Then, in 1997, several laboratories identified a putative tumor-suppressor gene at 10q23 that encodes a 403 amino acid protein with a protein-tyrosine-phosphatase domain and homology to chicken tensin and bovine auxilin, which was then named PTEN for phosphatase and tensin homolog deleted on chromosome 10 [6,7,8,9]. The gene discussed is PTEN; the disease is neoplasm.