Mixed Neuroendocrine-Non-Neuroendocrine Neoplasms of the Pancreas

Pancreatic mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are rare neoplasms, composed of at least two components. The neuroendocrine part is always present. Histology is the most important tool for the diagnosis, but in the case of MiNEN, it is also important for the use of immunohistochemistry, which should include neuroendocrine but also ductal and acinar markers. Each component should be specifically described in the final pathology report, including the percentage on the entire tumor mass. The prognosis of MiNEN is very heterogeneous and depends on the different tumor components.

New insights in gastrointestinal "pediatric" neoplasms in adult patients: pancreatoblastoma, hepatoblastoma and embryonal sarcoma of the liver. A practical approach by GIPPI-GIPAD Groups

Pediatric solid neoplasms are rare and very different from those observed in adults. The majority of them are referred to as embryonal because they arise as a result of alterations in the processes of organogenesis or normal growth and are characterized by proliferation of primitive cells, reproducing the corresponding tissue at various stages of embryonic development. This review will focus on embryonal gastrointestinal pediatric neoplasms in adult patients, including pancreatoblastoma, hepatoblastoma, and embryonal sarcoma of the liver. Although they are classically considered pediatric neoplasms, they may (rarely) occur in adult patients. Hepatoblastoma represents the most frequent liver neoplasm in the pediatric population, followed by hepatocellular carcinoma and embryonal sarcoma of the liver; while pancreatoblastoma is the most common malignant pancreatic tumor in childhood. Both in children and adults, the mainstay of treatment is complete surgical resection, either up front or following neoadjuvant chemotherapy. Unresectable and/or metastatic neoplasms may be amenable to complete delayed surgery after neoadjuvant chemotherapy. However, these neoplasms display a more aggressive behavior and overall poorer prognosis in adults than in children, probably because they are diagnosed in later stages of diseases.

Molecular Analysis of an Intestinal Neuroendocrine/Non-neuroendocrine Neoplasm (MiNEN) Reveals MLH1 Methylation-driven Microsatellite Instability and a Monoclonal Origin: Diagnostic and Clinical Implications

Mixed neuroendocrine/non-neuroendocrine neoplasms (MiNEN) are rare mixed epithelial neoplasms in which a neuroendocrine component is combined with a non-neuroendocrine component. Here, we provide the clinical, pathologic, and molecular report of a 73-year-old-man presenting with an intestinal MiNEN. The lesion was composed of a well-differentiated G3 neuroendocrine tumor and a colloid adenocarcinoma. The molecular characterization was performed using a multigene next-generation sequencing panel. The neoplasm displayed microsatellite instability due to MLH1 promoter methylation. The extended molecular profile documented the same mutations affecting ARID1A, ASXL1, BLM, and RNF43 genes in both components, indicating a monoclonal origin of the tumor. Regarding component-specific gene mutations, BRCA2 was specifically altered in the neuroendocrine area. It may represent a new actionable target for precision oncology in MiNEN, but the lack of its alteration in the colloid component calls for further considerations on intratumor heterogeneity. The most important finding with potential immediate implications regards the presence of microsatellite instability: it indicates that this molecular alteration should become part of the diagnostic algorithm for these rare neoplasms.

Ki67/MART1 and p63/SOX10 Dual Immunohistochemistry Allows a Correct Interpretation of the Melanocytic Component in the Diagnosis of Pigmented Pilomatricoma

Pilomatricoma is a relatively common benign cutaneous adnexal tumor and a well-recognized entity, while its pigmented variant is far less common and less reported. Its estimated frequency ranges from 11 to 24%, according to a limited number of published case series. This article describes the case of a 42-year-old man presenting a firm subcutaneous nodule of the periareolar region. Histopathologic examination revealed a cystic lesion composed of matrical and supramatrical cells accompanied by a foreign body granulomatous cell reaction. Interestingly, a hyperpigmented area with numerous hyperplastic melanocytes and few mitoses was detectable. In order to assess the cell lineage of the mitotically active component in the hyperpigmented area, double immunohistochemistry with Ki67/Mart1 and p63/SOX10 was performed. Pigmented pilomatricoma is an underrecognized, underreported variant, and double immunohistochemistry stain is an effective tool in providing the correct interpretation of the proliferative activity in the different cellular populations.

