MARCH2, a Novel Oncogene-regulated SNAIL E3 Ligase, Suppresses Triple-negative Breast Cancer Metastases

Epithelial-mesenchymal transition (EMT) in cancer promotes metastasis and chemotherapy resistance. A subset of triple-negative breast cancer (TNBC) exhibits a mesenchymal gene signature that is associated with poor patient outcomes. We previously identified PTK6 tyrosine kinase as an oncogenic driver of EMT in a subset of TNBC. PTK6 induces EMT by stabilizing SNAIL, a key EMT-initiating transcriptional factor. Inhibition of PTK6 activity reverses mesenchymal features of TNBC cells and suppresses their metastases by promoting SNAIL degradation via a novel mechanism. In the current study, we identify membrane-associated RING-CH2 (MARCH2) as a novel PTK6-regulated E3 ligase that promotes the ubiquitination and degradation of SNAIL protein. The MARCH2 RING domain is critical for SNAIL ubiquitination and subsequent degradation. PTK6 inhibition promotes the interaction of MARCH2 with SNAIL. Overexpression of MARCH2 exhibits tumor suppressive properties and phenocopies the effects of SNAIL downregulation and PTK6 inhibition in TNBC cells, such as inhibition of migration, anoikis resistance, and metastasis. Consistent with this, higher levels of MARCH2 expression in breast and other cancers are associated with better prognosis. We have identified MARCH2 as a novel SNAIL E3 ligase that regulates EMT and metastases of mesenchymal TNBC.

SIGNIFICANCE

EMT is a process directly linked to drug resistance and metastasis of cancer cells. We identified MARCH2 as a novel regulator of SNAIL, a key EMT driver, that promotes SNAIL ubiquitination and degradation in TNBC cells. MARCH2 is oncogene regulated and inhibits growth and metastasis of TNBC. These insights could contribute to novel strategies to therapeutically target TNBC.

Impact of Preoperative Extramammary Findings in Patients with Newly Diagnosed Breast Cancer

BACKGROUND

Breast MRI has been associated with significant rates of false positive findings. We aimed to determine the frequency of extramammary findings (EMFs) in newly diagnosed breast cancer patients on breast MRI with contrast and assess the significance of these findings and need for additional imaging and follow-up.

STUDY DESIGN

A retrospective review of patients diagnosed with breast cancer from October 2018 to October 2019 was performed. Clinicopathologic features were collected, including type of breast cancer, size, stage, and whether the patients had a breast MRI. Those who had MRI were included, and the MRI was reviewed to determine if EMFs were identified. Further imaging and follow-up were assessed and recorded.

RESULTS

Of the 480 patients included in this cohort, 353 (74%) had invasive cancer, and the remainder had ductal carcinoma in situ. Two hundred ninety patients (60%) underwent MRI, and 53 of 290 (18%) had EMFs on MRI. Of these, 28 of 53 (53%) underwent additional imaging to further evaluate findings. Two invasive procedures were performed (fine needle aspiration and thymectomy), and 1 malignancy was identified in the thymus. No metastatic breast cancer was identified in any patient.

CONCLUSIONS

MRIs are frequently obtained for newly diagnosed breast cancer patients, and additional findings, especially extramammary, can be stressful for patients, and potentially lead to treatment delay if further evaluation is warranted. Our results demonstrate that incidental EMFs discovered via breast MRI are common and often lead to additional imaging studies. However, no metastatic lesions were found, and only 1 separate malignancy was identified, which did not affect breast cancer management. In patients with early-stage breast cancer, EMFs yield a very low rate of malignancy, providing high levels of reassurance and supporting the option of proceeding with surgery or treatment without delay.

Abstract P5-07-02: Embryo utilization in young breast cancer patients who have undergone egg harvesting for fertility preservation

INTRODUCTION: Much progress has been made related to fertility preservation in women diagnosed with breast cancer. This includes heightened awareness of impaired fertility due to breast cancer treatment, increased referrals to fertility specialists and development of safe and expeditious means of egg harvesting. Nevertheless, there has been limited investigation of the ultimate issue in fertility preservation, namely the frequency with which women who have undergone egg harvesting actually pursue childbearing. We have retrospectively reviewed a single institution’s experience with egg and embryo utilization among patients who expressly desired childbearing and underwent egg harvesting after a diagnosis of breast cancer. These issues have also been analyzed relative to race and insurance coverage. METHODS: In an IRB approved study, breast cancer patients treated in our institution between 2010 and 2020 were identified and their post-diagnosis fertility and childbearing history was reviewed. Inclusion criteria were age at presentation ≤ 45 years and diagnosis of either invasive breast cancer or ductal carcinoma in situ. Race (self-reported on clinic intake form) and insurance coverage data were analyzed. In cases of incomplete medical record data, we interviewed patients by telephone. RESULTS: 316 breast cancer patients of reproductive age were identified (average age at diagnosis = 39 years, range: 23 - 45). Of these, 168 patients (53%) were offered fertility referral and 118 (38%) saw a fertility specialist. 91 patients (29%) pursued egg harvesting followed by cryopreservation of eggs in 49 cases and embryos in 41 with 1 case unknown. Over an average of 5 years of follow-up (range: 2 - 12 years), 28 women (31% of those who pursued egg harvesting) utilized the egg or embryo to pursue childbearing. 17 underwent embryo transfer to themselves and 11 used surrogate carriers. To date, this has resulted in 20 childbirths from 24 pregnancies. Four pregnancies are currently ongoing and 1 woman is awaiting embryo transfer. Four patients who had undergone egg harvesting conceived without fertility intervention. Of the 55 Medicaid patients of reproductive age diagnosed with breast cancer, only 8 (15%) met with a fertility specialist, 4 harvested eggs, and none pursued childbearing. HMO/PPO insured patients were significantly more likely than Medicaid patients to pursue egg harvesting and embryo utilization (X2 = 7.320, df = 2, p = 0.026). Of 260 HMO/PPO insured patients, 110 (42%) met with a fertility expert, 87 harvested eggs and 28 pursued embryo transfer. Due to the small sample size of patients who utilized embryos in each racial subgroup, analysis did not yield statistically significant differences across groups (p=0.067). Nevertheless, apparent racial disparities exist. Our data reveal that 5 of 17 (29%) Asian patients and 22 of 62 (36%) White patients utilized embryos as opposed to Black patients (1/4 or 25%), Hispanic patients (0/4 or 0%) and those who identified their race as “other” (1/4 or 25%). CONCLUSIONS: These data demonstrate a low overall rate of cryopreserved egg and embryo utilization among women treated for breast cancer whose earlier pursuit of egg harvesting was evidence of a desire for childbearing. Furthermore, racial and insurance data demonstrate disparities in the pursuit of fertility treatment and utilization of preserved eggs and embryos. Further research will utilize interviews to analyze individual women’s decision-making process relevant to such issues as hormone therapy utilization, concerns about breast cancer recurrence, progression of disease and restraints imposed by relationship status and finances. Given the disparity findings reported here, finances will likely emerge as a significant barrier to childbearing in future qualitative research.

Citation Format: Christina Weltz, Daniella Nevid, Alison Pruzan, Elisa Port, Ronald Couri. Embryo utilization in young breast cancer patients who have undergone egg harvesting for fertility preservation [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 P5-07-02.

