Endometrial cancer (EC) is the most common gynaecological malignancy and its incidence is increasing. Dysregulation of the endometrial renin–angiotensin system (RAS) could predispose to EC; therefore, we studied the prevalence of RAS single nucleotide polymorphisms (SNPs) in Australian women with EC. SNPs assessed were AGT M235T (rs699); AGTR1 A1166C (rs5186); ACE A240T and T93C (rs4291, rs4292) and ATP6AP2 (rs2968915). They were identified using TaqMan SNP Genotyping Assays. The C allele of the AGTR1 SNP (rs5186) was more prevalent in women with EC (odds ratio (OR) 1.7, 95% confidence interval (CI) (1.2–2.3), P=0.002). The CC genotype of this SNP is associated with upregulation of the angiotensin II type 1 receptor (AGTR1). The G allele of AGT rs699, which is associated with higher angiotensinogen (AGT) levels, was less prevalent in women with EC (OR 0.54, 95% CI (0.39–0.74), P<0.001) compared with controls. AGT and AGT formed by removal of angiotensin I (des(Ang I)AGT) are both anti-angiogenic. In women with EC who had had hormone replacement therapy (HRT), the prevalence of the AGTR1 SNP (rs5186) and the ACE SNPs (rs4291 and rs4292) was greater than in women who had no record of HRT; SNP rs4291 is associated with increased plasma ACE activity. These data suggest there is an interaction between genotype, oestrogen replacement therapy and EC. In conclusion, the prevalence of two SNPs that enhance RAS activity was different in women with EC compared with healthy controls. These genetic factors may interact with obesity and hyperoestrogenism, predisposing ageing, obese women to EC.

A dysfunctional endometrial renin–angiotensin system (RAS) could aid the growth and spread of endometrial cancer. To determine if the RAS is altered in endometrial cancer, we measured RAS gene expression and protein levels in 30 human formalin-fixed, paraffin-embedded (FFPE) endometrioid carcinomas and their adjacent endometrium. All components of the RAS were expressed in most tumours and in adjacent endometrium; mRNA levels of (pro)renin receptor (ATP6AP2), angiotensin II type 1 receptor (AGTR1), angiotensin-converting enzyme (ACE1) and angiotensin-converting enzyme 2 (ACE2) mRNA levels were greater in tumour tissue than adjacent non-cancerous endometrium (P = 0.023, 0.008, 0.004 and 0.046, respectively). Prorenin, ATP6AP2, AGTR1, AGTR2 and ACE2 proteins were abundantly expressed in both cancerous and adjacent non-cancerous endometrium. Staining was most intense in cancerous glandular epithelium. One potential target of the endometrial RAS, transforming growth factor beta-1 (TGFB1), which is essential for epithelial-to-mesenchymal transition, was also upregulated in endometrial cancer tissue (P = 0.001). Interestingly, TGFB1 was strongly correlated with RAS expression and was upregulated in tumour tissue. This study is the first to characterise the mRNA and protein expression of all RAS components in cancerous and adjacent non-cancerous endometrium. The greater expression of ATP6AP2, AGTR1 and ACE1, key elements of the pro-angiogenic/proliferative arm of the RAS, suggests that the RAS plays a role in the growth and spread of endometrial cancer. Therefore, existing drugs that inhibit the RAS and which are used to treat hypertension may have potential as treatments for endometrial cancer.