag over non-ribletted denticles, enabling existing diverse drag data to be explained.

A Novel Biosignature Identifies Patients With DCIS With High Risk of Local Recurrence After Breast Conserving Surgery and Radiation Therapy

PURPOSE

There is an unmet need to identify women diagnosed with ductal carcinoma in situ (DCIS) with a low risk of in-breast recurrence (IBR) after breast conserving surgery (BCS), which could omit radiation therapy (RT), and also to identify those with elevated IBR risk remaining after BCS plus RT. We evaluated a novel biosignature for a residual risk subtype (RRt) to help identify patients with elevated IBR risk after BCS plus RT.

METHODS AND MATERIALS

Women with DCIS treated with BCS with or without RT at centers in the US, Australia, and Sweden (n = 926) were evaluated. Patients were classified into 3 biosignature risk groups using the decision score (DS) and the RRt category: (1) Low Risk (DS ≤2.8 without RRt), (2) Elevated Risk (DS >2.8 without RRt), and (3) Residual Risk (DS >2.8 with RRt). Total and invasive IBR rates were assessed by risk group and treatment.

RESULTS

In patients at low risk, there was no significant difference in IBR rates with or without RT (total, P = .8; invasive IBR, P = .7), and there were low overall 10-year rates (total, 5.1%; invasive, 2.7%). In patients with elevated risk, IBR rates were decreased with RT (total: hazard ratio [HR], 0.25; P < .001; invasive: HR, 0.28; P = .005); 10-year rates were 20.6% versus 4.9% (total) and 10.9% versus 3.1% (invasive). In patients with residual risk, although IBR rates decreased with RT after BCS (total: HR, 0.21; P < .001; invasive: HR, 0.29; P = .028), IBR rates remained significantly higher after RT compared with patients with elevated risk (HR, 2.5; 95% CI, 1.2-5.4; P = .018), with 10-year rates of 42.1% versus 14.7% (total) and 18.3% versus 6.5% (invasive).

CONCLUSIONS

The novel biosignature identified patients with 3 distinct risk profiles: Low Risk patients with a low recurrence risk with or without adjuvant RT, Elevated Risk patients with excellent outcomes after BCS plus RT, and Residual Risk patients with an elevated recurrence risk remaining after BCS plus RT, warranting potential intensified or alternative treatment approaches.

Abstract B016: Guiding de-escalation of treatment for patients with DCIS using a predictive 7-gene biosignature: Identification of a clinically low-risk patient group

Background: NCCN treatment guidelines support de-escalation of radiotherapy (RT) for “low risk” patients with ductal carcinoma in situ (DCIS) treated with breast conserving surgery (BCS) for which improved specificity in identifying patients with low in-breast recurrence (IBR) rates who are unlikely to benefit from RT is needed. “low risk” has been defined as the absence of “high risk” clinicopathological (CP) factors, which include younger age (&lt;50 yrs) or tumors that are 2 cm or larger, palpable, or high nuclear grade. However, these CP factors have failed to identify a patient group with lower recurrence risk that do not clinically benefit from RT after BCS. Thus, the clinical utility of a Low Risk group identified by the predictive 7-gene biosignature was characterized overall and for patient subsets meeting “low risk” or “high risk” CP criteria. Methods: DCIS patients (n=926) from four international cohorts treated with BCS (negative margins) with (n=641) and without RT (n=335) were evaluated for CP criteria (age&lt;50 or grade 3, and RTOG 9804 like) and clinical outcomes. Formalin-fixed paraffin-embedded tissue samples for each patient were analyzed at a CLIA lab (PreludeDx, Laguna Hills, CA) for the predictive 7-gene biosignature with a Residual Risk subtype (RRt). The biosignature reported a decision score (DS) of 0-10 and presence/absence of the RRt subtype. A Low Risk group (DS≤2.8 without RRt) was compared with the combined Elevated Risk (DS&gt;2.8 without RRt) and Residual Risk groups (DS&gt;2.8 with RRt), where 10-yr total IBR rates were evaluated using Cox Proportional Hazards and Kaplan Meier analysis by treatment, biosignature Risk group, and CP criteria. Results: The biosignature classified 37% of women treated with BCS as Low Risk (n=338) and 63% (n=588) were classified into the combined Elevated/Residual Risk group. Among patients who did not receive RT, those in the Elevated/Residual Risk group had higher IBR rates (p&lt;.001) than those in the Low Risk group, with corresponding 10-yr IBR rates of 25.7% (95% CI: 18.8%, 34.4%) vs 5.6% (95% CI: 2.5%, 12.1%), respectively. RT did not reduce the IBR rate in the Low Risk group (p=0.71), where the 10-yr IBR rate was 4.8% (95% CI: 2.5%, 9.1%) after RT, corresponding to a number needed to treat (NNT) of ~100. However, the Elevated/Residual Risk group benefited from RT (p&lt;0.001), with a 17.7% (95% CI: 9.4%, 26%) absolute 10-year IBR rate reduction, corresponding to a NNT of 6. The biosignature reclassified 35-40% of patients with “high risk” CP criteria into the Low Risk group. IBR rates in the Low Risk group for patients with “high risk” CP were not significantly different than those with “low risk” CP criteria. Conclusion: The 7-gene biosignature was a better predictor of prognosis and RT benefit than standard CP risk stratification, identifying a low risk group with no significant benefit from RT. The 10-yr IBR rate with or without RT remained consistent in the biosignature Low Risk group independent of CP criteria, further supporting identification of a true low risk group who may forgo RT.

Citation Format: Rachel Rabinovitch, Frank A. Vicini, Chirag Shah, Julie Margenthaler, Brian Czerniecki, Pat Whitworth, Sheila Weinmann, Michael C. Leo, Fredrik Wärnberg, G. Bruce Mann, Steven C. Shivers, David Dabbs, Karuna Mittal, Troy Bremer. Guiding de-escalation of treatment for patients with DCIS using a predictive 7-gene biosignature: Identification of a clinically low-risk patient group [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr B016.

A Case Series Exploration of Multi-Regional Expression Heterogeneity in Triple-Negative Breast Cancer Patients

Extensive intratumoral heterogeneity (ITH) is believed to contribute to therapeutic failure and tumor recurrence, as treatment-resistant cell clones can survive and expand. However, little is known about ITH in triple-negative breast cancer (TNBC) because of the limited number of single-cell sequencing studies on TNBC. In this study, we explored ITH in TNBC by evaluating gene expression-derived and imaging-derived multi-region differences within the same tumor. We obtained tissue specimens from 10 TNBC patients and conducted RNA sequencing analysis of 2-4 regions per tumor. We developed a novel analysis framework to dissect and characterize different types of variability: between-patients (inter-tumoral heterogeneity), between-patients across regions (inter-tumoral and region heterogeneity), and within-patient, between-regions (regional intratumoral heterogeneity). We performed a Bayesian changepoint analysis to assess and classify regional variability as low (convergent) versus high (divergent) within each patient feature (TNBC and PAM50 subtypes, immune, stroma, tumor counts and tumor infiltrating lymphocytes). Gene expression signatures were categorized into three types of variability: between-patients (108 genes), between-patients across regions (183 genes), and within-patients, between-regions (778 genes). Based on the between-patient gene signature, we identified two distinct patient clusters that differed in menopausal status. Significant intratumoral divergence was observed for PAM50 classification, tumor cell counts, and tumor-infiltrating T cell abundance. Other features examined showed a representation of both divergent and convergent results. Lymph node stage was significantly associated with divergent tumors. Our results show extensive intertumoral heterogeneity and regional ITH in gene expression and image-derived features in TNBC. Our findings also raise concerns regarding gene expression based TNBC subtyping. Future studies are warranted to elucidate the role of regional heterogeneity in TNBC as a driver of treatment resistance.