Insulin resistance and racial disparities in breast cancer prognosis: a multi-center cohort study

The survival for breast cancer (BC) is improving but remains lower in Black women than White women. A number of factors potentially drive the racial differences in BC outcomes. The aim of our study was to determine if insulin resistance (defined as homeostatic model assessment for insulin resistance (HOMA-IR)), mediated part of the relationship between race and BC prognosis (defined by the improved Nottingham prognostic index (iNPI)). We performed a cross-sectional study, recruiting self-identified Black and White women with newly diagnosed primary invasive BC from 10 US hospitals between March 2013 and February 2020. Survey, anthropometric, laboratory, and tumor pathology data were gathered, and we compared the results between Black and White women. We calculated HOMA-IR as well as iNPI scores and examined the associations between HOMA-IR and iNPI. After exclusions, the final cohort was 1206: 911 (76%) White and 295 (24%) Black women. Metabolic syndrome and insulin resistance were more common in Black than White women. Black women had less lobular BC, three times more triple-negative BC, and BCs with higher stage and iNPI scores than White women (P < 0.001 for all comparisons). Fewer Black women had BC genetic testing performed. HOMA-IR mediated part of the association between race and iNPI, particularly in BCs that carried a good prognosis and were hormone receptor (HR)-positive. Higher HOMA-IR scores were associated with progesterone receptor-negative BC in White women but not Black women. Overall, our results suggest that HOMA-IR contributes to the racial disparities in BC outcomes, particularly for women with HR-positive BCs.

Racial Disparities in Time to Treatment Persist in the Setting of a Comprehensive Breast Center

BACKGROUND

Racial disparities in breast cancer care have been linked to treatment delays. We explored whether receiving care at a comprehensive breast center could mitigate disparities in time to treatment.

METHODS

Retrospective chart review identified breast cancer patients who underwent surgery from 2012 to 2018 at a comprehensive breast center. Time-to-treatment intervals were compared among self-identified racial and ethnic groups by negative binomial regression models.

RESULTS

Overall, 2094 women met the inclusion criteria: 1242 (59%) White, 262 (13%) Black, 302 (14%) Hispanic, 105 (5%) Asian, and 183 (9%) other race or ethnicity. Black and Hispanic patients more often had Medicaid insurance, higher American Society of Anesthesiologists (ASA) scores, advanced-stage breast cancer, mastectomy, and additional imaging after breast center presentation (p < 0.05). After controlling for other variables, racial or ethnic minority groups had consistently longer intervals to treatment, with Black women experiencing the greatest disparity (incidence rate ratio 1.42). Time from initial comprehensive breast center visit to treatment was also significantly shorter in White patients versus non-White patients (p < 0.0001). Black race, Medicaid insurance/being uninsured, older age, earlier stage, higher ASA score, undergoing mastectomy, having reconstruction, and requiring additional pretreatment work-up were associated with a longer time from initial visit at the comprehensive breast center to treatment on multivariable analysis (p < 0.05).

CONCLUSION

Racial or ethnic minority groups have significant delays in treatment even when receiving care at a comprehensive breast center. Influential factors include insurance delays and necessity of additional pretreatment work-up. Specific policies are needed to address system barriers in treatment access.

Impact of Screening Mammography on Treatment in Young Women Diagnosed with Breast Cancer

BACKGROUND

There is little data exploring the impact of screening mammography on subsequent treatment in the 40-49-year age group with breast cancer. We sought to assess the association between frequency of mammography in young women and extent of surgery and chemotherapy required.

METHODS

An IRB-approved retrospective review was performed of patients diagnosed with breast cancer between ages 40 and 49 years from 1 January 2010 to 19 November 2018 within a single health system. Patients were grouped based on last screening 1-24 months prior to diagnosis (1-24 group), > 25 months prior to diagnosis (> 25 group), never screened, and > 25+ never screened (combination group). Multivariate logistic regression models were used to assess for associations between screening intervals and tumor and nodal stage, chemotherapy use, and extent of surgery.

RESULTS

Of 869 patients included for analysis, 20% were never screened, 60% screened 1-24 months, and 19% screened > 25 months prior to diagnosis. Compared with the 1-24 months group, the never-screened group, > 25 months group, and combined group were more likely to receive chemotherapy. The never-screened and combined groups were more likely to undergo mastectomy and/or axillary lymph node dissection. Of patients undergoing upfront surgery, the > 25 months and combined groups were more likely to receive adjuvant chemotherapy, while the never-screened and combined groups were more likely to have nodal disease.

CONCLUSION

Our findings support the initiation of screening mammography at age 40 years to reduce the risk of aggressive treatments for newly diagnosed breast cancers in this group.

Choice of Mastectomy May Increase the Extent of Axillary Surgery in Women with Breast Cancer

INTRODUCTION

Based on the ACOSOG Z0011 trial, women who undergo breast conservation therapy (BCT) and have limited disease in the axilla on sentinel lymph node (SLN) biopsy do not require axillary lymph node dissection (ALND). In this study we investigate the incidence of ALND in patients undergoing elective mastectomy with limited disease in the axilla to identify how many women may have been spared additional axillary surgery if they chose BCT.

METHODS

All women with invasive breast cancer treated at a single tertiary care breast center from 2010-2018 who were candidates for BCT but elected mastectomy and underwent SLN biopsy were identified through retrospective review of a prospectively maintained database. The primary outcome of interest was the incidence of ALND in women found to have a limited burden of disease in the axilla (1-2 positive SLNs).

RESULTS

The study population comprised 151 patients with invasive breast cancer eligible for BCT who chose mastectomy. On final pathology, 34 patients had 1-2 positive SLNs, and 16 of these patients underwent completion ALND. These 16 patients out of 151 overall lumpectomy candidates electing mastectomy (10.6%) could have been spared ALND if they did not elect mastectomy.

DISCUSSION

BCT candidates electing mastectomy have a 10.6% chance of undergoing more extensive axillary surgery than would have been recommended with BCT alone. The increased risk of undergoing additional axillary surgery should be incorporated into the preoperative discussion for patients choosing between BCT and mastectomy.

Does previous history of cancer or atypia predict histologic upgrade for pure intraductal papillomas diagnosed via core biopsy? A study of 490 cases at a single institution

BACKGROUND

Management of pure intraductal papillomas (IDP) without atypia diagnosed on core needle biopsy (CNB) remains controversial given highly variable rates of upgrade in the literature.

AIM

We sought to identify clinical and histologic factors that predict upgrade to atypia or malignancy in a large population.

METHODS AND RESULTS

A retrospective review was performed of all cases of pure IDP diagnosed on CNB and then surgically excised at a single institution from 2008 to 2018. Clinical, radiologic, and pathologic factors were compared in the no upgrade, upgrade to atypia, or upgrade to cancer groups. Univariate analysis was performed comparing no upgrade and upgrade to cancer or atypia. Four hundred and thirty nine patients were identified with a total of 490 IDP and a median age of 50 years (range 16-85). Of these patients, 54 (12.3%) were upgraded to atypia after surgical excision and five (1.1%) were upgraded to cancer. The presence of multiple papillomas in a single patient was a significant predictor of upgrade to cancer or atypia (p < .01), as well as age over ≥55 years (p < .01) and a prior history of cancer (p < .01). No other clinical, radiologic and histologic factors were found to be significant predictors of upgrade. 40/439 (9.1%) patients in the total cohort had prior history of cancer, and of these, 2/40 (5%) were found to have a new cancer after excision.

