Expression of Programmed Death Ligand-1 and Correlation with Clinicopathological Features and CD8 Infiltration in Breast Cancer

Abstract

Background: Breast cancer (BC) is considered one of the most diversified types of tumors, characterized by a high mutational burden in  the tumor milieu and a lack of immune cell makeup. The programmed death receptor-1 (PD -1)/programmed death ligand-1 (PD -L1) axis  has been identified as a new target in the field of immunotherapy because, when activated, they worsen the future scenarios of the disease by helping tumor cells (TC) to escape immune surveillance. This study aims to investigate the expression of PD-L1 in BC tissues  from Sudanese ladies and correlate its expression with clinicopathological features and the infiltration of CD8+T lymphocytes by  immunohistochemistry (IHC).

Methods: One hundred and fifty archived BC blocks were collected from National Public Health Laboratory from January 2019 to August  2020. Data regarding age, TNM staging, grade, and hormonal status were considered. Tissue sections were examined using IHC to  determine the expression of PD-L1 and CD8.

Results: Among one hundred and fifty BC samples, 73 (48.7%) were TNBCs, and 77 (51.3%)  were hormone-positive BCs. PD-L1 was significantly associated with BC subtypes, especially TNBCs (P = 0.001), a similar significant  association was shown with CD8 infiltration (P = 0.006). None of the clinicopathological features were associated with PD-L1 expression.

Conclusion: PD-L1 expression is strongly associated with TNBC’s and linked to CD8+ cells infiltration to the tumor milieu. Moreover, no  correlation has been observed between the expression of PD-L1 and clinicopathological features in this study.