Table 2. Risk factors for endometrial hyperplasia.

Risk factor	Factor inducing endometrial hyperplasia
Menstrual and parity status	Postmenopausal, null parity, late menopause or early menarche, chronic anovulation
Pre-existing disease	Obesity/overweight/high body mass index, diabetes mellitus, infertility, hypertension, polycystic ovarian syndrome, androgen-secreting tumors, hereditary non-polyposis colonic cancer (Lynch syndrome)
Hormone therapy	Prolonged exogenous estrogen exposure, tamoxifen, estrogen replacement therapy
Genetic factors	SNPs (CYP2D6, CYP17, COMT, APOE, and HFE), PTEN, K-ras, β-catenin, PIK3CA mutations, deletions on the short arm of chr-8, MSI
Inflammatory markers and cytokines	TNF-α, PCNA, EGF, Fas, TNF-R1, IGF-1, NF-κB, IL-22

APOE, apolipoprotein E; chr-8, chromosome 8; COMT, catechol-O-methyltransferase; CYP17, cytochrome P450 17A1; CYP2D6, cytochrome P450 2D6; EGF, epithelial growth factor; HFE, hemochromatosis; IGF-1, insulin-like growth factor 1; IL-22, interleukin 22; NF-κB, nuclear factor-κB; MSI, microsatellite instability; PCNA, proliferating cell nuclear antigen; PIK3CA, phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform; PTEN, phosphatase and tensin homolog; SNP, single nucleotide polymorphism; TNF-α, tumor necrosis factor-α; TNF-R1, tumor necrosis factor receptor 1.