CONCLUSIONS

In patients with pure IDP on CNB, the upgrade rate to malignancy was 1.1%, while 12.3% were upgraded to atypia. The clinical significance of identifying atypia in a papilloma is unknown, especially in a patient with a prior history of atypia or cancer. However, the majority of patients who were upgraded to either atypia or cancer had no prior history of high-risk or malignant breast disease and are therefore considered true clinical upgrades. As such excision for IDP should be considered.

Surgical Risk Reduction, Breast Cancer and Childbearing

Purpose of Review

Young women who carry a genetic predisposition to breast cancer need to balance surgical and nonsurgical risk reducing options with childbearing. In this review, we explore how women make decisions without the benefit of official guidelines and in the context of frequently contradictory strategies.

Recent Findings

Women of reproductive age with known BRCA mutations receive incomplete and conflicting advice regarding the urgency and timing of risk reducing mastectomy (RRM). Those who prioritize RRM achieve highly effective prevention and thereby avoid not only a diagnosis of breast cancer but also adjuvant therapies which limit future childbearing. All reconstructive options are available and high levels of satisfaction are reported. Those who delay prophylactic mastectomy can pursue nonsurgical breast and ovarian risk reduction strategies such as tamoxifen and oral contraception, yet these delay child bearing. Women who prioritize child bearing maintain the ability to breast feed but have limited screening options during pregnancy and lactation.

Summary

Prioritization and timing of risk reduction and childbearing in young BRCA positive women is challenging. Elucidating these challenges enables clinicians to better counsel these women.

Association of Insulin Resistance and Higher Oncotype DX™ Recurrence Score

BACKGROUND

Black women with breast cancer have a worse overall survival compared with White women; however, no difference in Oncotype DX™ (ODX) recurrence scores has been observed to explain this health disparity. Black women are also disproportionately affected by insulin resistance. We evaluated whether insulin resistance is associated with a higher ODX recurrence score and whether there is a difference between White and Black women to explain disparate clinical outcomes.

METHODS

A subgroup analysis of patients in a multi-institutional cross-sectional study evaluating differences in insulin resistance between White and Black women was performed. Women diagnosed with a new hormone receptor-positive, HER2/neu-negative breast cancer with an ODX recurrence score were identified. Fasting blood glucose and insulin measurements were used to calculate the homeostatic model assessment of insulin resistance (HOMA-IR) score, a method for assessing insulin resistance, and compared against ODX scores.

RESULTS

Overall, 412 women (358 White women, 54 Black women) were identified. Compared with White women, Black women had a higher body mass index (30 vs. 26 kg/m², p < 0.0001), higher HOMA-IR score (2.4 vs. 1.4, p = 0.004), and more high-grade tumors (30% vs. 16%, p = 0.01). There was a direct positive association with an increasing ODX score and HOMA-IR (p = 0.014). On subset analysis, this relationship was seen in White women (p = 0.005), but not in Black women (p = 0.55).

CONCLUSION

In women with newly diagnosed breast cancer, increasing insulin resistance is associated with a higher recurrence score; however, this association was not present in Black women. This lack of association may be due to the small number of Black women in the cohort, or possibly a reflection of a different biological disease process of the patient's tumor.

Trends in neoadjuvant chemotherapy versus surgery-first in stage I HER2-positive breast cancer patients in the National Cancer DataBase (NCDB)

BACKGROUND

Neoadjuvant chemotherapy (NAC) is the standard of care for locally advanced HER2 + breast cancer (BC). Optimal sequencing of treatment (NAC vs. surgery first) is less clear cut in stage I (T1N0) HER2 + BC, where information from surgical pathology could impact adjuvant treatment decisions. Utilizing the NCDB, we evaluated the trend of NAC use compared to upfront surgery in patients with small HER2 + BC.

METHODS

We identified NCDB female patients diagnosed with T1 N0 HER2 + BC from 2010 through 2015. Prevalence ratios (PR) using multivariable robust Poisson regression models were calculated to measure the association between baseline characteristics and the receipt of NAC. Analysis of trends over time was denoted by annual percent change (APC) of NAC versus surgery upfront.

RESULTS

Of the 14,949 that received chemotherapy and anti-HER2 therapy during the study period, overall 1281 (8.6%) received NAC and 13,668 (91.4%) received adjuvant treatment. Patients receiving NAC increased annually from 4.2% in 2010 to 17.3% in 2015, with the most rapid increase occurring between years 2013 (8.5%) and 2014 (14.2%). The greatest increase was seen in patients with cT1c tumors with an APC of 37.8% over the study period (95% CI 29.0, 47.3%, p < 0.01), although a significant trend was likewise seen in patients with cT1a (APC = 26.1%,95% CI 1.59, 56.6%), and cT1b (APC = 27.4%, 95% CI 18.0, 37.7%) tumors. Predictors of neoadjuvant therapy receipt were age younger than 50 (PR = 1.69, 95% CI 1.52, 1.89), Mountain/Pacific area (PR = 1.24, 95% CI 1.05, 1.46), and estrogen receptor negativity (ER- PR + : PR = 2.01, 95% CI 1.51, 2.68; ER- PR- : PR = 1.49, 95% CI 1.32, 1.69).

CONCLUSIONS

Neoadjuvant therapy for T1 N0 HER2 + BC increased over the study period and was mostly due increased use in clinical T1c tumors. This may be consistent with secular change in Pertuzumab treatment following FDA approval in 2013.

Response in breast vs axilla after neoadjuvant treatment and implications for nonoperative management of invasive breast cancer

Improved imaging and neoadjuvant chemotherapy (NAT) have led to higher pathologic complete response rates (pCR) in patients with invasive breast cancer. This has questioned the necessity of surgery and axillary lymph node (ALN) dissection in these patients. Prospective clinical trials are implementing extensive core biopsies of the tumor bed of patients with clinical complete response as a means to identify and spare them breast surgery. In addition, it is anticipated that patients with pCR are most likely going to have no or minimal disease in ALN as well. To verify the feasibility of these trials, we performed a pathologic analysis of all our patients who have undergone NAT from 2009 to present. Using pathology data base, we identified 362 patients treated with neoadjuvant chemotherapy followed by surgery. Clinical and pathologic information including gross and microscopic descriptions as well as biomarker status was collected. pCR was 50% for patients with negative ALN pretreatment but only 28% for patients with positive ALN at diagnosis. Despite achieving pCR in the breast, up to 10% of patients with positive ALN and 1% with negative ALN had persistent disease. Eight percent of patients that were presumed to have no ALN disease either clinically and or by imaging were found to have metastatic carcinoma in ALN. The metastases were predominantly (80%) <5 mm, and not palpable on physical examination and or due to biopsy sampling error. pCR in breast and ALN directly correlated with tumor size, ALN disease, and Her2 positive and triple negative receptor phenotype. In breast cancer patients who are node positive at time of diagnosis with pCR in the breast after neoadjuvant chemotherapy, residual lymph node disease was very uncommon. Further study is warranted to select patients who may avoid breast and axillary surgery post neoadjuvant chemotherapy.

Adherence to NCCN Guidelines for Genetic Testing in Breast Cancer Patients: Who Are We Missing?

BACKGROUND

Genetic predisposition accounts for 5-10% of all breast cancers (BC) diagnosed. NCCN guidelines help providers identify appropriate candidates for counseling and testing. Concerns about underutilization of genetic testing have spurred interest in broader peri-diagnostic testing. We evaluated surgeon adherence to NCCN guidelines and studied patterns of testing in newly diagnosed BC patients.

