PTEN and endometrioid adenocarcinoma: Another study 2 using a panel of ER, PR, p16, p53, and PTEN found that the majority of serous carcinomas are negative for ER and PR, positive for PTEN, diffusely positive for p16 and exhibit aberrant mutation-type expression (diffusely and strongly positive or entirely negative) with p53, whereas grade 3 endometrioid carcinomas are more likely to be positive for ER and PR, negative for PTEN (correlating with genetic aberrations of PTEN19), focally positive for p16 and show wild-type staining for p53.