DLEC1 (Deleted in Lung and Esophageal Cancer 1) functions as a tumor suppressor gene and plays essential roles in both spermatogenesis and cancer biology. In reproductive biology, DLEC1 is required for male fertility, being significantly expressed in testes and germ cells 1. The protein is essential for proper sperm head and tail formation, with knockout mice showing impaired spermatogenesis, head deformation, shortened tails, and abnormal manchette organization 1. Mechanistically, DLEC1 interacts with tubulin, TRiC complex, and Bardet-Biedl Syndrome protein complex subunits, suggesting involvement in intraflagellar transport and ciliogenesis 1. In cancer, DLEC1 acts as a tumor suppressor by inhibiting cell proliferation and inducing G1 cell cycle arrest 2. The gene is frequently silenced through promoter hypermethylation in multiple cancer types including ovarian 3, hepatocellular 2, colorectal 4, lung 5, and nasopharyngeal carcinomas 6. DLEC1 methylation serves as a diagnostic biomarker with high sensitivity (0.90) and specificity (0.60) for lung cancer 5. Therapeutic agents like curcumin can restore DLEC1 expression through epigenetic demethylation, contributing to their anti-cancer effects 4.