REHA AKPINAR, HALE DEMIR, ŞENNUR İLVAN
Turkish Journal of Oncology - 2024;39(2):153-166
DOI : 10.5505/tjo.2024.4254 OBJECTIVE Breast carcinoma (BC) is the most common cancer in women, and, in particular, some subtypes are established as suitable for immunotherapy strategies targeting immune checkpoints. Programmed cell death-1 (PD-1), as well as cytotoxic T lymphocyte-associated protein-4 (CTLA-4), has an important role in the tumor microenvironment to escape from the immune system. In this study, we examined the relationship of Programmed cell death-1 (PD-L1) expression with survival, recurrence, and other prognostic factors. METHODS This retrospective cohort comprised tissue microarray blocks of 391 cases examined at the same institute between 2000-2012. All cases were completely resected tumors, without neoadjuvant therapy, with more than 5 years of follow-up. Clinical follow-up and all pathologic parameters were recorded. PD-L1 immunohistochemistry (SP263) was applied, then staining details including density, percentage, and patterns were noted for tumor areas and immune cells. PD-L1 expression results were analyzed, and its relationship with prognostic parameters and survival was investigated. RESULTS PD-L1 expression was detected in 90 (24.8%) cases: 55 in only tumor-infiltrating lymphocytes (TILs), 35 in both tumor and TILs. Statistically, there was no significant relationship between PD-L1 expression and survival. However, high histologic grade, high scores in pleomorphism and mitosis, mild stromal reaction, dense immune cell infiltration, perineural invasion, absence of lymph node metastasis, negativity of ER and PR, HER2 expression, and high Ki-67 results had a significant relationship with PD-L1 expression. CONCLUSION Consistent with the literature, our results showed that PD-L1 expression in triple-negative and HER2 overexpressed types and in the presence of TILs is higher than in other breast cancers.