Prognostic factors in phyllodes tumours of the breast: retrospective study on 166 consecutive cases

BACKGROUND

Phyllodes tumours (PTs) are rare fibroepithelial tumours accounting for <1% of all breast tumours. We assessed clinicopathological features and their prognostic effect in a single-institution patients' cohort.

METHODS

Patients diagnosed with PT between 2001 and 2018 at our institution were identified. Clinical, surgical and pathological features were collected. Phyllodes-related relapse was defined as locoregional or distant recurrence (contralateral excluded), whichever first.

RESULTS

A total of 166 patients were included: 115 with benign, 30 with borderline and 21 with malignant PTs. Features associated with malignant PT were younger age, larger T size, higher mitotic count, marked cytological atypia, stromal overgrowth, stromal hypercellularity, necrosis and heterologous differentiation (all p<0.01). The majority of patients with malignant PT underwent mastectomy (63.2% vs 3% of benign/borderline, p<0.001) and had negative surgical margins (83.3%). 4-year cumulative phyllodes-related relapse incidence was 7% for benign/borderline PT and 21.3% for malignant PT (p=0.107). In the entire cohort, marked cellular atypia and heterologous differentiation were associated with worse phyllodes-related relapse-free survival (HR 14.10, p=0.036 for marked vs mild atypia; HR 4.21, p=0.031 for heterologous differentiation present vs absent). For patients with benign PT, larger tumour size was associated with worse phyllodes-related relapse-free survival (HR 9.67, p=0.013 for T>5 cm vs T≤2 cm). Higher tumour-infiltrating lymphocytes (TILs) were associated with borderline and malignant PT (p=0.023); TILs were not associated with phyllodes-related relapse-free survival (HR 0.58, p=0.361 for TILs>2% vs≤2%). Overall, four patients died because of PT: three patients with malignant and one with borderline PT.

CONCLUSIONS

Patients with malignant PT had increased rates of phyllodes-related relapse and phyllodes-related death. Cellular atypia and heterologous differentiation were poor prognostic factors in the entire cohort; large tumour size was associated with an increased risk of phyllodes-related relapse in benign PT.

Impact of estrogen receptor levels on outcome in non-metastatic triple negative breast cancer patients treated with neoadjuvant/adjuvant chemotherapy

Although 1% is the recommended cut-off to define estrogen receptor (ER) positivity, a 10% cut-off is often used in clinical practice for therapeutic purposes. We here evaluate clinical outcomes according to ER levels in a monoinstitutional cohort of non-metastatic triple-negative breast cancer (BC) patients undergoing (neo)adjuvant chemotherapy. Clinicopathological data of 406 patients with ER < 10% HER2-negative BC treated with (neo)adjuvant chemotherapy between 01/2000 and 04/2019 were collected. Patients were categorized in ER-negative (ER < 1%; N = 364) and ER-low positive (1-9%, N = 42). At a median follow-up of 54 months, 88 patients had relapsed and 64 died. No significant difference was observed in invasive relapse-free survival (iRFS) and overall survival (OS) according to ER expression levels, both at univariate and multivariate analysis (5-years iRFS 74.0% versus 73.1% for ER-negative and ER-low positive BC, respectively, p = 0.6; 5-years OS 82.3% versus 76.7% for ER-negative and ER-low positive BC, respectively, p = 0.8). Among the 165 patients that received neoadjuvant chemotherapy, pathological complete response rate was similar in the two cohorts (38% in ER-negative, 44% in ER-low positive, p = 0.498). In conclusion, primary BC with ER1-9% shows similar clinical behavior to ER 1% BC. Our results suggest the use of a 10% cut-off, rather than <1%, to define triple-negative BC.

Validation of Residual Proliferative Cancer Burden as a Predictor of Long-Term Outcome Following Neoadjuvant Chemotherapy in Patients with Hormone Receptor-Positive/Human Epidermal Growth Receptor 2-Negative Breast Cancer

Background

The integration of residual cancer burden (RCB) and post‐treatment Ki67 as residual proliferative cancer burden (RPCB) has been proposed as a stronger predictor of long‐term outcome in unselected patients with breast cancer (BC) undergoing neoadjuvant chemotherapy (NACT), as compared with RCB. However, no specific analysis in hormone‐receptor‐positive (HR+) human epidermal growth receptor 2‐negative (HER2−) BC is available so far.

