Zeynep, OFunda, CEvrim, YDeniz, ABülent, YFatih, YN.2023-08-102023-08-102023-03Zeynep O, Funda C, Evrim Y, Deniz A, Bülent Y, Fatih YN.. PD-L1 and PD-L2 expression in colorectal cancer. Indian Journal of Pathology & Microbiology. 2023 Mar; 66(1): 31-370377-49290974-5130http://imsear.searo.who.int/handle/123456789/223440Context: The programmed death-1 (PD-1) is an immune checkpoint molecule that suppresses T-cell response. The binding of PD-1 to PD-L1/PD-L2 results cytokine production, and T-cell proliferation are reduced. Tumors expressing PD-L1 and PD-L2 escape from cytotoxic T-cells and are exposed to tumor progression. For this reason, immunotherapy has become a new option in the treatment of cancer. Aims: In this study, we examined the PD-L1 and PD-L2 expression in colorectal carcinoma (CRC), and evaluated the relationship between clinicopathological parameters and CD8+ T cells. Methods and Material: We evaluated CD8 expression in tumor-infiltrating lymphocytes and surrounding tumor lymphocytes with PD-L1, PD-L2 staining in tumor cells and immune cells formalin-fixed paraffin embedded samples of 124 patient diagnosed with CRC. Statistical Analysis Used: Pearson Chi-Square, Fisher Exact Chi-Square, and Pearson Exact Chi-Square analyses were used in the analysis of the cross tables. Survival distributions predicted Kaplan--Meier method and it was evaluated using log-rank statistics. Results: In our study, a significant correlation was found between PD-L1 expression and female sex and tumors with medullary morphology. No expression of PD-L2 was observed in tumors containing medullary morphology, and a statistically inverse relationship was observed between PD-L2 and the medullary component. PD-L1 positive tumor-infiltrating lymphocytes were determined to be an important predictor for recurrence-free survival. Conclusions: We believe that the evaluation of these parameters may be useful in the selection of patients who will benefit from immunotherapy in CRC cases.Colorectal cancerimmunotherapyPD-L1PD-L2Journal ArticleIndiaAtatürk Public Hospital, Pathology, Antalya, TurkeyDepartment of Pathology, Medical Faculty, Osmangazi University, Eski?ehir, TurkeyDepartment of Medical Oncology, Medical Faculty, Osmangazi University, Eski?ehir, TurkeyDepartment of General Surgery, Medical Faculty, Osmangazi University, Eski?ehir, Turkey