The relations of pdl-1 immünexpression and egfr amplification with clinicopathological features in triple-negatif breast carcinoma

The relations of PDL-1 immünexpression and EGFR amplification with clinicopathological features in triple-negatif breast carcinoma Breast cancer is the most common cancer among women and the most common cause of cancer-related deaths. triple negative breast cancer (TNMK); estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2) negative; It is a group of breast cancers with a higher grade, aggressiveness, low survival and tendency to be seen at a younger age compared to other breast cancers, as well as very limited treatment options. The limited treatment options attract our attention as the molecular pathways that cause the formation and progression of the disease or the escape mechanism of tumor cells (TC) from immune cells (IC) in this disease. Targeted therapies and immune checkpoint inhibitors are a source of hope in the treatment of this disease. Our study included 60 patients who were diagnosed with breast carcinoma in Pamukkale University Faculty of Medicine, Department of Pathology between 2011 and 2023 and were found to be negative for ER, PR, and HER2 in immunohistochemical (IHC) examination, who underwent modified radical mastectomy, breast-conserving surgery, and trucut biopsy. PDL-1 and EGFR results were compared with prognostic parameters and their effects on survival were investigated. The status of tumor-infiltrating lymphocytes (TIL), PDL1 immunoexpression status, EGFR amplification status, and their relationship with each other and other clinicopathological features were investigated. According to the results; PDL-1 staining was positive in 76.7% (46 cases) of the patients. There were 37 cases (61.7%) with a TIL percentage of 20% or more. The rate of PDL-1 positivity is higher in cases with a TIL percentage of 20% or more (p=0.023). Lower PDL-1 (p=0.006) and TIL (p=0.003) were found in Trucut biopsies compared to mastectomy and excision materials. The rate of PDL-1 positivity was found to be lower in invasive tumors associated with DCIS (p=0.047). No difference was found between PDL-1 and TIL rates and survival. EGFR amplification was detected in 51.7% of the patients (31 cases). EGFR amplification was found to be higher in those with a TIL percentage of ≥20% (p=0.039). There was no difference between PDL-1 and EGFR amplification. The survival time of patients with invasive lobular carcinoma (ILC) was found to be shorter than invasive ductal carcinoma (IDC), not otherwise classified (NOS) and metaplastic carcinoma. The results obtained are consistent with the literature, and we predict that PDL-1 immunoexpression and EGFR amplification are seen at high rates in TNBC, and thus our study will be a light source for treatment studies in an aggressive disease such as TNBC with limited treatment options. Keywords: triple negative, breast carcinoma, TIL, PDL-1, EGFR