An Immunoscore Using PD-L1, CD68, and Tumor-infiltrating Lymphocytes (TILs) to Predict Response to Neoadjuvant Chemotherapy in Invasive Breast Cancer.

Response to neoadjuvant chemotherapy (NAC) in invasive breast cancer (IBC) is partly regulated by the immune microenvironment. We evaluated immune checkpoint PD-L1 expression, presence of CD68+ cells of macrophage/monocytic lineage and stromal tumor-infiltrating lymphocytes (TILs) in prechemotherapy biopsies and correlated with NAC response. We studied 76 cases of IBC. Prechemotherapy biopsies with >30% TILs were considered lymphocyte-rich IBC. We performed immunohistochemistry for PD-L1 and CD68. Prechemotherapy cores showing >1% PD-L1+ immune or tumor cells were considered positive. CD68 was positive if >40% of tumor stroma contained CD68+ cells or atleast 50% of tumor cells showed infiltration by CD68+ cells. Residual Cancer burden (RCB) Score of 0/I represented excellent response to NAC and RCB II or III unfavorable response. Thirty-five patients had RCB 0/I and 41 pts RCB II/ III. TILs>30% were present in prechemotherapy biopsies in 19 pts of whom 14 showed RCB 0/I (P=0.0075). Twenty-seven cases were PD-L1+ and 20 had an RCB 0/I (P=0.0003). Twenty-two cases were CD68+ of whom 18 showed RCB 0/I (P=<0.0001) There was a significant association between TILs>30%, PD-L1+ and CD68+ expression. Using atleast one of these immunologic parameters identified 26 of 35 patients with RCB 0/I and showed a higher sensitivity for response prediction than TILs alone (40% vs. 74.3%). In conclusion we demonstrate that high numbers of CD68+ monocytic/macrophage cells and PD-L1 expression in IBC shows significant association with NAC response. An immune biomarker profile including TILs, PD-LI and CD68 is more sensitive for NAC response prediction than TILs alone.

Invasive mucinous carcinoma of the breast and response patterns after neoadjuvant chemotherapy (NAC).

AIMS: Neoadjuvant chemotherapy (NAC) is often used to treat localised invasive breast cancer. Invasive mucinous carcinoma (IMC) is considered to be an indolent form of invasive breast cancer, and is rarely treated with NAC. We report the largest series of IMCs treated with NAC, and report a characteristic, but not well recognised, pattern of pathological response. METHODS AND RESULTS: Our series included seven patients with IMC treated with NAC. Three patients presented with locally advanced disease, three patients had tumours that were HER-2/neu-positive, and four patients had tumours with admixed mucinous and micropapillary features. Clinical and imaging assessment of response showed persistent and, in some cases, progressive disease, despite evidence of significant pathological response in these cases. Pathological assessment after NAC demonstrated marked reduction in tumour cellularity, but persistent space-occupying mucin pools, showing acellular mucin in one case, <1% tumour cellularity in three cases, and 5-10% cellularity in three cases in both the treated breast and axillary lymph nodes. CONCLUSIONS: Persistent mass-forming low-cellular or acellular mucin pools can result in discordant clinical, imaging and pathological findings in IMC treated with NAC.

Pleomorphic Lobular Carcinoma in Situ Diagnosed by Breast Core Biopsy: Clinicopathologic Features and Correlation With Subsequent Excision.

