CLINICOPATHOLOGICAL CHARACTERISTICS OF INVASIVE BREAST CARCINOMA ON PDL-1 IMMUNOHISTOCHEMICAL EXPRESSION IN H. ADAM MALIK HOSPITAL MEDAN

Abstract Background: Immune biologic markers that can predict clinical response to anti-PD-1/PD-L1 therapy are needed to identify and validate tumor immunotherapy studies. High PD-L1 expression is associated with increased clinical response in patients with various types of cancer treated with inhibitors of the PD-1/PD-L1 pathway. The researcher wanted to see the clinicopathological characteristics of invasive breast carcinoma according to the immunohistochemical expression of PD-L1. Methods: This study is a descriptive study with a cross-sectional, retrospective approach by looking at secondary data from the medical records of the Department of Surgery, Oncology Division, Haji Adam Malik Hospital from January 1, 2019, to December 31, 2021. Results: Immunohistochemical expression of PD-L1 was positive in 76.6% of invasive breast carcinomas and negative in 23.3% of invasive breast carcinomas. Immunohistochemical expression of PD-L1 was positive in non-specific IBCs that predominated in every molecular subgroup of breast carcinoma. Discussion: Tumours can show positive or negative PD-L1 expression through several biological processes with different functional significance, namely the genetic mechanism of constitutive or oncogene-induced PD-L1 expression, PD-L1 expression induced in T cells, and absence of PD-L1 expression. Due to the absence of T cells and genetic events that block the expression of PD-L1 despite T cell infiltration.