Materials and Methods

A cohort of 130 patients with HR+/HER2− BC who underwent NACT between 2000 and 2014 was included. Archival surgical specimens were evaluated for RCB. RPCB was calculated by combining RCB and Ki67 as previously described. Patients were categorized in four RCB and RPCB categories (pathological complete response and tertiles). Disease‐free survival (DFS) and overall survival (OS) estimates were determined by Kaplan‐Meier analysis and compared using the log‐rank test. Overall change of χ² and c‐indexes were used to compare the performance of the prognostic models.

Results

RPCB was calculated for 85 patients. After a median follow up of 8.5 years, RCB was associated with OS (p = .048) but not with DFS (p = .152); RPCB was instead significantly associated with both DFS and OS (p = .034 and p < .001, respectively). In terms of OS, RPCB provided a significant amount of prognostic information beyond RCB (∆χ² 5.73, p < .001). In addition, c‐index for OS prediction was significantly higher for RPCB as compared with RCB (0.79 vs. 0.61, p = .03).

Conclusion

This is the first study evaluating RPCB in patients with HR+/HER2− BC treated with NACT. In this independent cohort, RPCB was a strong predictor of DFS and OS. The better performance of RPCB versus RCB was in part due to the ability of RPCB to discriminate a subgroup of patients with a particularly worse prognosis after NACT, who may be candidates for clinical trials evaluating novel adjuvant strategies.

Implications for Practice

The present work validated residual proliferative cancer burden (RPCB) as a strong predictor of long‐term outcome in patients with hormone receptor‐positive human epidermal growth receptor 2‐negative (HR+/HER2−) breast cancer (BC) treated with neoadjuvant chemotherapy. In addition, results from the present study suggest RPCB as a promising tool to identify patients with HR+/HER2− BC who might potentially benefit from the inclusion in clinical trials evaluating novel or escalated postneoadjuvant treatment strategies because it allowed to discriminate a subgroup of patients with particularly poor prognosis despite having received subsequent endocrine therapy in the adjuvant setting.

This article reports on the prognostic value of the Residual Proliferative Cancer Burden index in a cohort of patients with HR‐positive HER2‐negative breast cancer undergoing neoadjuvant chemotherapy.

ERBB2 mRNA Expression and Response to Ado-Trastuzumab Emtansine (T-DM1) in HER2-Positive Breast Cancer

Trastuzumab emtansine (T-DM1) is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-positive (HER2+) metastatic breast cancer (BC) and for residual disease after neoadjuvant therapy; however, not all patients benefit. Here, we hypothesized that the heterogeneity in the response seen in patients is partly explained by the levels of human epidermal growth factor receptor 2 gene (ERBB2) mRNA. We analyzed ERBB2 expression using a clinically applicable assay in formalin-fixed paraffin-embedded (FFPE) tumors (primary or metastatic) from a retrospective series of 77 patients with advanced HER2+ BC treated with T-DM1. The association of ERBB2 levels and response was further validated in 161 baseline tumors from the West German Study (WGS) Group ADAPT phase II trial exploring neoadjuvant T-DM1 and 9 in vitro BC cell lines. Finally, ERBB2 expression was explored in 392 BCs from an in-house dataset, 368 primary BCs from The Cancer Genome Atlas (TCGA) dataset and 10,071 tumors representing 33 cancer types from the PanCancer TCGA dataset. High ERBB2 mRNA was found associated with better response and progression-free survival in the metastatic setting and higher rates of pathological complete response in the neoadjuvant setting. ERBB2 expression also correlated with in vitro response to T-DM1. Finally, our assay identified 0.20-8.41% of tumors across 15 cancer types as ERBB2-high, including gastric and esophagus adenocarcinomas, urothelial carcinoma, cervical squamous carcinoma and pancreatic cancer. In particular, we identified high ERBB2 mRNA in a patient with HER2+ advanced gastric cancer who achieved a long-lasting partial response to T-DM1. Our study demonstrates that the heterogeneity in response to T-DM1 is partly explained by ERBB2 levels and provides a clinically applicable assay to be tested in future clinical trials of breast cancer and other cancer types.