Abstract 1674: FGF8 as a modulator of Wilms' tumor in vitro growth and longevity

Wilms’ tumor is the most common pediatric renal tumor accounting for 6-7% of all childhood cancers. Development of faithful Wilms’ tumor cell lines is needed to identify novel therapeutics. Currently, established Wilms’ tumor cell lines that are suitable for high throughput studies only represent anaplastic Wilms, a rare subtype. In contrast, cell lines representing the more common favorable histology Wilms’ tumor (FHWT) often have poor proliferative capacity and are unable to passage long-term (e.g. &gt;20 passages). For this reason, there is a need to establish robust cell lines representing FHWT. We hypothesize that there are core factors missing from the cell culture medium which prevent proper growth signaling and proliferation. We first performed bulk RNA-sequencing from patients and associated cell lines at Aflac Cancer and Blood Disorders Center with an underlying diagnosis of FHWT. Transcriptomic analyses showed that the reduced growth and proliferation in these FHWT cell lines may be due to reduced presence of the mitogenic fibroblast growth factor 8 (FGF8) in the cell culture environment as compared to the tumor environment. Wilms’ tumor has notably high FGF8 expression levels compared to all other pediatric tumors, implicating FGF8 as a potential driving factor in tumor maintenance. To characterize the phenotypic effects of FGF8 reintroduction in short term FHWT cell lines, we both endogenously overexpressed FGF8 via a lentiviral vector and ectopically added recombinant FGF8 to the cell culture medium. Qualitatively, endogenous overexpression of FGF8 induced distinct morphological changes in cells, converting the enlarged and flattened cells into more focal cells resembling proliferative early passage cells. Quantitatively, overexpression of FGF8 in one favorable histology cell line led to an increased rate of cellular proliferation and extended the cellular longevity by seven passages (47% above baseline). RNA-sequencing analysis of these FGF8 overexpressing cells implicated the anti-apoptotic gene, NTSR1, and an extracellular matrix protein, SNED1, as potential downstream targets of FGF8 overexpression. However, ectopic addition of recombinant FGF8 protein to the cellular medium had less pronounced effects, with seemingly cell-line specific effects. These data demonstrate FGF8 as possibly being required for survival in certain Wilms’ tumor cell lines that can be modulated to influence in vitro proliferation and longevity.

Citation Format: Garrett Cooper, Benjamin Lee, Nate Smyth, Karuna Mittal, Taylor Lawrence, Hunter Jonus, Jenny Shim, Kelly Goldsmith, Andrew Hong. FGF8 as a modulator of Wilms' tumor in vitro growth and longevity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1674.

Assessing the benefit of adjuvant endocrine therapy in patients following breast-conserving surgery with or without radiation stratified by a 7-gene predictive DCIS biosignature

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Background: Breast conserving surgery (BCS) followed by radiotherapy (RT) has been the mainstay for DCIS treatment. Adjuvant endocrine therapy (ET) has often been recommended based on multiple randomized clinical trials (RCT). However, these studies have failed to identify subsets of patients who did or did not benefit from adjuvant RT/ET therapy after BCS. We evaluated the association of a 7-gene predictive DCIS biosignature (PreludeDx, Laguna Hills, CA) to assess the impact of ET on 10-yr ipsilateral breast recurrence (IBR) risk after BCS alone or with RT. Methods: DCISionRT with integrated Residual Risk subtype (RRt) reported a decision score (DS) and three risk groups, a) Low Risk (DS≤2.8), b) Elevated Risk (DS > 2.8 without RRt) and c) Residual Risk (DS > 2.8 with RRt). DCISionRT/RRt was evaluated in 926 patients from 4 cohorts who were treated with BCS alone or with RT/ET. The three risk groups were assessed for 10-yr total (invasive and in situ) IBR risk by Kaplan Meier and Cox proportional hazards survival analysis. Results: DCISionRT/RRt classified 338 (37%) women as Low Risk, 399 (43%) as Elevated Risk, and 189 (20%) as Residual Risk. Overall, patients treated with ET had a significantly lower 10-yr IBR risk in multivariable analysis independent of RT (HR = 0.55, p = 0.033). In the Low Risk group treated with BCS without RT, the average 10-yr IBR risk was 5.6% (95% CI 2.5-12.1%, n = 124) and was not significantly different with vs without ET (p = 0.33). The 10-yr IBR risk after BCS alone was 22.6% in the Elevated Risk group and 50.3% in the Residual Risk group. Compared to BCS alone, the 10-year IBR risk tended to be lower in patients prescribed ET without RT in the Elevated (11.6%, 95% CI 3.9-32%) and Residual (15.4%, 95% CI 4.1-49%) Risk groups. 10-yr IBR risk was not significantly reduced by RT within the Low Risk group (p = 0.7) but was significantly reduced to 6.3% (95% CI 3.4-12%) by RT within the Elevated Risk (HR = 0.2, p < 0.001) and to 12.5% (95% CI 6.4-23%) within the Residual Risk (HR = 0.2, p < 0.001) groups. 10-yr IBR risk was significantly higher after RT in the Residual (HR = 2.5, p = 0.013) vs. Elevated Risk groups. After BCS and RT, there was no significant reduction in 10-yr IBR risk for those treated with vs without ET in the Elevated (p = 0.22) and Residual (p = 0.87) risk groups. Conclusions: The DCISionRT/RRt biosignature demonstrated prognostic and predictive RT response in Elevated and Residual Risk patients. Consistent with prior RCT data, ET was associated with lower 10-yr IBR risk overall, and within the DCISionRT Elevated and Residual Risk groups without RT. However, neither ET nor RT were asssociated with significant risk reduction in the Low Risk group. There was no added benefit of ET in the Elevated and Residual Risk groups after BCS+RT; the Residual Risk group patients still had a high IBR risk after RT.

Hypoxia Drives Centrosome Amplification in Cancer Cells via HIF1α-dependent Induction of Polo-Like Kinase 4

Centrosome amplification (CA) has been implicated in the progression of various cancer types. Although studies have shown that overexpression of PLK4 promotes CA, the effect of tumor microenvironment on polo-like kinase 4 (PLK4) regulation is understudied. The aim of this study was to examine the role of hypoxia in promoting CA via PLK4. We found that hypoxia induced CA via hypoxia-inducible factor-1α (HIF1α). We quantified the prevalence of CA in tumor cell lines and tissue sections from breast cancer, pancreatic ductal adenocarcinoma (PDAC), colorectal cancer, and prostate cancer and found that CA was prevalent in cells with increased HIF1α levels under normoxic conditions. HIF1α levels were correlated with the extent of CA and PLK4 expression in clinical samples. We analyzed the correlation between PLK4 and HIF1A mRNA levels in The Cancer Genome Atlas (TCGA) datasets to evaluate the role of PLK4 and HIF1α in breast cancer and PDAC prognosis. High HIF1A and PLK4 levels in patients with breast cancer and PDAC were associated with poor overall survival. We confirmed PLK4 as a transcriptional target of HIF1α and demonstrated that in PLK4 knockdown cells, hypoxia-mimicking agents did not affect CA and expression of CA-associated proteins, underscoring the necessity of PLK4 in HIF1α-related CA. To further dissect the HIF1α-PLK4 interplay, we used HIF1α-deficient cells overexpressing PLK4 and showed a significant increase in CA compared with HIF1α-deficient cells harboring wild-type PLK4. These findings suggest that HIF1α induces CA by directly upregulating PLK4 and could help us risk-stratify patients and design new therapies for CA-rich cancers.

IMPLICATIONS

Hypoxia drives CA in cancer cells by regulating expression of PLK4, uncovering a novel HIF1α/PLK4 axis.

Abstract P3-09-14: Whole exome sequencing of matched primary and metastatic triple-negative breast cancer samples

Background: Triple-negative breast cancer (TNBC) is a heterogeneous breast cancer subtype with distinct biological features and clinical behavior. TNBC is associated with an increased risk of metastasis and recurrence. In this whole exome study, we investigated the genetic profiles of primary TNBC tumors and paired metastases using next-generation sequencing (NGS). Methods: Genomic DNA extracted from 35 paraffin-embedded formalin-fixed (FFPE) tissues (15 primary tumors that did not metastasize, 11 primary tumors that metastasized, and nine paired metastatic tumors to the lymph nodes) was analyzed by whole exome sequencing (WES). Reads were trimmed using Trim-Galore and were aligned to the reference genome GRCh38 using Burrows-Wheeler Aligner (BWA). BAM files were preprocessed to optimize variant calling, and variant calling was carried out using the GATK pipeline. Variants were annotated using SnpEff. Tumors were analyzed for single nucleotide variants (SNV), point mutations, and insertions/deletions (indels). Results: Primary tumors that did not metastasize had a higher number of variants (~13,500) than primary tumors that metastasized (~12,900). However, the number of variants was similar between the primary tumors (~12,900 variants) and their matched metastases (~12,500 variants). MUC3A was the top mutated gene both in primary tumors that did not metastasize and in those that metastasized. MUC3A was also the top mutated gene in matched metastatic lesions. Moreover, we compared the mutational status of the most frequently mutated genes in TNBC samples from the TCGA and METABRIC datasets. We found that in our dataset, TP53, MAP3K1, and PTEN were mutated in 60%, 93%, and 7% of primary TNBC tumors without metastases and in 36%, 0%, and 36% of primary TNBC tumors that metastasized. Mutations in TP53 and PTEN were found in 2/9 and 1/9 of primary and metastases pairs, respectively. No mutations in PI3KCA were observed in any of the primary or matched metastatic tumors. Conclusions: We used WES to compare the genomic landscapes of primary TNBC tumors and matched metastatic tumors, as well as of primary TNBC tumors that metastasized and those that did not metastasize. We found very similar genomic alterations between the primary and paired metastatic tumors, indicating that genomic features may be retained during metastasis. Primary tumors that did not metastasize showed a greater extent of genomic alterations than primary tumors that metastasized.

