MAEL (maelstrom spermatogenic transposon silencer) is a germline-specific protein with dual roles in spermatogenesis and cancer biology. Primarily, MAEL functions as a critical regulator of transposon silencing during spermatogenesis through the piRNA pathway 1. It localizes to P granules and piP-bodies, where it associates with piRNA-Piwi protein complexes to repress transposable elements and maintain genomic stability 2. Beyond its canonical germline function, MAEL is expressed in mitochondria of ejaculated spermatozoa, where it regulates ATP production and sperm motility through interactions with GPX4 and UBL4B 3. Biallelic MAEL variants cause transposon de-repression and impaired spermatogenesis, establishing piRNA pathway disruption as a major cause of human male infertility 1. Clinically, MAEL functions as a cancer/testis-associated gene, with elevated expression in multiple malignancies including clear cell renal carcinoma and breast cancer 4. In breast cancer, MAEL promotes metabolic reprogramming by facilitating chaperone-mediated autophagy-dependent degradation of Krebs cycle enzymes 5. High MAEL expression in clear cell renal carcinoma predicts favorable responses to VEGFR/mTOR inhibitors but poor outcomes with immunotherapy 4. MAEL expression is regulated by DNA methylation in its promoter region 6.