PIWIL2 also known as HILI, CT80 is a member of the argonaute family, characterized by the presence of one PAZ domain and one PIWI domain. This cytoplasmic protein is predominantly expressed in adult testis and various tumors, playing a crucial role in regulating spermatogenesis and the production of primordial germ cells. PIWIL2 is involved in the meiotic differentiation of spermatocytes and the self-renewal of spermatogonial stem cells, which is vital for maintaining male fertility. PIWIL2 interacts with several key proteins that influence cellular processes, including PDGFR-β, which is associated with stem cell proliferation, and Glut1, which is involved in energy metabolism. PIWIL2 may act as a regulatory factor in the Stat3/Bcl-xS/L/CCND1 signaling pathway, and PIWIL2 repression has been shown to inhibit tumor cell growth, highlighting a potential role as an oncogene by promoting proliferation and inhibiting apoptosis in cancerous cells.