METHODS

A total of 397 patients were identified with newly diagnosed BC treated at our institution between 2016 and 2017 with no prior genetic testing. Eligibility for genetic testing based on NCCN criteria, referral, and patient compliance were recorded.

RESULTS

In total, 212 of 397 (53%) met NCCN testing criteria. Fifty-nine of 212 (28%) patients went untested despite meeting one or more criteria. Fourteen of 59 (24%) of these were referred but did not comply. Most common criteria for meeting eligibility for testing both in the overall cohort and among missed patients were family history-based. Age > 45 years old and non-Ashkenazi Jewish descent were predictive of missed referral (p < 0.01). We identified pathogenic mutations in 16 of 153 (10%) patients who did undergo testing (11 (7%) BRCA1 or 2 and 5 (3%) with other predisposition gene mutations) or 16 of 397 (4%) among the overall group.

CONCLUSIONS

Our data highlight the underutilization of genetic testing. Even in the setting of a full-service breast center with readily available genetic counseling, there is a substantial miss rate for identifying eligible patients, related to assessment of family history, patient age, and ethnicity, as well as patient compliance. Broader peri-diagnostic testing should be considered, and higher compliance rates with patients referred should be sought.

Use of neoadjuvant versus adjuvant chemotherapy for hormone receptor-positive breast cancer: a National Cancer Database (NCDB) study

INTRODUCTION

Neoadjuvant chemotherapy (NAC) is a well-established therapeutic option for patients with locally advanced disease often allowing downstaging and facilitation of breast conserving therapy. With evolution of better targeted treatment regimens and awareness of improved outcomes for significant responders, use of NAC has expanded particularly for triple negative and HER2-positive (HER2+) breast cancer. In this study, we explore utility of neoadjuvant chemotherapy for hormone receptor-positive HER2-negative (HR+ HER2-) patients.

METHODS

Patients with HR+ HER2- breast cancer treated with chemotherapy before or after surgery were identified from 2010 to 2015 in the NCDB. Multivariable regression models adjusted for covariates were used to determine associations within these groups.

RESULTS

Among 134,574 patients (clinical stage 2A, 64%; 2B, 21%; 3, 15%), 105,324 (78%) had adjuvant chemotherapy (AC) and 29,250 (22%) received NAC. Use of NAC increased over time (2010-2015; 13.2-19.4% and PR = 1.34 for 2015; p < 0.0001). Patients were more likely to receive NAC with cT3, cT4, and cN+ disease. Patients less likely to receive NAC were age ≥ 50, lobular carcinoma, increased Charlson-Deyo score, and government insurance. Complete response (pCR) was noted in 8.3% of NAC patients. Axillary downstaging occurred in 21% of patients, and predictors included age < 50 years, black race, poorly differentiated grade, invasive ductal histology, and either ER or PR negativity.

CONCLUSIONS

NAC use among HR+ HER2- breast cancer patients has expanded over time and offers downstaging of disease for some patients, with pCR seen in only a small subset, but downstaging of the axilla in 21%. Further analysis is warranted to determine the subgroup of patients with HR+ HER2- disease who benefit from this approach.

Insulin resistance contributes to racial disparities in breast cancer prognosis in US women

Background

Racial disparities in breast cancer survival between Black and White women persist across all stages of breast cancer. The metabolic syndrome (MetS) of insulin resistance disproportionately affects more Black than White women. It has not been discerned if insulin resistance mediates the link between race and poor prognosis in breast cancer. We aimed to determine whether insulin resistance mediates in part the association between race and breast cancer prognosis, and if insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R) expression differs between tumors from Black and White women.

Methods

We conducted a cross-sectional, multi-center study across ten hospitals. Self-identified Black women and White women with newly diagnosed invasive breast cancer were recruited. The primary outcome was to determine if insulin resistance, which was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR), mediated the effect of race on prognosis using the multivariate linear mediation model. Demographic data, anthropometric measurements, and fasting blood were collected. Poor prognosis was defined as a Nottingham Prognostic Index (NPI) > 4.4. Breast cancer pathology specimens were evaluated for IR and IGF-1R expression by immunohistochemistry (IHC).

Results

Five hundred fifteen women were recruited (83% White, 17% Black). The MetS was more prevalent in Black women than in White women (40% vs 20%, p < 0.0001). HOMA-IR was higher in Black women than in White women (1.9 ± 1.2 vs 1.3 ± 1.4, p = 0.0005). Poor breast cancer prognosis was more prevalent in Black women than in White women (28% vs 15%. p = 0.004). HOMA-IR was positively associated with NPI score (r = 0.1, p = 0.02). The mediation model, adjusted for age, revealed that HOMA-IR significantly mediated the association between Black race and poor prognosis (β = 0.04, 95% CI 0.005–0.009, p = 0.002). IR expression was higher in tumors from Black women than in those from White women (79% vs 52%, p = 0.004), and greater IR/IGF-1R ratio was also associated with higher NPI score (IR/IGF-1R >  1: 4.2 ± 0.8 vs IR/IGF-1R = 1: 3.9 ± 0.8 vs IR/IGF-1R < 1: 3.5 ± 1.0, p < 0.0001).

Conclusions

In this multi-center, cross-sectional study of US women with newly diagnosed invasive breast cancer, insulin resistance is one factor mediating part of the association between race and poor prognosis in breast cancer.

Abstract P5-01-09: Prospective genomic and PD-L1 profiling of patients with residual triple negative breast cancer after neoadjuvant chemotherapy

Background/Rationale: Sensitivity to chemotherapy consistently remains a strong predictor of long term outcomes and survival for patients diagnosed with triple negative breast cancer (TNBC). Patients who do not achieve a complete pathological response to pre-operative, neoadjuvant chemotherapy are at increased risk for metastatic recurrence. Clinical trials with targeted therapies and immunotherapies aim to reduce this risk of recurrence for this patient population. As part of our ongoing prospective study of patients with TNBC that involves serial blood collections and tissue collections (pre-treatment biopsy and post-neoadjuvant surgical specimen) from the time of initial diagnosis, we are particularly focused on those patients with residual disease following neoadjuvant treatment. Comprehensive tissue and cell-free DNA (cfDNA)/circulating tumor cell (CTC) profiling of these patients could lead to insights into mechanisms of chemotherapy resistance and new treatment strategies to prevent recurrences. In addition to genomic profiling, we have analyzed PD-L1 expression on tissue and CTC’s which may contribute to improve targeted utilization of immunotherapies for patients with early stage, high-risk TNBC. Methods: Patients diagnosed with TNBC (stage 1-3) are consented for this prospective study. Serial collections of blood are obtained at time of initial diagnosis, following neoadjuvant chemotherapy or upfront surgery and at 6 month intervals following completion of all active therapy. cfDNA/CTC are isolated using Cynvenio’s Liquid Biopsy platform and sequenced on a rolling basis with Oncomine V3 panel. Tissue from initial biopsy and surgical resection are also collected and sequenced. PD-L1 staining of breast tumor tissue and CTC is performed using antibody SP-142 and atezolizumab, respectively. Clinical outcomes (response to chemotherapy and recurrence data) are also recorded. Results: 30 patients are currently being followed. Of these 24 patients were treated with neoadjuvant chemotherapy and 10/24 (42%) had a pathological complete response (pCR). For the patients treated with neoadjuvant chemotherapy whose pre-treatment samples have been sequenced, 3/6 (50%) of patients who did not achieve a pCR had pre-treatment detectable mutations in cfDNA/CTC in contrast to 3/9 (33%) patients who achieved a pCR. Furthermore, all 6 patients who had residual disease had at least one blood collection with detectable cfDNA/CTC mutations following completion of all active breast cancer therapy. For the five patients with post-neoadjuvant residual disease whose surgical specimens have been stained for PD-L1 expression, 4/5 (80%) are PD-L1 positive (&gt;1%) either in the tumor or infiltrating leukocyte population. PD-L1 positive circulating CTC’s were also detected in 1 of these patients with PD-L1 positive residual disease thus far. Conclusions: Prospective serial analysis of cfDNA/CTC may identify patients who are at higher risk for incomplete response to neoadjuvant therapy or metastatic recurrence. PD-L1 staining of post-neoadjuvant residual cancer and/or CTC’s may help identify high risk patients most likely to benefit from adjuvant immunotherapy.

