PIK3CA and neoplasm: To understand if the neoplastic transformation of the gallbladder epithelium in the Pten+/− mice was exquisitely dependent on the hyperactivation of the PI3K/AKT pathway, or some combination of the multiple tumor suppressive function of PTEN, we analyzed a specific cohort of knock-in mice carrying the Pten-G129E mutant allele in heterozygosity [21].