Table 2

Features of endometrial precancers

Precancers differ from normal tissueMonoclonal precancers12,21,23,25 arise from a polyclonal normal field24
Mutations are acquired in precancers23,38,49–53
Precancers share some, but not all, features of cancerPrecancer–cancer lineage hierarchy26
May share PTEN,37,38,55 K-ras,52–54,56 MLH151,57 changes
Both are monoclonal21,23,25,58,59
Precancers increase risk for carcinomaIncreased concurrent cancer rate30
Increased future cancer rate31,32
Precancers can be diagnosedMorphometric standard21,22,29,50
Endometrial intraepithelial neoplasia = precancers (table 1)
Hormonal and genetic risks are linkedHormonal modulation of the PTEN gene,45 frequently inactivated in premalignant disease37,38,41,53
Precancers can be induced by manipulating genetic and/or hormonal variables100% of PTEN mutant heterozygote mice get endometrial “hyperplasia” and 21% of these evolve to carcinoma60