STPG1 (sperm tail PG-rich repeat containing 1) is a gene with emerging roles in apoptotic regulation and immune-mediated tumor suppression. According to UniProt annotations and GO terms, STPG1 positively contributes to apoptosis induction, particularly through promotion of mitochondrial membrane permeability changes [UniProt]. In gastric cancer, STPG1 functions downstream of the transcription factor ThPOK, which directly binds the STPG1 promoter to upregulate its expression 1. Mechanistically, STPG1 upregulation suppresses gastric cancer cell viability and promotes T cell activation by inactivating the ERK signaling pathway 1. This suggests STPG1 acts as a tumor suppressor by inhibiting cancer cell immune escape. Clinically, STPG1 expression is downregulated in gastric cancer tissues and cells, correlating with reduced immunogenicity 1. The gene has also been identified as a novel fusion partner with KMT2A in rare acute myeloid leukemia cases 2, indicating potential oncogenic roles in specific translocation contexts. While STPG1 disruption by chr1 translocation has been observed in familial balanced translocation carriers, no clear pathogenic correlation was established 3. Overall, STPG1 represents a multifunctional regulator linking apoptosis, immune activation, and potential cancer suppression.