Clinicopathologic evaluation of CD80, CD86 and PDL-1 expressions with immunohistochemical methods in malignant melanoma patients

Malignant melanoma is a highly immunogenic tumor that develops from melanocytes. The presence of tumor-infiltrating lymphocytes and the observation of spontaneously regressed areas in resected melanoma specimens have made melanoma a possible target for immunotherapy. We aimed to determine the expression ratios of CD80, CD86 and PD-L1 as a result of immunohistochemical evaluation of specimens collected by biopsy or surgical resection between 2005 and 2015 and to investigate the correlation between these markers and clinical features such as stage and survival. 5 years survival rates was significantly higher in CD80 positive patients and CD86 positive patients. In patients with higher CD80 staining score, survival was significantly higher. However, there were no relationship between CD86 staining scores and survival. In patients with low tumoral PDL-1 staining scores, survival was significantly higher, whereas no correlation was found between lymphocytic PDL-1 staining scores and survival. Based on our results, we suggest that tumoral PDL-1 staining scores, CD80 positivity, CD86 positivity, CD80 staining scores and CD86 staining scores in tumors should be considered as prognostic markers and that these criteria should be taken into consideration in the clinical management of patients.