Correlation analysis of gene and immune microenvironment for 87 melanoma cases

e21555 Background: To map the genome of Chinese melanoma patients and explore its correlation with the expression of tumor immune microenvironmental indicators. Methods: Next generation sequencing was performed on 87 cases of primary melanoma that had been surgically removed from Nanjing Drum Tower Hospital from July 2010 to May 2017. Immunohistochemistry was carried out to detect the expressions of PD1, PDL1, CD3+TIL, MSH2, MSH6, PMS2 and MLH1. Results: BRAF mutations were the most common (26.4%), followed by KIT mutations (12.6%) in melanoma patients. RB1 gene copy number deletion (55%) and CDK4 (25%)/CCND1 (22.5%) gene copy number amplification were also common. The prognosis of patients could be distinguished by grouping the expression of PDL1 and TIL, and the difference may be related to the expression of PD1. There were more copy number amplication of genes with poor prognosis in PDL1-TIL- patients. Conclusions: The classification of tumors into four microenvironmental subtypes based on PDL1 and TIL expression is an appropriate method to stratify patients with different clinical outcomes. At the genetic level, there are more copy number amplification of the genes with poor prognosis in patients with TIL-PDL1- type, so the prognosis is always worse than that of patients with TIL+PDL1+ type. Gene may affect the prognosis of patients by affecting the tumor immune microenvironment.