Citation Format: Jaspreet Kaur, Darshan S. Chandrashekar, Zsuzsanna Varga, Emiel Janssen, Khanjan Gandhi, Karuna Mittal, Umay Kiraz, Sooryanarayana Varambally, Ritu Aneja. Whole exome sequencing of matched primary and metastatic triple-negative breast cancer samples [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-09-14.

Centrosome amplification: a quantifiable cancer cell trait with prognostic value in solid malignancies

Numerical and/or structural centrosome amplification (CA) is a hallmark of cancers that is often associated with the aberrant tumor karyotypes and poor clinical outcomes. Mechanistically, CA compromises mitotic fidelity and leads to chromosome instability (CIN), which underlies tumor initiation and progression. Recent technological advances in microscopy and image analysis platforms have enabled better-than-ever detection and quantification of centrosomal aberrancies in cancer. Numerous studies have thenceforth correlated the presence and the degree of CA with indicators of poor prognosis such as higher tumor grade and ability to recur and metastasize. We have pioneered a novel semi-automated pipeline that integrates immunofluorescence confocal microscopy with digital image analysis to yield a quantitative centrosome amplification score (CAS), which is a summation of the severity and frequency of structural and numerical centrosome aberrations in tumor samples. Recent studies in breast cancer show that CA increases across the disease progression continuum, while normal breast tissue exhibited the lowest CA, followed by cancer-adjacent apparently normal, ductal carcinoma in situ and invasive tumors, which showed the highest CA. This finding strengthens the notion that CA could be evolutionarily favored and can promote tumor progression and metastasis. In this review, we discuss the prevalence, extent, and severity of CA in various solid cancer types, the utility of quantifying amplified centrosomes as an independent prognostic marker. We also highlight the clinical feasibility of a CA-based risk score for predicting recurrence, metastasis, and overall prognosis in patients with solid cancers.

Abstract 3560: PLK4 is a HIF-1α target gene: A novel mechanism inducing centrosome amplification in tumor cells

Background: The presence of supernumerary or abnormally large centrosomes, also known as centrosome amplification (CA), drives tumor progression by enhancing chromosomal instability, and altering cellular microtubule cytoskeletons and tissue cytoarchitectures to promote the migration and invasion capabilities of cancer cells. Although the prevalence of CA is documented in a variety of cancer types, it remains unclear how CA is induced in tumor cells.This study aims to examine the role of intratumoral hypoxia in inducing CA via HIF-1α.

Methods: We (a) exposed cultured breast, pancreatic, colorectal and prostate cancer cells to hypoxia, and (b) genetically manipulated hypoxia [via overexpression (OE) or knock-out (KO) of HIF-1α], and quantitated CA employing immunocytofluorescence methods. We also quantitated the levels of CA-associated genes and proteins by qRT-PCR and western blot, respectively. Next, to discern the biological pathway through which HIF-1α induces CA, we performed ChIP and Luciferase reporter assays. We immunohistochemically labeled breast (n=24), colon (38), prostate (n=52), and pancreatic (n=34) cancer tissue samples for HIF-1α and PLK4. Serial sections from the same tumors were also immunofluorescently labeled for γ-tubulin and CA was quantitated. Using public microarray datasets (TCGA), we investigated whether centrosomal gene expression is enriched in tumors characterized by a high expression of a hypoxia gene expression signature.

Results: Cells cultured in hypoxic conditions exhibited higher CA (p&lt;0.05) than the cells cultured in normoxic conditions. CA levels increased when cells with HIF-1α OE were cultured in normoxic conditions and no significant induction of CA was observed when the HIF-1α KO cells were cultured under hypoxic conditions. ChIP and Luciferase assay confirmed that HIF-1α induced CA by directly upregulating the expression of PLK4. Moreover, when tumor cells were exposed to hypoxia after knock-down of PLK4, no significant changes in CA and CA-associated proteins were observed. In clinical patient samples (breast, colon, pancreatic and prostate cancer), we observed that HIF-1α expression was significantly (p&lt;0.05) correlated with PLK4 expression at the protein level (breast ρ=0.81, colon ρ=0.76, prostate ρ=0.68, and pancreatic ρ=0.67). Findings from our in silico analyses further validated these observations by showing a strong correlation between the expressions of HIF-1α and PLK4 at the transcriptional level. We also found that centrosomal gene expression is enriched in tumors with high hypoxia score (TCGA dataset of breast, colon, pancreatic and prostate cancer).

Conclusion: Collectively, our findings suggest that hypoxia drives CA in tumor cells through HIF-1α-mediated transcriptional upregulation of PLK4. Given the development of several promising HIF-1α inhibitors, this research could potentially aid in patient risk stratification for clinical decision-making, and enable design of new therapies.

Citation Format: Karuna Mittal, Jaspreet Kaur, Shaligram Sharma, Ishita Choudhary, Guanhao Wei, Precious Imhansi Jacob, Da Hoon Choi, Nagini Maganti, Shrikant Pawar, Michael S. Toss, Emiel A. Janssen, Meenakshi V. Gupta, Michelle D. Reid, Emad A. Rakha, Padmashree Rida, Ritu Aneja. PLK4 is a HIF-1α target gene: A novel mechanism inducing centrosome amplification in tumor cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3560.

A Quantitative Centrosomal Amplification Score Predicts Local Recurrence of Ductal Carcinoma In Situ

PURPOSE

The purpose of this study is to predict risk of local recurrence (LR) in ductal carcinoma in situ (DCIS) with a new visualization and quantification approach using centrosome amplification (CA), a cancer cell-specific trait widely associated with aggressiveness.

EXPERIMENTAL DESIGN

This first-of-its-kind methodology evaluates the severity and frequency of numerical and structural CA present within DCIS and assigns a quantitative centrosomal amplification score (CAS) to each sample. Analyses were performed in a discovery cohort (DC, n = 133) and a validation cohort (VC, n = 119).

RESULTS

DCIS cases with LR exhibited significantly higher CAS than recurrence-free cases. Higher CAS was associated with a greater risk of developing LR (HR, 6.3 and 4.8 for DC and VC, respectively; P < 0.001). CAS remained an independent predictor of relapse-free survival (HR, 7.4 and 4.5 for DC and VC, respectively; P < 0.001) even after accounting for potentially confounding factors [grade, age, comedo necrosis, and radiotherapy (RT)]. Patient stratification using CAS (P < 0.0001) was superior to that by Van Nuys Prognostic Index (VNPI; HR for CAS = 6.2 vs. HR for VNPI = 1.1). Among patients treated with breast-conserving surgery alone, CAS identified patients likely to benefit from adjuvant RT.

CONCLUSIONS

CAS predicted 10-year LR risk for patients who underwent surgical management alone and identified patients who may be at low risk of recurrence, and for whom adjuvant RT may not be required. CAS demonstrated the highest concordance among the known prognostic models such as VNPI and clinicopathologic variables such as grade, age, and comedo necrosis.

Abstract A088: Centrosomes take center stage: Comparative analysis of centrosome amplification in African American and European American patients with prostate cancer

Background: Prostatic adenocarcinoma (PCA) in African Americans (AA) is characterized by earlier onset, higher aggressiveness, more frequent metastases, and increased mortality rates compared to those in European Americans (EA). Exome and genome sequencing have revealed that PCA in AAs also exhibits high intratumor heterogeneity (ITH) than their counterparts in EAs. ITH poses challenges to both clinicians and drug developers when identifying low-level clones, predicting tumor evolution, developing clone-specific targeted drugs and evaluating effective, yet non-toxic combinatorial regimens to combat ITH. Amplified centrosomes (an abnormal increase in the number and/or volume of centrosomes) underlie erroneous mitoses and fuel chromosomal instability (CIN), which is a well-recognized driver of ITH. In this study, we evaluated the extent of centrosome amplification in tissue sections from PCA in AA and EA men. Design: We have pioneered a semi-automated pipeline that integrates immunofluorescence confocal microscopy with digital image analysis and yields a quantitative Centrosomal Amplification Score (CAS) for each tumor sample by evaluating severity and frequency of centrosomal aberrations therein. To this end, 115 formalin fixed paraffin embedded PCA tissue sections were firstly immunofluorescently stained for centrosomes followed by imaging and image analysis. Finally, we generated a composite CAS score (CAStotal) for each patient sample by integrating the numerical (CASi) and structural (CASm) aberrations. Results: High BMI (&gt;25) AA PCAs (n=37) exhibited significantly (p=0.04) higher CAStotal than EA (n=41) regardless of Gleason grade. Moreover, on analysis of grade matched PCAs we observed that CASm and CAStotal were significantly higher (p=0.02) in high grade (Gleason score &gt;7) in AA PCAs (n=34) when compared to EA (n=38) PCAs. Regardless of race tumors from men &gt; 54 years exhibited higher CAStotal (p=0.03) (high age group n=86 and low age =29). Conclusion: Our results suggest that AAs exhibit higher degree and severity of CA compared to EAs, which may render PCAs in AAs more sensitive to centrosome targeting/declustering drugs. This study suggests the potential usefulness of CAS in enabling patient stratification into more optimal treatment regimens and provides a novel tool that might help in personalized prostate cancer treatment with an overall goal of eliminating ethnic disparities in prostate cancer outcomes.