Citation Format: Hanna Yoko Irie, Paul Schmidt, Elisa Port, Natalie Berger, Paula Klein, Yayoi Kinoshita, Alan Soto, Kereeti Pisapati, Ronald Couri, Olivia Kolodka, Hanane Arib, Robert Sebra, Michael J Donovan. Prospective genomic and PD-L1 profiling of patients with residual triple negative breast cancer after neoadjuvant chemotherapy [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 P5-01-09.

Practice Changing Potential of TAILORx: A Retrospective Review of the National Cancer Data Base from 2010 to 2015

BACKGROUND

Uncertainty regarding chemotherapy benefit among breast cancer patients with intermediate Oncotype Dx^® recurrence scores (RS; 11-25) led to the TAILORx study. We evaluated chemotherapy use in patients with intermediate RS to determine practice change potential based on the TAILORx results.

METHODS

National Cancer Data Base patients with hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative, N0 breast cancer were identified and were divided into three groups: Group A, ≤ 50 years of age (RS 11-15); Group B, ≤ 50 years of age (RS 16-25); and Group C, > 50 years of age (RS 11-25). Demographic and clinical factors were compared using Chi square tests and Poisson regression models to determine predictors of chemotherapy receipt.

RESULTS

Overall, 37,087 patients met the inclusion criteria, with 6.3% in Group A and 11.7% in Group C having received chemotherapy that may have been avoided based on TAILORx. The majority of Group B (64.7%) did not receive chemotherapy, whereas TAILORx showed potential benefit from treatment. Chemotherapy use decreased over time for all intermediate RS patients. T2 tumors, high grade, and treatment before 2012 increased the likelihood of chemotherapy receipt among both groups. Younger patients with the lower intermediate RS (Group A) were more likely to receive chemotherapy if they had treatment at community or comprehensive centers, whereas moderate grade was also a significant factor to receive chemotherapy in Group B. Significant factors in older patients (Group C) were Black race, estrogen receptor-positive/progesterone receptor-negative, and moderate/high grade.

CONCLUSIONS

The most potential impact of TAILORx findings on practice change is for patients ≤ 50 years of age with RS of 16-25 who did not receive chemotherapy but may benefit. These findings may serve as a baseline for future analysis of practice patterns related to TAILORx.

The effect of modifiable risk factors on breast cancer aggressiveness among black and white women

INTRODUCTION

Although breast cancer incidence is higher among white women, black women are more likely to have aggressive tumors with less favorable histology, and to have a worse prognosis. Obesity and alcohol consumption have been identified as two modifiable risk factors for breast cancer, while physical activity may offer protection. Little however is known about the association of these factors with race on the severity of breast cancer.

METHODS

Data collected as part of a large prospective study looking at insulin resistance and race among women with breast cancer was queried for patient characteristics, lifestyle factors and tumor characteristics. The association with Nottingham Prognostic Index (NPI) was assessed with different models using univariate and multivariate linear regression.

RESULTS

Among 746 women in our cohort, 82% (n = 615) were white and 18% (n = 131) were black, mean age 58 years. Black patients were more likely to have high BMI (31.0 vs. 26.7, p < 0.0001), comorbidities (69% vs 55%, p = 0.01), self-reported poor diet (70% vs 42%, p < 0.001), be sedentary (56% vs 46%, p = 0.03) and were less likely to consume alcohol (8% vs 32%, p < 0.0001) compared to white patients. Overall, 137 (18%) of the patients had poorer prognosis (NPI > 4.4), which was significantly associated with younger age (55.6 vs 58.5 years, p = 0.02), black race (27% vs 15%, p = 0.001), triple negative cancer (15% vs 6%, p = 0.003), and poor diet (54% vs 45%, p = 0.046) compared to patients with better prognosis (NPI ≤ 4.4). On multivariate analysis, (model R² = 0.12; p < 0.001), age (β = -0.011 per year, p = 0.002), healthy diet (β = -0.195, p = 0.02), and exercise (β = -0.004, p = 0.02) were associated with better prognosis, while black race (β = 0.247, p = 0.02) and triple negative cancer (β = 0.908, p < 0.0001) were associated with poor prognosis. Neither alcohol use nor BMI was significantly associated with NPI.

CONCLUSION

Among modifiable risk factors, diet and exercise are associated with NPI. Unmodifiable factors including race and biologic subtype remain the most important determinants of prognosis.

The Evolving and Multidisciplinary Considerations in Nodal Radiation in Breast Cancer

The therapeutic management of regional lymph nodes in breast cancer has seen a remarkable change in the past 2 decades. Clinical trials have refined our knowledge regarding the biology of the disease including the prognostic significance of disease in the regional lymph nodes. The contemporary management of lymph nodes is also influenced by advances in surgical technique, radiation oncology delivery systems, and effective systemic therapy regimens. This paper describes the role of regional nodal irradiation in the context of the de-escalation of axillary surgery, improved understanding of the molecular and pathologic features, and increasing use of neoadjuvant chemotherapy.

Defining the Need for Imaging and Biopsy After Mastectomy

BACKGROUND

The proportion of patients eligible for breast-conservation therapy (BCT) yet opting for mastectomy is increasing. This decision is often driven by the desire to eliminate future screening and/or biopsy of the remaining breast or breasts. This study investigated the incidence of post-mastectomy imaging and biopsy.

METHODS

A retrospective review of all unilateral mastectomy (UM) and bilateral mastectomy (BM) cases managed at a single institution was undertaken. Post-mastectomy imaging and biopsy rates were determined.

RESULTS

Between 2009 and 2015, 185 UM and 200 BM cases managed for breast cancer were identified. The mean follow-up period was 30 months (range 3-75 months). For the patients with UM, imaging studies and biopsies done on the contralateral side were excluded given the standard of care for continued surveillance of the contralateral breast. Of the 185 UM patients, 19 (10%) underwent ipsilateral imaging (all ultrasounds) for physical examination findings, 11 (6%) underwent biopsy, and 2 (1%) had malignant findings. Of the 200 BM patients, 31 (15.5%) required imaging (29 ultrasounds and 2 MRIs), with 76% of the ultrasounds performed on the side with previous cancer. Subsequently, 16 (8%) of the BM patients had biopsy, with 11 (69%) of the 16 biopsies performed on the ipsilateral side. Three (1.5%) of the biopsies done on ipsilateral side demonstrated malignancy, whereas all the contralateral biopsies were benign.

CONCLUSIONS

For 10-15.5% of patients who undergo mastectomy, either UM or BM, subsequent imaging is required, whereas 6-8% undergo biopsy. The yield of malignancy is low, approximately 1%. Thus, after mastectomy, the need for imaging and biopsy is not eliminated. This information is critical for patient understanding and expectation related to surgical decision making.