Integration of tumour infiltrating lymphocytes, programmed cell-death ligand-1, CD8 and FOXP3 in prognostic models for triple-negative breast cancer: Analysis of 244 stage I-III patients treated with standard therapy

BACKGROUND

Tumour infiltrating lymphocytes (TILs) are an established prognostic biomarker for triple-negative breast cancer (TNBC). We evaluated the role of programmed cell-death ligand-1 (PD-L1), CD8 and FOXP3 expression in refining a prognostic model for non-metastatic TNBC beyond classic factors and TILs.

METHODS

Primary tumour samples from 244 early patients with TNBC, all treated with surgery and chemotherapy, were collected. Stromal TILs were evaluated on haematoxylin-eosin slides according to guidelines. PD-L1, CD8 and FOXP3 were assessed by immunohistochemistry and evaluated by digital pathology.

RESULTS

TILs, PD-L1, CD8 and FOXP3 were positively correlated with each other (P < 0.001). TILs were confirmed as an independent prognostic factor. When PD-L1, CD8 and FOXP3 were added to multivariable models including classic factors (age, stage, histologic grade) and TILs, PD-L1 provided the largest amount of additional prognostic information: likelihood ratio χ² 4.60, P = 0.032 (in a model including classic factors and TILs 10% increments) and likelihood ratio χ² 6.50, P = 0.011 (in a model including classic factors and TILs >30% versus <30%). In the subset of patients treated with neoadjuvant chemotherapy, FOXP3 provided further prognostic information beyond classic factors, TILs and pathological complete response (pCR) (likelihood ratio χ² 5.01, P = 0.025). For patients who did not achieve a pCR, the expression of CD8 and PD-L1 was significantly increased from baseline to residual disease.

CONCLUSIONS

Beyond clinicopathological factors and TILs, other immune biomarkers may add prognostic information for early TNBC. The increased PD-L1 expression on residual disease after neoadjuvant chemotherapy strengthens the rationale of testing immune checkpoint inhibitors in the post-neoadjuvant setting.

Abstract P3-08-05: Impact of estrogen receptor levels on outcome in triple negative breast cancer patients treated with (neo)adjuvant chemotherapy

Background: Although 1% is recommended by guidelines as cut-off for estrogen receptor (ER) positivity, the 10% cut-off is often used in clinical practice based on studies showing that breast cancers with ER ≥1% &&lt;10% have biological characteristics and prognosis similar to those with ER &lt;1%. Our aim was to compare disease-free survival (DFS) and overall survival (OS) according to ER level in a cohort of patients with HER2-negative, ER&lt;10% and progesterone receptor &lt;10% undergoing (neo)adjuvant chemotherapy. Methods: Clinicopathological data of patients with triple negative breast cancer (defined as ER and progesterone receptor &lt;10% and HER2-negative) treated at our Institution with (neo)adjuvant chemotherapy between January 2000 and April 2019 were collected. Patients were categorized according to ER expression; &lt;1% or ≥1%&&lt;10%. Pathologic complete response (pCR) was defined as ypT0/is and ypN0. DFS was calculated from date of diagnosis to date of relapse (locoregional or distant), death or last follow up. OS was calculated from the date of diagnosis to date of death or last follow up. Hazard ratios and 95% CI were calculated with the Cox proportional hazard regression model. Results: 406 patients were included: 364 with ER&lt;1%, 42 with ER≥1%&&lt;10%. Main characteristics: median age 54 years (range 25-84), ductal histology 91% (N 367), grade 3 88% (N 350), median ki67 58%, stage at diagnosis: I 33% (N 134), II 52% (N 212), III 15% (N 59). There was no significant difference in clinicopathological characteristics according to ER level. However, ER≥1%&&lt;10% tumors had a numerically higher frequency of advanced disease stages (I 19% N=8, II 57% N=24, III 24% N=10, p=0.057).Almost half of the patients (41%, N=165) received neoadjuvant chemotherapy: 39% in the ER&lt;1% and 57% in the ER≥1%&&lt;10% cohort (p=0.032). pCR was achieved by 63 patients (38%). pCR rate was similar in the two cohorts (38% in ER&lt;1% cohort, 44% in ER≥1%&&lt;10% cohort, p=0.498). 274 patients (67%) received adjuvant chemotherapy (41 after previous neoadjuvant treatment): 69% in the ER&lt;1% and 55% in the ER≥1%&&lt;10% cohort (p=0.092). With a median follow up of 54 months, 88 patients had relapsed and 64 died. No difference in DFS and OS was observed according to ER levels: 5-year DFS was 73.7% in ER&lt;1% and 73.1% in ER≥1%&&lt;10% cohort (log-rank p=0.610); 5-year OS was 82.3% in ER&lt;1% and 76.7% in ER≥1%&&lt;10% cohort (log-rank p=0.820). Disease stage at diagnosis was the only clinicopathological variable significantly associated with DFS and OS in the overall study cohort (data not shown). DFS and OS Hazard Ratios for ER≥1%&&lt;10% tumors as compared to ER&lt;1% tumors at univariable analysis and after correction by stage are presented in the table. Conclusions: Early HER2-negative primary breast cancer with ER &lt;10% behaves clinically like ER&lt;1% breast cancer in terms of DFS and OS after (neo)adjuvant chemotherapy. Our results support the definition of TNBC as HER2-negative breast cancer with ER&lt;10% and PgR&lt;10%, rather than &lt;1%.

