Features of omental adipose tissue in endometrial cancer patients with ‘standard’ or ‘metabolically healthy’ obesity: associations with tumor process characteristics

PURPOSE Adipose tissue products may contribute to endometrial cancer (EC) initiation and further growth that encourages the analysis of this issue in patients with different obesity phenotypes. METHODS/PATIENTS Omental fat depot characteristics were studied in EC patients (n = 57) with "standard" (SO) or "metabolically healthy" (MHO) obesity. Collected omental samples were evaluated by immunohistochemistry /IHC/ for brown fat marker UCP1, CYP19 (aromatase) and macrophage infiltration markers (CD68, CD163, crown-like structures/CLS) expression. Total RNA extracted from the same samples was investigated for UCP1, CYP19, PTEN and adipokine omentin mRNA. RESULTS Immunohistochemistry data revealed a statistically significant increase in aromatase and CD68 expression and tendency to increase of UCP1 expression in SO patients' omental fat compared to samples obtained from MHO patients. Additionally, positive correlation of EC clinical stage with UCP1 protein and its mRNA content in omental fat was pronounced in MHO as well as SO group, while with omentin mRNA it was discovered only in patients with SO. An inclination to the correlation with better tumor differentiation was seen for UCP1 and CD68 protein expression in patients with MHO and with worse (high grade) differentiation-for CD68 expression in the group with SO. CONCLUSIONS In aggregate, this suggests that obesity phenotype has significant impact on omental fat tissue characteristics which is related to the clinical course of EC and may have practical consequences.