Alterations of pRb1-cyclin D1-cdk4/6-p16(INK4A) pathway in endometrial carcinogenesis.

The retinoblastoma protein pathway (pRb1-cyclin D1-cdk4/6-p16(INK4A)) participates in the regulation of the cellular processes at the transition of G1/S phases of the cell-cycle. Derailments of this pathway, caused either by lack of pRb1 or p16(INK4A) expression or overexpression of cyclin D1 and/or cdk4/6, are implicated in the deregulation of the cell-cycle machinery, resulting in uncontrolled cell proliferation, tumor heterogeneity, invasion and metastasis. Several studies conducted so far have assessed the deregulation of the pRb1-pathway components in various human tumors and cell-lines, provided these pathway alterations play an obligatory role in tumorigenesis. This review briefly summarizes the current information on the pRb1-cyclin D1-cdk4/6-p16(INK4A) alterations in sporadic uterine cancer, placing emphasis on the influence on the dualistic model of endometrial carcinogenesis.