Evaluation of Programmed Death Ligand-1 (PD-L1) and B-cell Lymphoma 2 (BCL2) protein expression using immunohistochemistry in colorectal carcinoma patients from Anbar Governorate

Abstract

Colorectal carcinoma is among the most prevalent malignancies worldwide. PD-L1 is an immune-checkpoint ligand that can contribute to tumor immune evasion whereas BCL2 is an anti-apoptotic protein involved in cell-survival pathways, with its mutation frequently observed in various human cancers. This study aimed to evaluate the prognostic significance of immunohistochemically identified PD-L1 and BCL2 proteins in colorectal carcinoma. Sixty paraffin-embedded colorectal carcinoma tissue specimens were subjected to immunohistochemistry (IHC) staining for PD-L1 and BCL2 expression, which was analyzed using the DAKO scoring system (0: 0–4%, 1: 5–24%, 2: 25–49%, 3: 50–74%, 4: 75–100%). PD-L1 protein expression was detected in all patients, with immunoreactivity noted in 33.3% (score 3), 31.7% (score 2), 20.0% (score 4), and 15.0% (score 1), with score 0 cases showing no detectable immunoreactivity Similarly, Bcl-2 protein expression was identified in all colorectal carcinoma patients, with immunoreactivity observed in 38.3% (score 3), 25.0% (score 2), 20.0% (score 4), and 16.7% (score 1), while no detectable immunoreactivity was seen in score 0 cases. These findings highlight the ubiquitous expression of PD-L1 and Bcl-2 in colorectal carcinoma and their potential role as prognostic biomarkers, providing insights into their relevance in cancer progression and therapeutic response.