Who Is Ordering MRIs in Newly Diagnosed Breast Cancer Patients?

The role of MRI in the workup of newly diagnosed breast cancer patients remains controversial. Breast MRI detects additional disease, but this has not translated into improved outcomes. In light of a dramatic rise in MRI use, we investigated patterns of MRI ordering for newly diagnosed breast cancer. All newly diagnosed breast cancer cases presenting for surgical management to a specialized breast center from 2011 to 2013 were reviewed. Patients who had an MRI ordered by their operating surgeon were compared with those who had an MRI completed previously. Of 1037 patients, 504 (49%) with newly diagnosed breast cancer underwent MRI as part of their pre-operative evaluation. Variables associated with MRI use included commercial insurance, increased breast density, genetic testing, mamographically occult disease, and lobular pathology. Of women who presented to our center with an MRI already completed, 63 per cent were ordered by a primary care provider. Of the 504 patients, 233 (44%) who had an MRI underwent an additional biopsy, and 166 (33%) had a resultant change in management. There was no significant difference in MRI-directed change in patient care depending on ordering provider. Further research is needed to develop evidence-based guidelines for preoperative MRI evaluation to optimize patient outcomes.

Who Is Ordering MRIs in Newly Diagnosed Breast Cancer Patients?

The role of MRI in the workup of newly diagnosed breast cancer patients remains controversial. Breast MRI detects additional disease, but this has not translated into improved outcomes. In light of a dramatic rise in MRI use, we investigated patterns of MRI ordering for newly diagnosed breast cancer. All newly diagnosed breast cancer cases presenting for surgical management to a specialized breast center from 2011 to 2013 were reviewed. Patients who had an MRI ordered by their operating surgeon were compared with those who had an MRI completed previously. Of 1037 patients, 504 (49%) with newly diagnosed breast cancer underwent MRI as part of their preoperative evaluation. Variables associated with MRI use included commercial insurance, increased breast density, genetic testing, mamographically occult disease, and lobular pathology. Of women who presented to our center with an MRI already completed, 63 per cent were ordered by a primary care provider. Of the 504 patients, 233 (44%) who had an MRI underwent an additional biopsy, and 166 (33%) had a resultant change in management. There was no significant difference in MRI-directed change in patient care depending on ordering provider. Further research is needed to develop evidence-based guidelines for preoperative MRI evaluation to optimize patient outcomes.

Utility of surveillance MRI in women with a personal history of breast cancer

PURPOSE

To determine the utility and rate of biopsy in women with a positive history of breast cancer screened with MRI.

METHODS

Retrospective review of 491 breast MRI screening examinations in women with a personal history of breast cancer.

RESULTS

In total, 107 biopsies were performed, an average of 0.09 biopsies per person year. The positive predictive value for biopsies prompted by MRI findings was 0.24 (95% C.I. 0.10-0.38). Eight of the nine subsequent cancers were initially identified on screening MRI alone.

CONCLUSION

Surveillance MRI in breast cancer survivors may increase detection of subsequent cancers while increasing rate of biopsy.

Physician preference and patient satisfaction with radioactive seed versus wire localization

BACKGROUND

Nonpalpable breast lesions require localization before excision. This is most commonly performed with a wire (WL) or a radioactive seed (SL), which is placed into the breast under radiographic guidance. Although there are advantages of each modality, there are no guidelines to address which patients should undergo WL versus SL. We investigated factors influencing the selection of SL versus WL at our institution and assessed patient satisfaction with each procedure.

METHODS

Patients undergoing preoperative localization of nonpalpable breast lesions from May 2014 through August 2015 were included. Physicians were surveyed on surgical scheduling to evaluate factors influencing the decision to perform SL or WL. Patient satisfaction was evaluated with a survey at the first postoperative visit. Retrospective chart review was performed.

RESULTS

341 patients were included: 104 (30%) patients underwent SL and 237 (70%) underwent WL. There was no difference in patient age, benign versus malignant disease, or need for concomitant axillary surgery comparing the SL versus WL groups. Physician survey indicated that 18% of patients were candidates for WL only. Of the patients who were eligible for both, 88 (41%) ultimately underwent SL and 126 (59%) had WL. The most commonly cited reason for selection of one localization method or the other was physician preference, followed by patient preference or avoiding additional visit. There was no significant difference in self-reported preoperative anxiety level, convenience of the localization procedure, pain of the localization procedure, operative experience, postoperative pain level or medication requirement, or overall patient satisfaction comparing patients who underwent SL and WL.

CONCLUSIONS

SL and WL offer patients similar comfort and satisfaction. Factors influencing selection of one modality over the other include both logistic and clinical considerations.

Recurrent patterns of DNA copy number alterations in tumors reflect metabolic selection pressures

Copy number alteration (CNA) profiling of human tumors has revealed recurrent patterns of DNA amplifications and deletions across diverse cancer types. These patterns are suggestive of conserved selection pressures during tumor evolution but cannot be fully explained by known oncogenes and tumor suppressor genes. Using a pan-cancer analysis of CNA data from patient tumors and experimental systems, here we show that principal component analysis-defined CNA signatures are predictive of glycolytic phenotypes, including 18F-fluorodeoxy-glucose (FDG) avidity of patient tumors, and increased proliferation. The primary CNA signature is enriched for p53 mutations and is associated with glycolysis through coordinate amplification of glycolytic genes and other cancer-linked metabolic enzymes. A pan-cancer and cross-species comparison of CNAs highlighted 26 consistently altered DNA regions, containing 11 enzymes in the glycolysis pathway in addition to known cancer-driving genes. Furthermore, exogenous expression of hexokinase and enolase enzymes in an experimental immortalization system altered the subsequent copy number status of the corresponding endogenous loci, supporting the hypothesis that these metabolic genes act as drivers within the conserved CNA amplification regions. Taken together, these results demonstrate that metabolic stress acts as a selective pressure underlying the recurrent CNAs observed in human tumors, and further cast genomic instability as an enabling event in tumorigenesis and metabolic evolution.

Impact of neoadjuvant therapy on eligibility for and frequency of breast conservation in stage II-III HER2-positive breast cancer: surgical results of CALGB 40601 (Alliance)

OBJECTIVE

It had been previously shown that patients who receive neoadjuvant systemic therapy (NST) are more likely to undergo breast-conserving therapy (BCT) than those who have primary surgery. However, the frequency with which patients who are not BCT-eligible prior to NST convert to BCT-eligible with treatment is unknown. To document this conversion rate in a subset of patients expected to have a high clinical response rate to NST, we studied surgical assessment and management of patients enrolled on a randomized neoadjuvant trial for stage II-III HER2-positive breast cancer (HER2 + BC)(CALGB 40601).

METHODS

The treating surgeon assessed BCT candidacy based on clinico-radiographic criteria both before and after NST. Definitive breast surgical management was at surgeon and patient discretion. We sought to determine (1) the conversion rate from BCT-ineligible to BCT-eligible (2) the percentage of BCT-eligible patients who chose breast conservation, and (3) the rate of successful BCT. We also evaluated surgeon-determined factors for BCT-ineligibility and the correlation between BCT eligibility and pathologic complete response (pCR).

