PTEN and prostate intraepithelial neoplasia: Substitution of alanine 662 and asparagine 664 for cysteine residues in Stat3 promotes its dimerization and generates a constitutively-active transcription factor (Stat3C) [139], with PB promoter-driven Stat3C expression promoting the development of PIN lesions while invasive adenocarcinoma developed when combined with Pten heterozygosity [140].