PTEN and endometrial carcinoma: Since microsatellite instability is a highly frequent event in endometrioid EC, Wang et al. established a transgenic mouse system that harbors a homozygote MLH−/− deletion next to the heterozygous PTEN loss (PTEN+/−) and showed an accelerated onset of endometrial carcinoma [18,108], confirming the role of microsatellite instability in EC.