RESULTS

Of 292 patients with pre- and post-NST surgical assessments, 59 % were non-BCT candidates at baseline. Of the 43 % of these patients who converted with NST, 67 % opted for BCT, with an 80 % success rate. NST increased the BCT-eligible rate from 41 to 64 %. Common factors cited for BCT-ineligibility prior to NST including tumor size (56 %) and probable poor cosmetic outcome (26 %) were reduced by 67 and 75 %, respectively, with treatment, while multicentricity, the second most common factor (33 %), fell by only 16 %. Since 23 % of the BCT-eligible patients chose mastectomy, BCT was the final surgical procedure in just 40 % of the patients. Patients considered BCT-eligible both at baseline and after NST had a pCR rate of 55 %, while patients who were BCT-ineligible prior to NST had the same pCR rate (44 %) whether they converted to BCT-eligible or not.

CONCLUSIONS

Many patients with HER2 + BC deemed ineligible for BCT at baseline can be converted to BCT-eligible with NST; excluding patients with multicentric disease substantially increases that percentage. In converted patients who opt for BCT, the success rate is similar to that of patients considered BCT-eligible at baseline. Whether a BCT-ineligible patient converts to BCT eligibility or not does not appear to affect the likelihood of achieving a pCR. Despite the efficacy of NST in this patient cohort, only 40 % of patients had successful BCT; further research into why BCT-eligible patients often opt for mastectomy is needed.

Multiplexed immunofluorescence delineates proteomic cancer cell states associated with metabolism

The phenotypic diversity of cancer results from genetic and nongenetic factors. Most studies of cancer heterogeneity have focused on DNA alterations, as technologies for proteomic measurements in clinical specimen are currently less advanced. Here, we used a multiplexed immunofluorescence staining platform to measure the expression of 27 proteins at the single-cell level in formalin-fixed and paraffin-embedded samples from treatment-naive stage II/III human breast cancer. Unsupervised clustering of protein expression data from 638,577 tumor cells in 26 breast cancers identified 8 clusters of protein coexpression. In about one-third of breast cancers, over 95% of all neoplastic cells expressed a single protein coexpression cluster. The remaining tumors harbored tumor cells representing multiple protein coexpression clusters, either in a regional distribution or intermingled throughout the tumor. Tumor uptake of the radiotracer 18F-fluorodeoxyglucose was associated with protein expression clusters characterized by hormone receptor loss, PTEN alteration, and HER2 gene amplification. Our study demonstrates an approach to generate cellular heterogeneity metrics in routinely collected solid tumor specimens and integrate them with in vivo cancer phenotypes.

Abstract P3-06-31: Patient-derived xenografts accurately predict patient response in breast cancer patients

PURPOSE/OBJECTIVES: A growing body of evidence demonstrates that patient-derived xenografts (PDXs) represent living tumor models that accurately reflect the biology of the primary patient tumor. More importantly, we have previously shown that PDX models show responses to therapeutic agents that are concordant with patient clinical response and can be used to direct personalized cancer treatments (Stebbing, 2014). Here we report the ability of PDX models to predict for patient response to drug treatment in a cohort of breast cancer patients.

MATERIALS/METHODS: Tumors were resected from patients with either primary or metastatic breast cancer and implanted into immunodeficient mice to establish PDX models. Successfully engrafted PDX models were expanded and randomized for drug sensitivity testing. Tumor growth inhibition and tumor regression were captured and results were correlated with a patient’s clinical response. In some cases, PDX results were used to personalize cancer treatment and some patients used PDX-directed treatments over multiple lines of therapy.

RESULTS: A total of 42 tumors from 40 patients were implanted resulting in 21 successfully engrafted PDX models (50% engraftment rate). Notably, engraftment rates were much higher for patients with triple negative breast cancer (TNBC) and resulted in 7 successful PDX models from 8 TNBC patients (87.5% engraftment rate). Drug sensitivity testing was offered to patients with established PDX models. Drugs and drug combinations tested included standard and nonstandard chemotherapy as well as biologics. At that time of this publication, 4 patients (3 TNBC and 1 HER2+) with completed drug sensitivity tests also had clinical data available resulting in 7 clinical correlations; 4 retrospective and 3 prospective. In all 7 cases, the PDX model accurately predicted patient clinical response demonstrating an accuracy of 100%. Five of the drug tests predicted drug sensitivity and 2 tests predicted resistance, indicating the potential of the PDX platform to predict for both sensitivity and resistance to therapy. The 3 prospective correlations resulted in concordant clinical benefit in 2 patients for duration greater than 6 months each.

CONCLUSIONS: These data support the use of the personalized PDX model as a platform for therapeutic decision making that can guide treatment for patients with breast cancer. A prospective clinical trial in TNBC is currently underway.

Citation Format: Lisa Stow, Amanda Katz, Hanna Irie, Elisa Port, Justin Stebbing, Daniel Ciznadija, Angela Davies, Keren Paz. Patient-derived xenografts accurately predict patient response in breast cancer patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-31.

18F-fluorodeoxy-glucose positron emission tomography marks MYC-overexpressing human basal-like breast cancers

In contrast to normal cells, cancer cells avidly take up glucose and metabolize it to lactate even when oxygen is abundant, a phenomenon referred to as the Warburg effect. This fundamental alteration in glucose metabolism in cancer cells enables their specific detection by positron emission tomography (PET) following i.v. injection of the glucose analogue (18)F-fluorodeoxy-glucose ((18)FDG). However, this useful imaging technique is limited by the fact that not all cancers avidly take up FDG. To identify molecular determinants of (18)FDG retention, we interrogated the transcriptomes of human-cancer cell lines and primary tumors for metabolic pathways associated with (18)FDG radiotracer uptake. From ninety-five metabolic pathways that were interrogated, the glycolysis, and several glycolysis-related pathways (pentose phosphate, carbon fixation, aminoacyl-tRNA biosynthesis, one-carbon-pool by folate) showed the greatest transcriptional enrichment. This "FDG signature" predicted FDG uptake in breast cancer cell lines and overlapped with established gene expression signatures for the "basal-like" breast cancer subtype and MYC-induced tumorigenesis in mice. Human breast cancers with nuclear MYC staining and high RNA expression of MYC target genes showed high (18)FDG-PET uptake (P < 0.005). Presence of the FDG signature was similarly associated with MYC gene copy gain, increased MYC transcript levels, and elevated expression of metabolic MYC target genes in a human breast cancer genomic dataset. Together, our findings link clinical observations of glucose uptake with a pathologic and molecular subtype of human breast cancer. Furthermore, they suggest related approaches to derive molecular determinants of radiotracer retention for other PET-imaging probes.

18F-FDG PET of locally invasive breast cancer and association of estrogen receptor status with standardized uptake value: microarray and immunohistochemical analysis

PET imaging is useful for evaluating locally advanced primary breast cancer. Expression of specific molecular markers in these cancers, such as estrogen receptor (ER), progesterone receptor (PR), and HER2 status, has direct prognostic and therapeutic implications in patient management. This study aimed to determine whether a relationship exists between tumor glucose use and important molecular markers in invasive breast cancer. For our purposes, tumor glucose use is quantified by the PET-derived parameter maximum standardized uptake value (SUV).

METHODS

Breast tumors from 36 patients were excised and examined histologically after PET. ER, PR, and HER2 status were determined for all lesions histopathologically. In addition, genomewide expression for a subset of 20 tumors was analyzed using the human genome U133A oligonucleotide microarray.