Citation Format: Karuna Mittal, Guanhao Wei, Jaspreet Kaur, Michelle Dian Reid, Ritu Aneja. Centrosomes take center stage: Comparative analysis of centrosome amplification in African American and European American patients with prostate cancer [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A088.

Abstract PR18: Prognostic role of androgen receptor in triple-negative breast cancer: A global multi-institutional experience

Background: African American (AA) triple-negative breast cancer (TNBC) patients experience worse clinical outcomes and exhibit 40% higher mortality rate than their European Americans (EAs) counterparts. There are currently no distinctions in inherent tumor biology between the ethnically distinct TNBC patients that serve as risk-predictive markers allowing new tailored treatments. Recently, androgen receptor (AR) has emerged as a new target for treating TNBC. However, the prognostic value of AR in TNBC remains controversial. To reconcile conflicting reports about the impact of AR loss on prognosis of TNBC and uncover the molecular pathways that may underlie the racial disparity in outcomes among AR-negative TNBCs, we determined the prognostic value of AR in diverse TNBC cohorts. Since loss of AR is associated with worse clinical outcome and African and AA women are more prone to aggressive disease course, we hypothesized that AR loss may underlie the global disparate burden in TNBC.

Methods: We evaluated AR expression in well-annotated formalin-fixed, paraffin-embedded TNBC resection samples (n=1351) obtained from multiple hospitals from US, UK, Norway, Ireland, Nigeria and India. Samples with ≥1% nuclei staining positive for AR were deemed to be AR-positive. Associations between AR status, clinicopathologic variables and overall survival (OS) were evaluated. We performed gene set enrichment analysis for AR low and high group in AA and EA TNBCs. In vitro experiments were performed to examine whether AR loss increased the metastatic potential of TNBC cells.

Results: We observed a significant difference in AR expression among EA and AA TNBCs (p=0.02) with AR loss associated with women of African ancestry (&gt;90%, p&lt;0.05). AR loss was significantly associated with poor OS in TNBC patients from US cohort (p=0.0324; n=316 for AR-negative, n=104 for AR-positive) and Nigerian cohort (p=0.0251; AR-negative=164, AR-positive=16). AR-negative was associated with poor OS in adjuvant-treated high Ki67 (&gt;14%) (HR=1.72; p=0.095) AA TNBC (n=98) when compared to EA TNBCs (n=80). Furthermore, AR status retained its significant prognostic value (HR=1.549, p=0.036) after controlling for age, grade, Ki67, race and chemotherapy status. Gene set enrichment analysis revealed that Wnt/β-catenin signaling was the top-enriched gene ontology in the AR-low TNBC subgroup. Moreover, β-catenin protein levels are higher in AA AR-low TNBCs compared with AA AR-high TNBCs (p&lt;0.05), suggesting Wnt signaling upregulation in AA women with AR-negative TNBC. In TNBC cell lines, loss of AR was significantly associated with higher cell proliferation, migration and invasion (p&lt;0.05).

Conclusion: Our study suggests a striking association of AR loss in TNBC with women of African ancestry. Our data offer compelling evidence that oncogenic Wnt/β-catenin signaling may link AR loss to more aggressive disease course and represent actionable biology in AA AR-negative TNBCs for whom no targeted treatments are currently on the horizon.

This abstract is also being presented as Poster C102.

Citation Format: Shristi Bhattarai, Sergey Klimov, Karuna Mittal, Uma Krishnamurthi, Xiaoxian Bill Li, Deepika Wali, Ceyda Sonmez Wetherilt, Ansa Riaz, Mohammad A. Aleskandarany, Andrew R. Green, Ian O. Ellis, Meenakshi Gupta, Lauren E. McCullough, Upender Manne, Johnson Agboola, Brett Baskovich, Emiel A. Janssen, Grace Callagy, Anurag Mehta, Tanuja Shet, Rakha A. Emad, Padmashree C.G. Rida, Ritu Aneja. Prognostic role of androgen receptor in triple-negative breast cancer: A global multi-institutional experience [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr PR18.

Molecular profiling and quantitative image analysis reveal spatial intratumor heterogeneity in TNBC

e12536

Background: Triple negative breast cancer (TNBC) is a molecularly complex and heterogeneous subtype with distinct biological features and clinical behavior. Extensive intra-tumor heterogeneity is suspected to be a major cause of therapeutic failure. Spatially-distinct parts of the tumor harbor diverse and divergent clonal populations of cancer cells. Thus it is likely increasing the likelihood that some of those clones resist treatment, expand in numbers and eventually, repopulate the tumor leading to recurrence and spread. Therefore, a deeper understanding of this complexity is fundamental to gaining insights into this clinically important issue. In this study, we used RNA sequencing and machine learning approaches to examine the molecular and phenotypic/cellular profiles of various tumor samples from the same patient tumor to reveal spatial intra-tumor heterogeneity in TNBCs. Methods: We used 34 samples (2-4 samples from each patient tumor) from a total of 11 unique TNBC patients. RNA-sequencing was performed to quantify differential gene expression and machine learning (ML) approaches (deep learning regression modeling) were used to quantify the percentage of tumor and tumor-infiltrating lymphocytes (TILs) in the H&E stained tissue sections. The extent of concordance/discordance between the multiple tumor samples that originated from the same patient was analyzed by analyzing the intra- and inter-patient variance of normalized tumor cell, TIL % and gene expression. We also performed pathway analysis to identify signaling pathways dysregulated within (intra-tumoral heterogeneity) and between tumors (inter-tumoral heterogeneity) and performed molecular subtype analysis. Results: We observed that gene expression variance as higher within-patient (intra-tumor) compared to between-patient (inter-tumor). Tumor samples from 70% of patients showed different molecular subtypes representing extensive intra-tumor heterogeneity. Our ML-based image analysis showed that intra-patient tumor cell and TILs density/percentage variance was greater than inter-patient variance. In addition, patients with high within-patient gene expression variability had a high tumor and TIL variance. Among the within-patient expression variability, the genes associated with the PLK1 and Notch signaling were enriched. Conclusions: Our results suggest that TNBCs exhibit higher intra-tumor gene expression and cellular variance compared to inter-tumor gene expression and cellular variance suggesting higher intra-tumor heterogeneity in TNBCs.

Abstract P3-05-02: Upregulation of canonical Wnt signaling may underlie an aggressive disease course in androgen receptor-negative triple negative breast cancer

Background: Based on the expression of androgen receptor (AR), triple-negative breast cancer (TNBC) is subdivided into AR-positive and AR-negative subtypes. Although AR is a potential therapeutic target for AR-positive TNBC, its prognostic role in TNBC remains controversial. Lack of AR expression is associated with a more aggressive disease course. Whereas AR-positive TNBC responds well to AR antagonists, there are, beyond chemotherapy, no targeted drugs available for AR-negative patients. Thus, we aimed to examine the impact of AR loss on the prognosis for TNBC and to uncover molecular pathways/drivers that can be therapeutically targeted in AR-negative TNBC.

Methods: We evaluated AR expression immunohistochemically in annotated, formalin-fixed paraffin-embedded samples from 420 TNBC patients obtained from various institutions in the US. Samples with ≥1% of AR-positive nuclei were deemed AR-positive. We next performed genome-wide copy number profiling (array-CGH analysis) to determine whether losses and/or deletions of the AR gene contributed to tumor aggressiveness of AR-negative TNBC. Finally, using a combination of in silico analysis, in vitro assays, and RNA-sequencing, we found molecular drivers/pathways that were upregulated in AR-negative TNBC.