INTRODUCTION: Pleomorphic lobular carcinoma in situ (PLCIS) is a variant of LCIS with high-grade morphologic features. The number of case series studying PLCIS is limited, and clinical management of patients with PLCIS is controversial. We report a breast core biopsy (BCBx) series of PLCIS. MATERIALS AND METHODS: We reviewed 37 cases of PLCIS with or without microinvasion diagnosed by BCBx. PLCIS was defined as dyscohesive cells showing acinar expansion and loss of immunohistochemical membranous expression of e-cadherin or beta-catenin with nuclear pleomorphism with at least 2- to 3-fold variation in nuclear size, membrane irregularities, and variably prominent nucleoli. Clinical information and findings on excision were evaluated. RESULTS: Thirty-one (84%) patients presented with mammographic calcifications, 4 (11%) presented with ultrasound findings, 1 (3%) presented with magnetic resonance imaging enhancement, and 1 (3%) with combined imaging abnormality. The mean patient age was 62.3 years. Nineteen patients (51%) had a family history of breast cancer. Microinvasion was present on BCBx in 9 (24%) of the 37 patients. Excision, available in 34 patients, demonstrated invasive carcinoma in 24 (65%), which was multifocal in 11 (46%). Twenty-three patients with PLCIS without microinvasion on BCBx, and without known history of ipsilateral invasive cancer, underwent excision; 14 of these patients demonstrated invasive carcinoma, representing an upgrade to invasive carcinoma of 60%. CONCLUSION: We report the largest BCBx series of PLCIS and confirm its aggressive biology and frequent association with multifocal invasive lobular carcinoma, as well as frequent presentation in patients with a family history of breast cancer. Our results support excision to negative margins.

Core Biopsy of Vascular Neoplasms of the Breast: Pathologic Features, Imaging, and Clinical Findings.

Vascular lesions (VLs) of the breast present a diagnostic challenge on breast core biopsy (BCBx). We report on 27 VLs presenting on BCBx. The mean patient age was 60 years, and mean size was 7.5 mm (range, 1.6 to 16 mm). Presentation included palpable mass in 6 (22%), incidental in 6 (22%), and an imaging abnormality in 15 (56%) cases. Imaging impression included hematoma (24%), lymph node (10%), fat necrosis (10%), tortuous vessel (5%), and not provided in 52%. The lesions were classified on the basis of BCBx or BCBx and excision (available in 16 pts) as follows: 1 low-grade angiosarcoma, 8 angiolipomas, 6 capillary hemangiomas, 4 cavernous hemangiomas, 2 hemangiomas (not otherwise specified), 1 papillary endothelial hyperplasia, and 5 perilobular hemangiomas. The angiosarcoma was 9 mm, detected incidentally by magnetic resonance imaging, and showed dissection of stromal collagen, infiltration of glands, high cellularity, moderate cytologic atypia, scant mitotic activity, and Ki-67 reactivity of 10%. Among the 26 benign VLs, worrisome histologic features were noted in 14 on BCBx, including anastomosing vascular channels in 9, moderate cytologic atypia in 4, high cellularity in 2, Ki-67>10% in 2, mitotic activity in 1, and infiltration of glands in 1. Of the 12 VLs without worrisome features, the lesion extended to edge of core in 8, precluding complete evaluation. BCBx of VLs presents diagnostic challenges due to overlapping clinicopathologic and radiologic features with low-grade angiosarcoma. If completeness of removal is documented on BCBx, and cytoarchitectural changes are not worrisome, follow-up could be considered rather than excision. However, only 4 of these cases fulfilled those criteria.

Correlation of histopathologic features of ductal carcinoma in situ of the breast with the oncotype DX DCIS score.

The Oncotype DX Breast Cancer Assay for ductal carcinoma in situ is used to determine local recurrence risk in patients with ductal carcinoma in situ. The results help select patients with low-risk ductal carcinoma in situ who could forgo radiation therapy after conservative surgery. The genes assessed include five proliferation genes, progesterone receptor (PR), and GSTM-1. Our objective was to determine if PR, mitotic counting, or any other pathologic feature of ductal carcinoma in situ could predict the Oncotype DX DCIS Score. We identified 46 cases of ductal carcinoma in situ with a Oncotype DX DCIS Score. In addition to information obtained from routine pathology, we counted mitotic figures in the ductal carcinoma in situ and noted presence of dense chronic inflammatory infiltrate surrounding ductal carcinoma in situ. We found that PR ≥ 90% (P = 0.004), mitotic count ≤ 1 (P = 0.045), estrogen receptor ≥ 90% (P = 0.046), and low nuclear grade (P < 0.0001) were associated with a low score. Dense chronic inflammation surrounding ductal carcinoma in situ was associated with a high score (P = 0.034).All 13 cases with PR ≥ 90%, ≤ 1 mitotic figure and absence of dense chronic inflammation around ductal carcinoma in situ had a low score (100% specificity). A low score was not observed in any case with at least two of the following--negative PR, >1 mitotic figure, and/or presence of dense chronic inflammation around ductal carcinoma in situ (100% specificity). Our study suggests using a combination of PR (≥ 90% vs negative) with mitotic count in ductal carcinoma in situ (≤ 1 vs >1) and dense chronic inflammation around ductal carcinoma in situ one could predict the Oncotype DX DCIS score. Mitotic counting and evaluation of immune response might provide prognostic information in ductal carcinoma in situ.