DFS and OS Hazard Ratios for ER≥1%&&lt;10% tumors as compared to ER&lt;1% tumorsDFSHazard Ratio (95% CI)Hazard Ratio (95% CI) corrected by stagep-valueER&lt;1%RefRef0.957ER≥1%&&lt;10%1.19 (0.61-2.30)0.98 (0.51-1.91)OSHazard Ratio (95% CI)Hazard Ratio (95% CI) corrected by stagep-valueER&lt;1%RefRef0.805ER≥1%&&lt;10%1.10 (0.50-2.40)0.90 (0.41-2.00)

Citation Format: Gaia Griguolo, Maria Vittoria Dieci, Michele Bottosso, Vassilena Tsvetkova, Carlo Alberto Giorgi, Silvia Angelini, Giulia Tasca, Enrico Cumerlato, Marcello Lo Mele, PierFranco Conte, Valentina Guarneri. Impact of estrogen receptor levels on outcome in triple negative breast cancer patients treated with (neo)adjuvant 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 P3-08-05.

Abstract P5-06-14: Integrating CD8, FOXP3 and PD-L1 expression in prognostic models for triple negative breast cancer (TNBC): An analysis of 265 patients treated with standard therapy for stage I-III disease

Background: Tumor infiltrating lymphocytes (TILs) are strong prognostic biomarkers for early TNBC. We evaluated the role of CD8, FOXP3 and PD-L1 expression in refining prognostic models for non-metastatic TNBC in a large cohort of patients treated with standard therapy. Methods: Consecutive patients diagnosed with stage I-III TNBC (ER/PgR &lt;10%, HER2 0/1+ or ISH non amplified) between May 2012 and December 2015 were included. All patients received treatment with surgery, chemotherapy (neoadjuvant or adjuvant) and radiotherapy (when indicated). For each case, three FFPE tumor slides were stained for CD8 (Clone C8/144B, Dako Cytomation), FOXP3 (Clone 236A/E7, dilution 1:200, Abcam) and PD-L1 (IHC 73-10 Research Use Only assay developed by Agilent Technologies). One slide was stained for cytokeratins with MNF116. Digital slides were evaluated by a Visiopharm® software application, following alignment of the CD8, FOXP3 and PD-L1 slides with the MNF116 slide. The density of CD8 and FOXP3 expression was calculated as the number of cells/mm2 of stroma area. For PD-L1, the % of positive stromal cells over the total of stromal cells was analyzed. Disease-free survival (DFS) was calculated from diagnosis to relapse or death. The Harrell’s c-index was used to determine the cut-offs for CD8, FOXP3 and PD-L1 to be used in survival analyses. Results: 265 TNBC pts were evaluated. Median TILs was 10% (Q1-Q3 3%-25%), median CD8 was 249 (Q1-Q3 109-568), median FOXP3 was 57 (Q1-Q3 21-134), median PD-L1 was 5.2% (Q1-Q3 0.2%-25.4%). TILs, CD8, FOXP3 and PD-L1 were positively correlated with each other (p&lt;0.001): CD8 showed strong correlation with TILs (Spearman’s coefficient 0.753), FOXP3 and PD-L1 showed moderate correlation with TILs (Spearman’s coefficient 0.535 and 0.587). Higher TILs, CD8, FOXP3 and PD-L1 were associated with age ≤50yrs (p=0.002, p=0.004, p=0.065, p=0.011), Grade 3 (p=0.001, p=0.006, p=0.006, p=0.003) and Ki67 ≥30% (p=0.056, p=0.024, p=0.004, p=0.005). There was no association between immune markers and stage. Among classic clinicopathologic factors, TILs (10% increments) and stage at diagnosis were independent prognostic parameters in multivariate analysis (HR 0.81, 95% CI 0.69-0.94 p=0.005 for TILs, HR 2.01 95% ci 1.01-4.23 P=0.047 for stage II vs stage I and HR 5.31 95% CI 2.54-11.11 p&lt;0.001 for stage III vs stage I). In univariate analysis, high CD8 (≥443), high FOXP3 (≥57) and high PD-L1 (&gt;20%) were all significantly associated with improved DFS (HR 0.36 95%CI 0.18-0.72, p=0.004 for CD8; HR 0.48 95%CI 0.28-0.80, p=0.005 for FOXP3; HR 0.52 95%CI 0.28-0.97, p=0.039 for PD-L1). FOXP3 and PD-L1 provided significant additional prognostic information beyond a model containing TILs and stage: likelihood ratio χ2 5.12, p=0.024 for FOXP3; likelihood ratio χ2 5.52, p=0.019 for PD-L1. CD8 did not add relevant prognostic information beyond TILs and stage (likelihood ratio χ2 2.76, p=0.097). Including both FOXP3 and PD-L1 did not add further prognostic information to models already containing TILs, stage and either FOXP3 or PD-L1. Conclusions: FOXP3 and PD-L1 expression evaluated with a software-assisted method were prognostic for stage I-III TNBC pts treated with standard therapy and may contribute to refine the prognostic stratification beyond stage and TILs.

This study was supported by a grant from Merck KGaA.

Citation Format: Maria Vittoria Dieci, Vassilena Tsvetkova, Gaia Griguolo, Federica Miglietta, Deborah Bacchin, Giulia Tasca, Carlo Alberto Giorgi, Enrico Cumerlato, Enrico Orvieto, Valentina Guarneri, Pierfranco Conte. Integrating CD8, FOXP3 and PD-L1 expression in prognostic models for triple negative breast cancer (TNBC): An analysis of 265 patients treated with standard therapy for stage I-III disease [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 P5-06-14.

Androgen Receptor Expression and Association With Distant Disease-Free Survival in Triple Negative Breast Cancer: Analysis of 263 Patients Treated With Standard Therapy for Stage I-III Disease

Background: We evaluated immunohistochemical AR expression and correlation with prognosis in a large series of homogeneously treated patients with primary TNBC.

Material and Methods: Patients diagnosed with stage I-III TNBC between 2000 and 2015 at Istituto Oncologico Veneto who received treatment with surgery and neoadjuvant and/or adjuvant chemotherapy were included. Whole tissue slides were stained for AR. AR-positive expression was defined as >1% of positively stained tumor cells. Distant-disease-free survival (DDFS) was calculated from diagnosis to distant relapse or death. Late-DDFS was calculated from the landmark of 3 years after diagnosis until distant relapse or death.

Results: We included 263 primary TNBC patients. Mean AR expression was 14% (range 0–100%), and 29.7% (n = 78) of patients were AR+. AR+ vs. AR- cases presented more frequently older age (p < 0.001), non-ductal histology (p < 0.001), G1-G2 (p = 0.003), lower Ki67 (p < 0.001) and lower TILs (p = 0.008). At a median follow up of 81 months, 23.6% of patients experienced a DDFS event: 33.3% of AR+ and 19.5% of AR- patients (p = 0.015). 5 years DDFS rates were 67.2% and 80.6% for AR+ and AR- patients (HR = 1.82 95%CI 1.10–3.02, p = 0.020). AR maintained an independent prognostic role beyond stage, but when TILs were added to the model only stage and TILs were independent prognostic factors. AR was the only factor significantly associated with late-DDFS: 16.4% of AR+ and 3.4% of AR- patients experienced a DDFS after the landmark of 3 years after diagnosis (p = 0.001). Late-DDFS rates at 5 years from the 3-year landmark were 75.8% for AR+ and 95.2% for AR- patients (log-rank p < 0.001; HR = 5.67, 95%CI 1.90–16.94, p = 0.002).