Results: AR was expressed in approximately 25% of the total cases, and loss of AR was associated with poor overall survival of TNBC patients (p=0.03; n=316 for AR-negative, n=104 for AR-positive) among all treated patients as well as among the subset of adjuvant chemotherapy-treated patients (p=0.06; n=230 for AR-negative, n=75 for AR-positive). Further, the array-CGH analysis showed that AR-negative TNBC presented higher levels of copy number alterations compared to AR-positive TNBC (28.5±4.40 and 13.79±3.48, P&lt;0.01, respectively). These alterations affected mainly the cytobands 1p36.33-p36.32, 1q21.1-q44, 9p24.3-p13.1, 10p15.3-p11.21, 11p15.5-p11.2, 12p13.33-p11.21, 19p13.2-p12, 20q11-q13.33, and 22q11.1-q12.3 cytobands, which were present in higher numbers of AR-negative TNBC.

Next-generation RNA-sequencing of TNBC cases and gene set enrichment analysis revealed upregulation of the Wnt/β-catenin axis in AR-negative cases. Proteomic data from TCGA showed upregulation of β-catenin and Dvl3 expression-evidence of overexpression of Wnt signaling in AR-negative TNBC. Furthermore, protein levels of β-catenin were higher in AR-negative TNBCs compared to AR-positives (p&lt;0.05), suggesting aberrant activation of Wnt/β-catenin signaling in AR-negative TNBC. Using reporter gene assays in cultured cells, we confirmed the activation of Wnt signaling and elevated levels of Wnt target genes (Axin2, CD44, and Cyclin D1) in AR-negative TNBC cells relative to AR-positives. Enhanced nuclear accumulation of β-catenin in AR-negative TNBC indicated reduced β-catenin phosphorylation. Knockdown of AR in AR-positive TNBC cells showed features of AR-negative phenotype in AR-positive cells, in that we observed reduced expression of E-cadherin (suggesting enhanced epithelial-mesenchymal transition) and higher β-catenin expression. Concomitantly, β-catenin target genes were also upregulated resulting in enhanced proliferation, migration and invasion capacities (p&lt;0.05).

Conclusion: Our results suggest an association of AR loss with poor clinical outcome in TNBC. The data support the dysregulation of the oncogenic Wnt/β-catenin pathway in AR-negative cancer cells. Finally, we elucidated a previously unknown link of AR loss to a more aggressive disease course and discovered actionable targets in AR-negative TNBCs.

Citation Format: Shristi Bhattarai, Chakravarthy Garlapati, Komal Arora, Karuna Mittal, Sergey Klimov, Uma Krishnamurti, Xiaoxian B Li, Deepika Wali, Meenakshi Gupta, Upender Manne, Shobhna Kapoor, Luicane Cavalli, Ritu Aneja. Upregulation of canonical Wnt signaling may underlie an aggressive disease course in androgen receptor-negative triple negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-05-02.

Spotlighting the hypoxia-centrosome amplification axis

The abysmal success rate of anticancer drugs in clinical trials, is in part, attributable to discordance between cultured cancer cells and patient tumors. While tumors in vivo, display a lower mitotic index, patient tumors portray much higher centrosomal aberrations, relative to in vitro cultured cells. The microenvironment too differs considerably between the in vitro and in vivo scenarios. Notably, another hallmark of cancer, hypoxia, is not recapitulated in cell lines cultured under normoxic conditions. These observations raise the possibility that hypoxia may be the missing link that explains the discordance between cell biological phenomena in vitro versus physiological conditions. Further, the interplay between hypoxia and centrosome amplification (CA) is relatively understudied. Recent research from our laboratory, geared toward examining the biological link between the two, has uncovered that hypoxia induces the expression of proteins (Plk4, Aurora A, Cyclin D) implicated in CA, in a hypoxia-inducible factor 1α (HIF-1α)-dependent context. Our studies evidence that hypoxia fuels CA that underlie intratumoral heterogeneity and metastatic potential of cancer cells. Given the advent of HIF-1α inhibitors, this research has ramifications in aiding patient risk stratification and designing new cancer drug therapies to facilitate clinical decision-making.

Collagen (XI) alpha-1 chain is an independent prognostic factor in breast ductal carcinoma in situ

Collagen11A1 (COL11A1) is a fibrillary type collagen constituting a minor component of the extracellular matrix and plays role in tissue tensile strength. Overexpression of COL11A1 expression is associated with aggressive behavior and poor outcome in several human malignancies. In this study, we evaluated the association between COL11A1 expression and clinicopathological parameters of the breast ductal carcinoma in situ (DCIS) and its prognostic value. COL11A1 protein expression was assessed immunohistochemically in a large well-characterized cohort of DCIS including pure (n = 776) and DCIS associated with invasive carcinoma (DCIS-mixed, n = 239). COL11A1 expression was assessed in tumor cells and surrounding stromal cells, and correlated with clinicopathological parameters, immunoprofile and disease outcome. In pure DCIS, high COL11A1 expression was observed in tumor cells and surrounding stromal cells in 25 and 13% of cases, respectively. Higher COL11A1 expression within the stromal cells was associated with hormone receptor negative, HER2 enriched and triple negative molecular subtypes and showed a positive linear correlation with proliferation index, dense tumor infiltrating lymphocytes and hypoxia-inducible factor 1 alpha. COL11A1 expression in tumor and stromal cells was significantly higher in DCIS associated with invasive carcinoma than in pure DCIS, and within the DCIS-mixed cohort, the invasive component showed higher COL11A1 expression than the DCIS component (all, p < 0.0001). Overexpression of stromal COL11A1 was an independent predictor of shorter local recurrence-free interval for all recurrences (HR = 13.2, 95% CI = 6.9-25.4, p < 0.0001) and for invasive recurrences (HR = 11.2, 95% CI = 4.9-25.8, p < 0.0001). When incorporated with other risk factors, stromal COL11A1 provided better patient risk stratification. DCIS with higher stromal COL11A1 expression showed poor outcome even with adjuvant radiotherapy management. In conclusion, overexpression of stromal COL11A1 is associated with invasive recurrence in DCIS and is a potential marker to predict the response to radiotherapy.

Geometric characteristics of collagen have independent prognostic significance in breast ductal carcinoma in situ: an image analysis study

Collagen plays a key role in normal and malignant tissue homeostasis. While the prognostic significance of collagen fiber remodeling in invasive breast cancer has been studied, its role in ductal carcinoma in situ (DCIS) remains poorly defined. Using image analysis, we aimed to evaluate the prognostic significance of the geometric characteristics of collagen surrounding DCIS. A large well-characterized cohort of DCIS comprising pure DCIS (n = 610) and DCIS coexisting with invasive carcinoma (n = 180) were histochemically stained for collagen using picrosirius red. ImageJ software was used to assess collagen density, degree of collagen fiber dispersion and directionality in relation to DCIS ducts' boundary. We developed a collagen prognostic index and evaluated its prognostic significance. A poor index was observed in 24% of the pure DCIS and was associated with determinants of high-risk DCIS including higher nuclear grade, comedo type necrosis, hormonal receptor negativity, HER2 positivity and high proliferation index. High collagen prognostic index was associated with the collagen remodeling protein prolyl-4-hydroxlase alpha subunit 2 and the hypoxia-related protein hypoxia inducible factor 1α. DCIS coexisting with invasive breast cancer had a higher collagen prognostic index than pure DCIS ( p < 0.0001). High index was an independent poor prognostic factor for DCIS recurrence for all recurrences (HR = 2.3, p = 0.005) and just invasive recurrences (HR = 3.4, p = 0.003). Interaction between collagen prognostic index and radiotherapy showed that the index was associated with poor outcome even with adjuvant radiotherapy ( p = 0.0001). Collagen reorganization around DCIS is associated with poor outcome and provides a potential predictor for disease progression and resistance to radiotherapy. Mechanistic studies are warranted to decipher the underlying mechanisms.

New sonographic marker of borderline ovarian tumor: microcystic pattern of papillae and solid components

OBJECTIVE

To describe and evaluate the utility of a new sonographic microcystic pattern, which is typical of borderline ovarian tumor (BOT) papillary projections, solid component(s) and/or septa, as a new ultrasound marker that is capable of distinguishing BOT from other adnexal masses, and to present/obtain histologic confirmation.

