Triple Negative Breast Cancers (TNBC) subtype is an aggressive disease with poor clinical outcome. The only treatment available is surgery followed by chemotherapy or radiotherapy. Programmed death-ligand 1 (PD-L1) is a trans-membrane protein expressed on a wide variety of cells including immune cells, epithelial and vascular endothelial cells. Recently, PD-1/PD-L1 pathway signaling was described as an adaptive immune resistance mechanism enacted by the tumor cells to evade the immune response. Its presence on tumor cell membranes, acquired for this reason, through time, is an important prognostic value. However, data available in the literature about PD-L1 immunohistochemical expression in breast cancer are often discordant and not uniform, probably for the use of different antibodies clones and the high molecular heterogeneity of the different tumor types. The absence of target therapies, in particular for TNBC, has shifted the clinical attention mainly on the role of PD-L1 in this subtype of breast cancer. In this study, we evaluated tumor and TIL (tumor infiltrating lymphocytes) PDL-1 expression in a series of TNBC, included in Tissue Micro Arrays (TMAs), to define its real prognostic value, optimizing immunohistochemistry method with an “approved for diagnostic assay” antibody. PD-L1 expression directly correlated with proliferation index (Ki-67), glycemia, the presence of diabetes and indirectly with menopausal status, presence of lymph node metastasis and relapse. The analysis of Kaplan–Meier showed that an increased PD-L1 expression was strongly associated with better disease-free survival (DFS) but not correlated with overall survival (OS). Our data confirmed that PD-L1 could be an important marker for prognostic stratification and for planning immune checkpoint inhibitors therapies in patients with TNBC.

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PURPOSE We compared the endocrine effects of 6 and 12 months of adjuvant letrozole versus tamoxifen in postmenopausal patients with hormone-responsive early breast cancer within an ongoing phase III trial. PATIENTS AND METHODS Patients were randomly assigned to receive tamoxifen, letrozole, or letrozole plus zoledronic acid. Serum values of estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, dehydroepiandrosterone-sulphate (DHEA-S), progesterone, and cortisol were measured at baseline and after 6 and 12 months of treatment. For each hormone, changes from baseline at 6 and 12 months were compared between treatment groups, and differences over time for each group were analyzed. Results Hormonal data were available for 139 postmenopausal patients with a median age of 62 years, with 43 patients assigned to tamoxifen and 96 patients assigned to letrozole alone or combined with zoledronic acid. Baseline values were similar between the two groups for all hormones. Many significant changes were observed between drugs and for each drug over time. Namely, three hormones seemed significantly affected by one drug only: estradiol that decreased and progesterone that increased with letrozole and cortisol that increased with tamoxifen. Both drugs affected FSH (decreasing with tamoxifen and slightly increasing with letrozole), LH (decreasing more with tamoxifen than with letrozole), testosterone (slightly increasing with letrozole but not enough to differ from tamoxifen), and DHEA-S (increasing with both drugs but not differently between them). Zoledronic acid did not have significant impact on hormonal levels. CONCLUSION Adjuvant letrozole and tamoxifen result in significantly distinct endocrine effects. Such differences can explain the higher efficacy of letrozole as compared with tamoxifen.

The aim of the study is to analyse whether letrozole (L) and zoledronic acid plus L (ZL) are more effective than tamoxifen (T) as adjuvant endocrine treatment of premenopausal patients with breast cancer with hormone receptorepositive (HRþ) tumours. Patients and methods: In a phase 3 trial, 1065 premenopausal patients with HR þ early breast cancer received triptorelin to suppress ovarian function and were randomly assigned (1:1:1) to adjuvant T, L or ZL for 5 years. Cancer recurrence, second breast or non-breast cancer and death were considered events for the intention-to-treat disease-free survival (DFS) analysis. Results: With a 64-month median follow-up and 134 reported events, the disease-free rate at 5 years was 85.4%, 93.2% and 93.3% with T, L and ZL, respectively (overall P Z 0.008). The hazard ratio for a DFS event was 0.52 (95% confidence interval [CI], 0.34 to 0.80; P Z 0.003) with ZL vs T, 0.72 (95% CI, 0.48 to 1.07; P Z 0.06) with L vs T and 0.70 (95% CI, 0.44 to 1.12; P Z 0.22) with ZL vs L. With 36 deaths, there was no significant difference in overall survival (P Z 0.14). Treatment was stopped for toxicity or refusal in 7.3%, 7.3% and 16.6% patients, and in the safety population, grade 3e4 side-effects were reported in 4.2%, 6.9% and 9.1% patients treated with T, L or ZL, respectively. Conclusion: HOBOE study shows that in premenopausal patients with early breast cancer undergoing ovarian function suppression with triptorelin, ZL significantly improves DFS, while worsening compliance and toxicity, as compared with T. (NCT00412022)

NCT00331097.