For dendritic cells, CD62L− Dendritic Cell Absolute Count was confirmed to be positively correlated with the risk of prostate cancer through IVW analysis (IVW: OR = 1.0016; 95%CI:1.0005–1.0026; p = 0.0039), with no significant association in MR-Egger and weighted median, and no evidence of horizontal pleiotropy in the MR-Egger intercept assessment (p = 0.7088) as well as MR-PRESSO global test analysis (p = 0.4650). The gene discussed is SELL; the disease is Familial prostate cancer.