APOE and male infertility: The STRING algorithm analysis identified several genes closely related to APOB that may actively contribute to male infertility, including APOC3, APOA1, LDLR, LPL, APOA2, MTTP, LPA, and SORT1. LPL is essential for steroidogenesis and proper sperm membrane lipid release [31], while LDLR and APOE knockout have been associated with disturbed testosterone production [32, 33].