METHODS

In this retrospective study, we identified women with a histologic diagnosis of BOT following surgical resection who had undergone preoperative transvaginal ultrasound (TVS) examination. All images were reviewed for presence or absence of thin-walled, fluid-filled cluster(s) of 1-3-mm cystic formations, associated with solid component(s), papillary projections and/or septa. From the same cases, histopathologic slides of each BOT were examined for presence of any of these microcystic features which had been identified on TVS. To confirm that the microcystic TVS pattern is unique to BOTs, we also selected randomly from our ultrasound and surgical database 20 cases of epithelial ovarian cancer and 20 cases of benign cystadenoma, for review by the same pathologists. To confirm the novelty of our findings, we searched PubMed for literature published in the English language between 2010 and 2018 to determine whether the association between microcystic tissue pattern and BOT has been described previously.

RESULTS

Included in the final analysis were 62 patients (67 ovaries) with preoperative TVS and surgically confirmed BOT on pathologic examination. The mean patient age at surgery was 39.8 years. The mean BOT size at TVS was 60.7 mm. Of the 67 BOTs, 47 (70.1%) were serous, 15 (22.4%) were mucinous and five (7.5%) were seromucinous. We observed on TVS a microcystic pattern in the papillary projections, solid component(s) and/or septa in 60 (89.6%) of the 67 BOTs, including 46 (97.9%) of the 47 serous BOTs, 11 (73.3%) of the 15 mucinous BOTs and three (60.0%) of the five seromucinous BOTs. On microscopic evaluation, 60 (89.6%) of the 67 samples had characteristic 1-3-mm fluid-filled cysts similar to those seen on TVS. In seven cases there was a discrepancy between sonographic and histologic observation of a microcystic pattern. The 20 cystadenomas were mostly unilocular and/or multilocular and largely avascular. None of them or the 20 epithelial ovarian malignancies displayed microcystic characteristics, either on TVS or at histology. On review of 23 published articles in the English medical literature, containing 163 sonographic images of BOT, we found that, while all images contained it, there was no description of the microcystic tissue pattern.

CONCLUSION

We report herein a novel sonographic marker of BOT, a 'microcystic pattern' of BOT papillary projections, solid component(s) and/or septa. This was seen in the majority of both serous and mucinous BOT cases. Importantly, based on comparison of sonographic images and histopathology of benign entities and malignancies, the microcystic appearance seems to be unique to BOTs. No similar description has been published previously. Utilization of this new marker should help to identify BOT correctly, discriminating it from ovarian cancer and benign ovarian pathology, and should ensure appropriate clinical and surgical management. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Prognostic significance of cathepsin V (CTSV/CTSL2) in breast ductal carcinoma in situ

AIMS

Cathepsin V (CTSV/CTSL2) is a lysosomal cysteine proteinase and plays a role in extracellular matrix degradation. It is associated with poor prognosis in invasive breast cancer (IBC), but its role in breast ductal carcinoma in situ (DCIS) remains unclear. In this study, we aimed to evaluate the prognostic significance of CTSV in DCIS.

METHODS

CTSV protein expression was immunohistochemically assessed in a well-characterised and annotated cohort of DCIS comprising pure DCIS (n=776) and DCIS coexisting with IBC (n=239). CTSV expression was analysed in tumour cells and surrounding stroma, including its association with clinicopathological parameters and outcome.

RESULTS

In pure DCIS, high CTSV expression was observed in 29% of epithelial tumour cells and 20% of surrounding stroma. High expression in both components was associated with features of poor prognosis including higher nuclear grade, hormone receptor negativity and HER2 positivity. In addition, stromal CTSV expression was associated with larger DCIS size, comedo-type necrosis and high proliferation index. DCIS associated with IBC showed higher CTSV expression than pure DCIS either within the epithelial tumour cells or surrounding stroma (p<0.0001 and p=0.001, respectively). In DCIS/IBC, CTSV expression was higher in the invasive component than DCIS component either in tumour cells or surrounding stroma (both p<0.0001). CTSV stromal expression was associated with invasive recurrence independent of other prognostic factors in patients treated with breast conserving surgery (HR=3.0, p=0.005).

CONCLUSION

High expression of CTSV is associated with poor outcome in DCIS and is a potential marker to predict DCIS progression to invasive disease.

The prognostic significance of lysosomal protective protein (cathepsin A) in breast ductal carcinoma in situ

AIMS

Cathepsin A (CTSA) is a key regulatory enzyme for galactoside metabolism. Additionally, it has a distinct proteolytic activity and plays a role in tumour progression. CTSA is differentially expressed at the mRNA level between breast ductal carcinoma in situ (DCIS) and invasive breast carcinoma (IBC). In this study, we aimed to characterise CTSA protein expression in DCIS and evaluate its prognostic significance.

METHODS AND RESULTS

A large cohort of DCIS [n = 776 for pure DCIS and n = 239 for DCIS associated with IBC (DCIS/IBC)] prepared as a tissue microarray was immunohistochemically stained for CTSA. High CTSA expression was observed in 48% of pure DCIS. High expression was associated with features of poor DCIS prognosis, including younger age at diagnosis (<50 years), higher nuclear grade, hormone receptor negativity, HER2 positivity, high proliferative index and high hypoxia inducible factor 1 alpha expression. High CTSA expression was associated with shorter recurrence-free interval (RFI) (P = 0.0001). In multivariate survival analysis for patients treated with breast conserving surgery, CTSA was an independent predictor of shorter RFI (P = 0.015). DCIS associated with IBC showed higher CTSA expression than pure DCIS (P = 0.04). In the DCIS/IBC cohort, CTSA expression was higher in the invasive component than the DCIS component (P < 0.0001).

CONCLUSION

CTSA is not only associated with aggressive behaviour and poor outcome in DCIS but also a potential marker to predict co-existing invasion in DCIS.

Abstract P5-18-02: A quantitative centrosomal amplification score (CAS) predicts local recurrence in ductal carcinoma in situ

Background: About 60-80% of ductal carcinoma in situ (DCIS) cases are high-grade (HG) DCIS with an elevated risk of local recurrence (LR) even after a lumpectomy. Patients are often under or over treated due to the lack of accurate recurrence risk prediction models. Current prognostic models such as OncotypeDX and Van Nuys Prognostic Index (VNPI) lack consistency and are limited to a specific subset of patients. Here in this study, we show that the extent of centrosome amplification (CA) in a DCIS lesion can predict the risk of LR after lumpectomy. CA refers to presence of supernumerary or large centrosomes and is a characteristic of pre-invasive lesions, and breast tumors, and promotes erroneous mitoses and chromosomal instability.

Methods: We have pioneered a semi-automated pipeline that integrates immunofluorescence confocal microscopy with digital image analysis and yields a quantitative Centrosomal Amplification Score (CAS) for each patients' tumor sample by evaluating severity and frequency of centrosomal aberrations therein. To this end, we first immunofluorescently stained centrosomes in formalin fixed paraffin embedded resection samples from DCIS patients (discovery cohort n=133 and a validation cohort n=119) using an antibody against γ-tubulin, and co-stained nuclei with DAPI. Next, we imaged the slides and processed the raw 3D image data using IMARIS Biplane 8.2 3D volume rendering software. Finally, we calculated centrosome numbers and volume in ˜250 cells from each patient sample. Using a mathematical algorithm, we generated a composite CAS score for each patient sample by integrating the numerical (CASi) and structural (CASm) aberrations.

Results: We found that DCIS patients with recurrence exhibited higher CAS. Intriguingly, higher CAS was also associated with greater risk of developing ipsilateral breast events [Hazard ratio (HR) =7.58 for discovery cohort and HR=5.8 for validation cohort, p&lt;0.0001] which remained significant (HR=8.5 for discovery and HR=3.39, p&lt;0.0001) after accounting for the confounding factors like age, tumor size, comedo necrosis and radiotherapy. Kaplan Meir survival analysis indicated that high CAS was associated with poor recurrence-free survival (RFS) (p&lt;0.001). For the high and low CAS groups, the 5-year risk of recurrence was 87.5% and 12.5% respectively (p&lt;0.001). In our discovery cohort, a head-to-head comparison of the ability of VNPI and CAS to predict recurrence illuminated that CAS was able to stratify the DCIS group in recurrence and recurrence-free group with much higher significance (p&lt;0.0001) than the Van Nuys Prognostic Index (VNPI) (HRs for CAS- 8.8 vs. VNPI 0.959). Finally, the Harrell's concordance index using SAS PROC PHREG tests yielded that the probability of a patient with poorer/lower RFS to be in the high CAS group is 76.2%.

Conclusion: Our data compellingly show that CAS quantifies the risk of recurrence in DCIS patients with the highest concordance and provides a novel and innovative tool to tailor their treatment based on their risk profile.

Citation Format: Mittal K, Kaur J, Wei G, Toss MS, Osan RM, Janssen EA, Søiland H, Rakha EA, Rida PC, Aneja R. A quantitative centrosomal amplification score (CAS) predicts local recurrence in ductal carcinoma in situ [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-18-02.