Conclusions: AR expression is associated with worse outcome for patients with TNBC. In particular, AR+ TNBC patients are at increased risk of late DDFS events. These results reinforce the rationale of AR targeting in AR+ TNBC.

Abstract P4-08-04: PD-L1 expression and prognosis in triple negative breast cancer (TNBC): An analysis of 265 patients (pts) treated with standard therapy for stage I-III disease

Background: Targeting the PD-L1/PD-1 axis has proved to be effective in various cancers, including promising data for metastatic TNBC pts. The evaluation of PD-L1 expression is limited by the lack of standardized methods. Here we sought to evaluate the prognostic role of PD-L1 expression in a large cohort of patients with non-metastatic TNBC treated with standard therapy.

Methods:

Consecutive patients diagnosed with stage I-III TNBC (ER and PgR &lt;10%, HER2 0/1+ or ISH non amplified) between May 2012 and December 2015 and treated at the Istituto Oncologico Veneto of Padova were included. All patients received treatment with surgery, chemotherapy (neoadjuvant or adjuvant) and radiotherapy (when indicated).

For each case, one FFPE tumor slide was stained for PD-L1 with the PD-L1 IHC 73-10 Research Use Only assay developed by Agilent Technologies and one slide was stained for cytokeratins with MNF116 (to distinguish MNF116+ tumor cells from MNF116- stromal cells). Digital slides were evaluated by a specifically-developed Visiopharm® software application. Following alignment of the PD-L1 and MNF116 digital slides, the software analyzed PD-L1 expression on tumor cells (% of positively stained tumor cells/total tumor cells) and stromal cells (% of positively stained stromal cells/total stromal cells). Disease-free survival (DFS) was calculated from diagnosis to relapse or death. In survival analyses, PD-L1 was evaluated as continuous and categorical variable.

Results:

265 TNBC pts were evaluated. Median PD-L1 was 2.6% (Q1-Q3 0%-18.6%) on tumor cells and 5.2% (Q1-Q3 0.2%-25.4%) on stromal cells. PD-L1 levels on tumor and stromal cells were positively correlated (spearman's 0.938, p&lt;0.001). For further analyses, PD-L1 on stromal cells was considered. Higher PD-L1 was associated with age &lt;50 yrs (p=0.011), Grade 3 (p=0.003) and Ki67 &gt;30% (p=0.005). Lower PD-L1 was observed in lobular and apocrine tumors (p=0.001).Cox model for DFS showed HR=0.99 (95%CI 0.97-1.00, p=0.059) for every 1% PD-L1 increment.

3-yrs DFS was 86% for pts with PD-L1&gt;20% (n=88, 29%) vs 75% for pts with PD-L1&lt;20% (n=177, 71%): HR 0.52, 95%CI 0.28-0.97, p=0.039. PD-L1 at 20% cut-off maintained prognostic value in multivariate model including stage (HR 0.48, 95%CI 0.25-0.89, p=0.021).

Of the 265 pts included, 108 received neoadjuvant chemotherapy (NACT). Of the 78 pts with residual disease after NACT, 61 had pre- and post-NACT samples evaluable for PD-L1. PD-L1 increased from pre- to post-NACT: median 2.7% (Q1-Q3 0%-26.9%) vs 20.1% (Q1-Q3 5.9%-41.4%), p&lt;0.001. Pts with PD-L1&gt;20% post-NACT showed improved DFS: 3-yrs DFS 68% vs 43% (HR 0.44, 95%CI 0.20-0.96, p=0.039), whereas PD-L1 pre-NACT did not show significant association with DFS in this subgroup (HR 0.47, 95%CI 0.23-1.40, p=0.218).

