Immunohistochemical characterisation of molecular subtypes in endometrial cancer.

Four molecular subtypes have lately been established in endometrial cancer basing on estrogen receptor (ER), progesterone receptor (PR) and HER2 status: ER+/PR+/HER2+, ER+/PR+/HER2-, ER-/PR-/HER2+ and ER-/PR-/HER2-. The subtypes have shown diversity in terms of prognosis, clinicopathological and molecular characteristics, with ER+/PR+/HER2- and ER-/PR-/HER2+ group exhibiting exceptionally benign and aggressive behavior, respectively. We have further characterized the subtypes in the context of pathways known to drive endometrial carcinogenesis: phosphatidylinositol 3-kinase (PI3K)-AKT pathway (ERBB/PI3K pathway), TP53 system, and the mismatch repair (MMR) mechanism.