Exploring the causal relationship between immune cell characteristics and melanoma: A two-way Mendelian randomization study.

Melanoma skin cancer occurs mostly in melanocytes, with a high degree of malignancy and poor prognosis. The continuous development of Mendelian stochastic analysis in the field of medicine has led to the discovery of new therapeutic genes and drug targets for many diseases. Therefore, we aim to discover more possible melanoma therapeutic targets through Mendelian randomization analysis. Based on the published genome-wide association study data, 2-sample MR was used to analyze the 2-way causal relationship between 731 immune cell characteristics and melanoma skin cancer. The results of the inverse variance weighted method were used as the main screening criteria to obtain the characteristics of immune cells associated with melanoma. Heterogeneity analysis, multiplicity analysis and one-to-one elimination test also ensure the robustness and sensitivity of the results. We obtained 26 related immune cell characteristics, of which 15 immune cell characteristics are protective factors for melanoma. Including CD25 on transitional B cell, switched memory B cell, IgD+ CD38- B cell, BAFF-R on transitional B cell, CD38 on IgD+ CD38dim B cell, CD24+ CD27+ B cell, CD39+ activated CD4 regulatory T cell, BAFF-R on IgD- CD38- B cell, BAFF-R on IgD+ CD38+ B cell, CD28 on CD4 regulatory T cell, CD66b on CD66b++ myeloid cell, CD25 on CD24+ CD27+ B cell, BAFF-R on switched memory B cell, CD11b on granulocytic myeloid-derived suppressor cells and CD4RA on terminally differentiated CD4+ T cell. 11 immune cell characteristics were risk factors, including CD14+ CD16- monocyte, CD25++ CD45RA- CD4 not regulatory T cell absolute count, activated CD4 regulatory T cell absolute count, CD39+ CD8+ T cell absolute count, CCR2 on myeloid dendritic cell, CD127 on CD45RA+ CD4+ T cell, CD11c+ monocyte, CD3 on central memory CD8+ T cell, CD4+/CD8+ T cell, CD3 on HLA DR+ CD4+ T cell and CD4- CD8- T cell. Reverse analysis showed that melanoma had no effect on immune cell characteristics. Our study used MR method to analyze the causal relationship between 731 immune cell characteristics and melanoma from a genetic point of view, which provides more possible ways for the treatment of melanoma patients.