RESULTS

A significant association was found between estrogen ER status and lesion SUV. ER-negative tumors (n = 17; median SUV, 8.5) demonstrated a significantly higher maximum SUV than did ER-positive tumors (n = 19; median SUV, 4.0) (P < 0.001). No significant association existed between SUV and PR status, HER2/neu status, lymph node involvement, or tumor size. Unsupervised hierarchic clustering of the 20 genetically profiled cancers segregated tumor samples into 2 primary groups of 10 patients each, largely corresponding to ER status.

CONCLUSION

In locally invasive primary breast cancer, ER-negative tumors display higher (18)F-FDG uptake than ER-positive tumors. Microarray analysis confirms these data and identifies genes associated with increased glucose use as measured by PET. These genes significantly overlap those of a previously validated ER-status molecular phenotype. These preliminary data support a growing body of evidence that ER-positive and ER-negative breast cancers have distinct disease-specific patterns. Further validation prospectively and with larger numbers will be required to establish a robust molecular signature for metabolic uptake and patterns of aggressive behavior in advanced breast cancer.

Incidental breast lesions identified by 18F-fluorodeoxyglucose-positron emission tomography

BACKGROUND

Positron emission tomography (PET) scanning is now part of the standard evaluation for patients with a variety of different malignancies. We describe our experience with breast incidentalomas in a large series of PET scans performed for patients without a known history of breast cancer.

MATERIALS AND METHODS

From March 2000 through June 2007, approximately 45,000 PET scans were performed; 163 had breast findings unrelated to the primary malignancy. In 103 of 163 (63%), findings included physiologic variation, lactation, implants, or benign calcifications. Chart review was conducted in the remaining 60 of 163 patients (37%).

RESULTS

In 20 of 60 patients (33%), no additional evaluation was performed due to advanced stage of the primary malignancy; 40 of 60 (67%) underwent additional imaging and evaluation. In 16 of 40 patients (40%), the lesion resolved on repeat PET; the lesion persisted in 10 of 40 (25%). Additional breast imaging was performed in 14 of 40 (35%). In total, 12 of 40 (30%) underwent biopsy; 7 of 40 (18%) were positive for malignancy.

CONCLUSIONS

In our experience, 29% of breast incidentalomas (7 of 24) with persistent imaging findings were malignant. Further evaluation of these lesions should be based on overall clinical status. In patients where results would not change overall management, biopsy may not be warranted.

Study of quadrant high-dose intraoperative radiation therapy for early-stage breast cancer

BACKGROUND

Partial breast irradiation has been tested in limited pilot studies and shown to provide acceptable cosmesis, minimal toxicity and adequate local control. The aim of this study was to determine the feasibility of using quadrant high-dose intraoperative radiation therapy (IORT) for the treatment of early-stage breast cancer.

METHODS

Fifty-two women with early-stage breast cancer were treated with breast-conserving therapy and IORT between October 2002 and January 2006. The first 18 women received a radiation dose of 20 Gy. The protocol was then amended and the remaining 34 women were treated with 18 Gy. Each patient was evaluated after surgery, and at 3, 6 and 12 months; complications, toxicity and cosmetic outcomes were recorded by the breast surgeon.

RESULTS

Women treated with 18 Gy appeared to have a more favourable cosmetic outcome compared with the earlier treatment group. At last follow-up, none of the women treated on the protocol had a breast recurrence.

CONCLUSION

Experience suggests that this IORT technique is feasible, although further follow-up is necessary to assess its therapeutic value.

The risk of axillary relapse after sentinel lymph node biopsy for breast cancer is comparable with that of axillary lymph node dissection: a follow-up study of 4008 procedures

OBJECTIVE

We sought to identify the rate of axillary recurrence after sentinel lymph node (SLN) biopsy for breast cancer.

SUMMARY BACKGROUND DATA

SLN biopsy is a new standard of care for axillary lymph node staging in breast cancer. Nevertheless, most validated series of SLN biopsy confirm that the SLN is falsely negative in 5-10% of node-positive cases, and few studies report the rate of axillary local recurrence (LR) for that subset of patients staged by SLN biopsy alone.

METHODS

Through December of 2002, 4008 consecutive SLN biopsy procedures were performed at Memorial Sloan-Kettering Cancer Center for unilateral invasive breast cancer. Patients were categorized in 4 groups: SLN-negative with axillary lymph node dissection (ALND; n = 326), SLN-negative without ALND (n = 2340), SLN-positive with ALND (n = 1132), and SLN-positive without ALND (n = 210). Clinical and pathologic characteristics and follow-up data for each of the 4 cohorts were evaluated with emphasis on patterns of axillary LR.

RESULTS

With a median follow-up of 31 months (range, 1-75), axillary LR occurred in 10/4008 (0.25%) patients overall. In 3 cases (0.07%) the axillary LR was the first site of treatment failure, in 4 (0.1%) it was coincident with breast LR, and in 3 (0.07%) it was coincident with distant metastases. Axillary LR was more frequent among the unconventionally treated SLN-positive/no ALND patients than in the other 3 conventionally treated cohorts (1.4% versus 0.18%, P = 0.013).

CONCLUSIONS

Axillary LR after SLN biopsy, with or without ALND, is a rare event, and this low relapse rate supports wider use of SLN biopsy for breast cancer staging. There is a low-risk subset of SLN-positive patients in whom completion ALND may not be required.

Isosulfan blue dye reactions during sentinel lymph node mapping for breast cancer

In the United States, identification of the sentinel lymph node (SLN) requires the use of (99m)Tc-labeled colloid, 1% isosulfan blue dye, or both to trace the lymphatic drainage of a given neoplasm. We report our experience with adverse reactions to isosulfan blue dye during SLN mapping in breast cancer. A chart review of the breast cancer SLN database was performed; it included 2392 sequential patients who underwent SLN biopsy involving isosulfan blue dye at Memorial Sloan-Kettering Cancer Center from September 12, 1996, to August 17, 2000. Thirty-nine of 2392 patients (1.6%) had a documented allergic reaction during the mapping procedure. Most reactions (69%) produced urticaria, blue hives, a generalized rash, or pruritus. The incidence of hypotensive reactions was 0.5%. Although anaphylaxis after the injection of isosulfan blue dye is rare, this article highlights the need to suspect anaphylaxis when hemodynamic instability occurs after the injection of this compound. Our experience indicates that bronchospasm and respiratory compromise are unusual and that most patients do not require emergent intubation and can be managed with short-term pressor support. In addition, our data indicate that patients with a sulfa allergy do not display a cross-sensitivity to isosulfan blue dye.

IMPLICATIONS

We report the largest single-institution review of adverse reactions to injection of isosulfan blue dye during sentinel lymph node mapping in breast cancer. Bronchospasm and respiratory compromise are unusual, and most patients can be treated with short-term pressor support. Patients with a sulfa allergy do not display a cross-sensitivity to isosulfan blue dye.

Genomic mapping by end-characterized random clones: a mathematical analysis

Physical maps can be constructed by "fingerprinting" a large number of random clones and inferring overlap between clones when the fingerprints are sufficiently similar. E. Lander and M. Waterman (Genomics 2: 231-239, 1988) gave a mathematical analysis of such mapping strategies. The analysis is useful for comparing various fingerprinting methods. Recently it has been proposed that ends of clones rather than the entire clone be fingerprinted or characterized. Such fingerprints, which include sequenced clone ends, require a mathematical analysis deeper than that of Lander-Waterman. This paper studies clone islands, which can include uncharacterized regions, and also the islands that are formed entirely from the ends of clones.