The significance of the altered expression of lysophosphatidic acid receptors, autotaxin and phospholipase A2 as the potential biomarkers in type 1 endometrial cancer biology.

In order to study lysophosphatidic acid (LPA) signaling associated with type 1 endometrial carcinoma (EC), we evaluated the LPA receptors (LPARs), autotaxin (ATX) and phospholipase A2 (PLA2) expression in EC and normal endometrium with correlation to clinicopathological features. We investigated LPAR1, LPAR2, LPAR3, LPAR4, ATX and PLA2 expression at mRNA and protein levels using quantitative real-time PCR and western blot analyses in 37 ECs and 10 normal endometria. All the examined LPARs (except for LPAR3 protein), ATX and PLA2 were overexpressed in cancerous compared to healthy endometrium. The studied ECs showed the highest LPAR2 and LPAR1 expression. Statistically positive correlations were found between depth of myoinvasion and levels of LPAR1, LPAR2 and PLA2 transcripts and proteins. We also found positive correlations between LPAR1, LPAR2, LPAR4 and PLA2 expression with the International Federation of Gynecology and Obstetrics (FIGO) stage. The expression of LPAR1, LPAR2 and PLA2 was positively associated with the age of patients. Positive correlations were found between the expression of LPAR1 mRNA, LPAR2 mRNA and protein and LPAR3 mRNA and body mass index (BMI) of the examined patients. We found no association between the expression levels of the studied factors and diabetes or hypertension among the examined patients. Owing to the highest LPAR2 and LPAR1 expression in EC and positive correlations of these two receptors with the depth of myoinvasion and the FIGO stage, we believe that LPAR2 and LPAR1 show promise as predictors of the EC progression as well as the main receptors responsible for LPA action in the EC tissue.