Mitotic counts in breast cancer after neoadjuvant systemic chemotherapy and development of metastatic disease.

Although pathologic complete response after neoadjuvant systemic chemotherapy (NST) is associated with an excellent prognosis, the prognosis for patients with residual disease is variable. The mitotic count (MC) is commonly used in the evaluation of histologic tumor grade, but its prognostic value relative to other factors when determined after NST has not been studied. We evaluated MC in the residual tumor after NST in order to determine whether it provided prognostic information independent of other factors, including the residual cancer burden (RCB). We retrospectively reviewed pathologic specimens from 80 patients with localized breast cancer who received standard NST, of whom 61 had residual disease evaluable for MC analysis and RCB score. The exact number of mitotic figures was counted in 10 high power (40×) fields (hpf). We classified tumors as having high (≥13 per 10 hpf) and low (<13 per 10 hpf) MC because this threshold fell at the midpoint for an intermediate MC score in the Nottingham combined histologic grade. Distant metastases developed in 2 of 32 (6.3 %) patients with a low MC compared with 18 of 29 (62.1 %) with a high MC (log-rank test, p < 0.001). When adjusted for other covariates, including age, estrogen receptor, HER2/neu expressions, and RCB score, a high MC was associated with a significantly higher risk of developing distant metastases (hazard ratio 11.21, 95 % CI [2.19, 57.37]; p = 0.004). Our findings indicated that evaluation of MC after NST warrants validation and further evaluation as a prognostic marker in breast cancer.

Hsa-miR-375 is differentially expressed during breast lobular neoplasia and promotes loss of mammary acinar polarity.

Invasive lobular carcinoma (ILC) of the breast, characterized by loss of E-cadherin expression, accounts for 5-15% of invasive breast cancers and it is believed to arise via a linear histological progression. Genomic studies have identified a clonal relationship between ILC and concurrent lobular carcinoma in situ (LCIS) lesions, suggesting that LCIS may be a precursor lesion. It has been shown that an LCIS diagnosis confers a 15-20% risk of progression to ILC over a lifetime. Currently no molecular test or markers can identify LCIS lesions likely to progress to ILC. Since microRNA (miRNA) expression changes have been detected in a number of other cancer types, we explored whether their dysregulation might be detected during progression from LCIS to ILC. Using the Illumina miRNA profiling platform, designed for simultaneous analysis of 470 mature miRNAs, we analysed the profiles of archived normal breast epithelium, LCIS lesions found alone, LCIS lesions concurrent with ILC, and the concurrent ILCs as a model of linear histological progression towards ILC. We identified two sets of differentially expressed miRNAs, the first set highly expressed in normal epithelium, including hsa-miR-224, -139, -10b, -450, 140, and -365, and the second set up-regulated during lobular neoplasia progression, including hsa-miR-375, -203, -425-5p, -183, -565, and -182. Using quantitative RT-PCR, we validated a trend of increasing expression for hsa-miR-375, hsa-miR-182, and hsa-miR-183 correlating with ILC progression. As we detected increased expression of hsa-miR-375 in LCIS lesions synchronous with ILC, we sought to determine whether hsa-miR-375 might induce phenotypes reminiscent of lobular neoplasia by expressing it in the MCF-10A 3D culture model of mammary acinar morphogenesis. Increased expression of hsa-miR-375 resulted in loss of cellular organization and acquisition of a hyperplastic phenotype. These data suggest that dysregulated miRNA expression contributes to lobular neoplastic progression.