Abstract PR02: β-Catenin overexpression underlies the aggressive disease course in African American triple-negative breast cancer patients who lack androgen receptor

Background: Androgen receptor (AR) has emerged as a new target for treating TNBC. AR is expressed in 10-43% of TNBCs. Although there are conflicting reports in the literature about the effect of AR status on TNBC prognosis, agents targeting AR signaling (enzalutamide) are already being evaluated in AR-positive TNBCs in early-stage clinical trials. However, no study so far has evaluated the association/correlation of AR status with ethnicity in TNBCs and downstream effects of AR loss in TNBCs. Given the association of AR loss with poor prognosis in breast cancer and that the African American (AA) with TNBC suffers aggressive disease course when compared to European American (EA) TNBCs, we hypothesized that AR loss might be an underlying cause of aggressive disease course in AR-negative TNBCs. Thus, in this project we aimed to study if loss or gain of AR in AA and EA TNBCs regulates the expression of β-catenin and leads to more aggressive disease course by activating downstream canonical Wnt-beta catenin signaling.

Methods: We evaluated AR expression immunohistochemically in 424 formalin-fixed, paraffin-embedded samples from TNBC patients for whom complete clinicopathologic and overall survival (OS) data were available. Samples with &lt;1% nuclear-stained cells were considered quadruple-negative. We also performed gene set enrichment analysis for the AR low and high group in AA and EA TNBCs using the publicly available TCGA gene dataset. Finally, we compared levels of 187 proteins with suspected involvement in breast tumorigenesis in AR-high vs AR-low TNBCs (using median AR expression as a cutpoint, as the IHC-derived AR status of these samples was unknown).

Results: IHC staining of AR indicated that 79.5% of AA TNBCs (n=214) and 70% of EA TNBCs (n=210) were AR negative. Loss of AR was associated with poor overall survival in adjuvant-treated high Ki67 (&gt;14%) (HR=1.72; p=0.095) AA TNBC (n=98) when compared to EA TNBCs (n=80). These data were validated by our in silico findings, which suggested that EA TNBCs (n=81) exhibited higher levels of AR mRNA compared to AA TNBCs (n=41) (p&lt;0.05). Similarly, AR protein expression was higher in EA TNBCs (n=75) than AA TNBCs (n=32) (p&lt;0.05). We further observed that β-catenin protein levels are higher in AA AR-low TNBCs compared with AA AR-high TNBCs (median AR expression used as cut point; p&lt;0.05). This was strengthened by our observation in a cohort of 142 TNBCs wherein AAs with AR-negative TNBC showed a preponderance of cells with nuclear β-catenin staining via IHC compared with EA TNBCs that lack AR. Our GSEA analysis results indicated that Wnt/β-catenin signaling was the top-enriched gene ontology in the AR-low subgroup compared to AR-high subgroup of TNBCs. Furthermore, proteomic data revealed that β-catenin and Dvl3 expression was significantly upregulated in the AR-low subgroup when compared with AR-high group, suggesting that Wnt signaling is in an overdrive in the AR-low subgroup, especially in AA TNBCs.

Conclusion: This study suggests that increased expression of β-catenin coupled with AR loss in AAs may underlie the ethnic disparity in outcomes among TNBC patients and strongly supports the prognostic role of AR and β-catenin in this breast cancer subtype.

Citation Format: Karuna Mittal, Shristi Bhattarai, Sergey Klimov, Uma Krishnamurthi, Xiaoxian Li, Ceyda Sonmez Wetherilt, Mohammad A. Aleskandaran, Andrew A. Green, Emad A. Rakha, Ian O. Ellis, Guilherme Cantuaria, Guanhao Wei, Remus Mihai Osan, Meenakshi V. Gupta, Upender Manne, Padmashree C.G Rida, Ritu Aneja. β-Catenin overexpression underlies the aggressive disease course in African American triple-negative breast cancer patients who lack androgen receptor [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr PR02.

Abstract P1-01-23: Hypoxia induced centrosome amplification via HIF-1α/Plk4 signaling axis associates with poorer overall survival in TNBC

Background: Centrosome amplification (CA) which refers to presence of supernumerary or abnormally large centrosomes drives tumor progression by promoting chromosomal instability and the generation of aggressive tumor clones. Although the role of CA in cancer progression is well-defined, no studies have yet discussed how CA is induced in tumor cells. We report here that intra-tumoral hypoxia, which is considered one of the major contributors to intratumor heterogeneity, induces CA via HIF-1α.

Methods: We first immunohistochemically labeled 24 breast carcinoma and uninvolved adjacent normal tissue samples for HIF-1α and calculated weighted indices (WIs) for nuclear HIF-1α. Adjacent serial sections from the same tumors were also immunofluorescently labeled for γ-tubulin and CA was calculated. Using public microarray datasets (Kao dataset, n=327), we investigated whether centrosomal gene expression is enriched in breast tumors characterized by a hypoxia gene expression signature. Finally, to determine the role of hypoxia in CA induction we exposed cultured TNBC cells (MDA-MB-231 and MDA-MB-468) to hypoxia and overexpressed (OE) and knocked out (KO) HIF-1α in TNBC cells and quantitated CA. Additionally, to discern the biological pathway through which HIF-1α induces CA we performed ChIP assay and in silico analyses to identify the possible targets of HIF-1α.

Results: A strong positive correlation between nuclear HIF-1α WI and CA was found in breast tumor samples (Spearman's rho p=0.722, p&lt;0.001). In addition, we found that higher nuclear HIF-1α was associated with worse overall survival (p=0.041; HR=1.03). Our in silico findings suggest that breast tumors with high expression of hypoxia-associated genes exhibited higher expression of centrosomal genes than breast tumors with low expression of hypoxia-associated genes. In addition, cells cultured in hypoxic conditions exhibited ˜1.5 fold higher (p&lt;0.05) CA when compared to the cells cultured in normoxic conditions. Interestingly level of CA decreased when HIF-1α KO TNBC cells were exposed to hypoxia and it increased when HIF-1α OE TNBC cells were culture in normoxic conditions. Furthermore, we discovered that HIF-1α induced CA by directly regulating the expression of Plk4 which was confirmed by performing ChIP assay. Our results indicated HIF-1α interaction with the motif in the PLK4 promoter from genomic DNA of MDA-MB 231 cells under hypoxic conditions, was significantly (p=0.04) higher when compared with the cells cultured under normoxic conditions. Plk4 mRNA expression was assessed using the online BC gene expression data sets (n=25). We found significantly higher expression of Plk4 in TNBC (n=374) when compared with non-TNBC (n=4098) and it was associated with poor overall survival (HR=1.76; p=0.054) in TNBC.

Conclusion: Collectively our findings suggest that hypoxia drives CA in TNBC via HIF-1α and contribute to poor outcomes. Thus, determination of CA and HIF-1α can help risk stratification in TNBC patients for more personalized treatments.

Citation Format: Mittal K, Choi DH, Maganti N, Ogden A, Melton BD, Kaur J, Gupta MV, Jonsdottir K, Janseen EAM, Aleskandarany MA, Rakha EA, Rida PCG, Aneja R. Hypoxia induced centrosome amplification via HIF-1α/Plk4 signaling axis associates with poorer overall survival in TNBC [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-01-23.

Association of hypoxia-induced centrosome amplification with clinical outcomes in triple-negative breast cancer

e23170

Background: Centrosome amplification (CA) which refers to presence of supernumerary or abnormally large centrosomes is believed to drive tumor progression by promoting chromosomal instability and the generation of aggressive tumor clones that are more capable of rapid metastasis. Not much is known about factors that drive CA within solid tumors. We have previously shown the existence of rampant CA in triple-negative breast cancers (TNBCs).We report here thatintratumoral hypoxia, which is one of the major contributors to tumor heterogeneity, induces CA in TNBCs via HIF-1α. Methods: We immunohistochemically labeled 24 TNBC and adjacent normal tissue samples for HIF-1α and derived weighted indices (WIs) for nuclear HIF-1α. Adjacent serial sections from the same tumors were immunofluorescently labeled for the centrosomal marker γ-tubulin and CA was determined. Using public microarray datasets (Kao dataset, n = 327), we investigated whether centrosomal gene expression is enriched in breast tumors characterized by a hypoxia gene expression signature. Finally, to test the role of hypoxia in CA induction we exposed cultured TNBC cells (MDA-MB-231 and MDA-MB-468) to hypoxia and overexpressed (OE) or knocked out (KO) HIF-1α and quantitated CA. Results: A strong positive correlation was found between nuclear HIF-1α WI and CA in TNBC samples (Spearman’s rho p = 0.722, p < 0.001), and higher nuclear HIF-1α was associated with worse overall survival (p = 0.041; HR = 1.03). Furthermore, breast tumors with high expression of hypoxia-associated genes exhibited higher expression of centrosomal genes than breast tumors with low expression of hypoxia-associated genes. TNBC cells cultured in hypoxic conditions exhibited ~1.5 fold higher (p < 0.05) CA compared to cells cultured in normoxic conditions. Interestingly, level of CA decreased when HIF-1α KO TNBC cells were exposed to hypoxia; conversely, CA increased when HIF-1α OE TNBC cells were cultured in normoxic conditions. Conclusions: Thus,intratumoral hypoxia drives CA in TNBC via HIF-1α and contributes to poor outcomes. Determination of CA may help identify TNBC patients who could benefit from centrosome declustering drugs and HIF-1α inhibitors.