Conclusions:

PD-L1 expression evaluated with a software-assisted method was prognostic for stage I-III TNBC pts treated with standard therapy. The significant increase of PD-L1 on residual disease post-NACT supports the rationale to evaluate the efficacy of anti-PD-L1 drugs in this high-risk population.

Citation Format: Dieci MV, Orvieto E, Tsvetkova V, Griguolo G, Miglietta F, Bonaguro S, Tasca G, Giorgi CA, Cumerlato E, Guarneri V, Conte P. PD-L1 expression and prognosis in triple negative breast cancer (TNBC): An analysis of 265 patients (pts) treated with standard therapy for stage I-III disease [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 P4-08-04.

Exceptional and Durable Responses to TDM-1 After Trastuzumab Failure for Breast Cancer Skin Metastases: Potential Implications of an Immunological Sanctuary

Breast Cancer (BC) skin metastases represent a challenging clinical scenario. Although they usually arise when other distant metastases are already present, they may also represent a form of locoregional recurrence (LRR). Systemic therapy in this setting may have a role both in case a radical locoregional approach is unfeasible in order to achieve disease control, and as adjuvant strategy after radical removal of cutaneous lesions, in order to prevent or delay subsequent disease spread. Systemic therapy for HER2+ metastatic BC (MBC) currently relies on anti-HER2 targeted agents. In this context TDM1 is an option in trastuzumab-resistant patients.Here we present 2 cases of isolated skin metastases in patients with HER2+ BC progressing during or early after trastuzumab-based therapy, showing impressive responses to TDM1. We hypothesize that the unique properties of skin immune microenvironment may explain the failure of trastuzumab, which exerts its action also through immunological mechanisms, and the subsequent outlier responses to TDM1, that relies on a partially different mechanism of action.

An anti-digoxin monoclonal antibody seems to express more than one functional paratope

An anti-digoxin monoclonal antibody (mAb 4G3) has been produced and characterized with respect to its fine specificity and affinity. In an independent series of experiments anti-idiotypic monoclonal antibody (mAb 7G9) was selected which reacted with the antigen-binding center of an anti-human chorionic gonadotropin monoclonal antibody (anti-hCG mAb 1B10). In detailed studies on its binding characteristics it has been shown that mAb 4G3 binds to an anti-idiotypic monoclonal antibody mAb 7G9 in solution. Western blotting experiments showed that mAb 4G3 reacted against antiidiotypic antibody under non-reducing conditions, only. Moreover, mAb 4G3 has been shown to express self-binding properties. Absorption with saturating amounts of its specific hapten, i.e. digoxin, did not change the binding of mAb 4G3 to anti-idiotypic antibody and its self-binding ability. It is speculated on the basis of these data that mAb 4G3 possesses more than one functional paratope.

Daily fluctuations in the plasma cortisol level of children with rheumatoid arthritis before and after treatment with tetracosactrin ('Cortrosyn Depot') and corticosteroid hormones

Daily fluctuations in plasma cortisol levels were studied in three groups of children with rheumatoid arthritis. One group was untreated with hormones, the second treated with a depot preparation of tetracosactrin, and the third group with corticosteroid hormones. The results obtained were compared with the rhythm in normal children. The daily plasma cortisol fluctuations in children with rheumatoid arthritis who did not receive hormonal treatment differed from those of normal children by the presence of two distinct and characteristic cortisol levels: a peak between 8 a.m. and 12 noon and a minimal level between 4 p.m. and midnight (with a gradual rise after 4 p.m.). The curve of the daily cortisol rhythm in children with rheumatoid arthritis after tetracosactrin treatment was characteristic of the curve in normal children. Steroidtreated children with rheumatoid arthritis had virtually unchanged plasma cortisol concentrations throughout the day.

Adrenocortical function after stimulation with synthetic ACTH

In order to assess the effect of ACTH on the adrenal cortex when used as a therapeutic or diagnostic agent, adrenocortical function was tested before and 2 hours after 0.5 mg tetracosactrin given intramuscularly in 31 healthy children, divided into 4 groups according to age and sex. Mean plasma cortisol levels were shown to be 184% higher than baseline values after administration of the drug, and there were no significant differences related to age or sex. It is suggested that this simple test can be of practical value in the diagnosis of adrenocortical function in young people.