Multinucleated polyploidy drives resistance to Docetaxel chemotherapy in prostate cancer

BACKGROUND

Docetaxel is the only FDA-approved first-line treatment for castration-resistant prostate cancer (CRPC) patients. Docetaxel treatment inevitably leads to tumour recurrence after an initial therapeutic response with generation of multinucleated polyploid (MP) cells. Here we investigated role of MP cells in clinical relapse of CRPC.

METHODS

Prostate cancer (PC-3) cells were treated with docetaxel (5 nM) for 3 days followed by a washout and samples were collected at close intervals over 35 days post drug washout. The tumorigenic potential of the giant MP cells was studied by implanting MP cells subcutaneously as tumour xenografts in nude mice.

RESULTS

Docetaxel-induced polyploid cells undergo mitotic slippage and eventually spawn mononucleated cells via asymmetric cell division or neosis. Both MP and cells derived from polyploid cells had increased survival signals, were positive for CD44 and were resistant to docetaxel chemotherapy. Although MP cells were tumorigenic in nude mice, these cells took a significantly longer time to form tumours compared with parent PC-3 cells.

CONCLUSIONS

Generation of MP cells upon docetaxel therapy is an adaptive response of apoptosis-reluctant cells. These giant cells ultimately contribute to the generation of mononucleated aneuploid cells via neosis and may have a fundamental role precipitating clinical relapse and chemoresistance in CRPC.

Multi-institutional study of nuclear KIFC1 as a biomarker of poor prognosis in African American women with triple-negative breast cancer

Nuclear KIFC1 (nKIFC1) predicts worse outcomes in breast cancer, but its prognostic value within racially distinct triple-negative breast cancer (TNBC) patients is unknown. Thus, nKIFC1 expression was assessed by immunohistochemistry in 163 African American (AA) and 144 White TNBC tissue microarrays (TMAs) pooled from four hospitals. nKIFC1 correlated significantly with Ki67 in White TNBCs but not in AA TNBCs, suggesting that nKIFC1 is not merely a surrogate for proliferation in AA TNBCs. High nKIFC1 weighted index (WI) was associated with significantly worse overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS) (Hazard Ratios [HRs] = 3.5, 3.1, and 3.8, respectively; P = 0.01, 0.009, and 0.007, respectively) in multivariable Cox models in AA TNBCs but not White TNBCs. Furthermore, KIFC1 knockdown more severely impaired migration in AA TNBC cells than White TNBC cells. Collectively, these data suggest that nKIFC1 WI an independent biomarker of poor prognosis in AA TNBC patients, potentially due to the necessity of KIFC1 for migration in AA TNBC cells.

Amplified centrosomes may underlie aggressive disease course in pancreatic ductal adenocarcinoma

Centrosome amplification (CA), the presence of centrosomes that are abnormally numerous or enlarged, is a well-established driver of tumor initiation and progression associated with poor prognosis across a diversity of malignancies. Pancreatic ductal adenocarcinoma (PDAC) carries one of the most dismal prognoses of all cancer types. A majority of these tumors are characterized by numerical and structural centrosomal aberrations, but it is unknown how CA contributes to the disease and patient outcomes. In this study, we sought to determine whether CA was associated with worse clinical outcomes, poor prognostic indicators, markers of epithelial-mesenchymal transition (EMT), and ethnicity in PDAC. We also evaluated whether CA could precipitate more aggressive phenotypes in a panel of cultured PDAC cell lines. Using publicly available microarray data, we found that increased expression of genes whose dysregulation promotes CA was associated with worse overall survival and increased EMT marker expression in PDAC. Quantitative analysis of centrosomal profiles in PDAC cell lines and tissue sections uncovered varying levels of CA, and the expression of CA markers was associated with the expression of EMT markers. We induced CA in PDAC cells and found that CA empowered them with enhanced invasive and migratory capabilities. In addition, we discovered that PDACs from African American (AA) patients exhibited a greater extent of both numerical and structural CA than PDACs from European American (EA) patients. Taken together, these findings suggest that CA may fuel a more aggressive disease course in PDAC patients.

A centrosome clustering protein, KIFC1, predicts aggressive disease course in serous ovarian adenocarcinomas

BACKGROUND

Amplified centrosomes are widely recognized as a hallmark of cancer. Although supernumerary centrosomes would be expected to compromise cell viability by yielding multipolar spindles that results in death-inducing aneuploidy, cancer cells suppress multipolarity by clustering their extra centrosomes. Thus, cancer cells, with the aid of clustering mechanisms, maintain pseudobipolar spindle phenotypes that are associated with low-grade aneuploidy, an edge to their survival. KIFC1, a nonessential minus end-directed motor of the kinesin-14 family, is a centrosome clustering molecule, essential for viability of extra centrosome-bearing cancer cells. Given that ovarian cancers robustly display amplified centrosomes, we examined the overexpression of KIFC1 in human ovarian tumors.

RESULTS

We found that in clinical epithelial ovarian cancer (EOC) samples, an expression level of KIFC1 was significantly higher when compared to normal tissues. KIFC1 expression also increased with tumor grade. Our In silico analyses showed that higher KIFC1 expression was associated with poor overall survival (OS) in serous ovarian adenocarcinoma (SOC) patients suggesting that an aggressive disease course in ovarian adenocarcinoma patients can be attributed to high KIFC1 levels. Also, gene expression levels of KIFC1 in high-grade serous ovarian carcinoma (HGSOC) highly correlated with expression of genes driving centrosome amplification (CA), as examined in publically-available databases. The pathway analysis results indicated that the genes overexpressed in KIFC1 high group were associated with processes like regulation of the cell cycle and cell proliferation. In addition, when we performed gene set enrichment analysis (GSEA) for identifying the gene ontologies associated to KIFC1 high group, we found that the first 100 genes enriched in KIFC1 high group were from centrosome components, mitotic cell cycle, and microtubule-based processes. Results from in vitro experiments on well-established in vitro models of HGSOC (OVSAHO, KURAMOCHI), OVCAR3 and SKOV3) revealed that they display robust centrosome amplification and expression levels of KIFC1 was directly associated (inversely correlated) to the status of multipolar mitosis. This association of KIFC1 and centrosome amplification with HGSOC might be able to explain the increased aggressiveness in this disease.

CONCLUSION

These findings compellingly underscore that KIFC1 can be a biomarker that predicts an aggressive disease course in ovarian adenocarcinomas.

Rampant centrosome amplification underlies more aggressive disease course of triple negative breast cancers

Centrosome amplification (CA), a cell-biological trait, characterizes pre-neoplastic and pre-invasive lesions and is associated with tumor aggressiveness. Recent studies suggest that CA leads to malignant transformation and promotes invasion in mammary epithelial cells. Triple negative breast cancer (TNBC), a histologically-aggressive subtype shows high recurrence, metastases, and mortality rates. Since TNBC and non-TNBC follow variable kinetics of metastatic progression, they constitute a novel test bed to explore if severity and nature of CA can distinguish them apart. We quantitatively assessed structural and numerical centrosomal aberrations for each patient sample in a large-cohort of grade-matched TNBC (n = 30) and non-TNBC (n = 98) cases employing multi-color confocal imaging. Our data establish differences in incidence and severity of CA between TNBC and non-TNBC cell lines and clinical specimens. We found strong correlation between CA and aggressiveness markers associated with metastasis in 20 pairs of grade-matched TNBC and non-TNBC specimens (p < 0.02). Time-lapse imaging of MDA-MB-231 cells harboring amplified centrosomes demonstrated enhanced migratory ability. Our study bridges a vital knowledge gap by pinpointing that CA underlies breast cancer aggressiveness. This previously unrecognized organellar inequality at the centrosome level may allow early-risk prediction and explain higher tumor aggressiveness and mortality rates in TNBC patients.