Cancer Stem Cells in Moderately Differentiated Oral Tongue Squamous Cell Carcinoma Express Components of the Renin-Angiotensin System

Authors: Tinte Itinteang, Jonathan C. Dunne, Alice M. Chibnall, Helen D. Brasch, Paul F. Davis and Swee T. Tan

 Journal of Clinical Pathology, 2016;69:942-945

Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer of the mouth. In a previous publication we identified two distinct subpopulations of cancer stem cells (CSCs) within tongue cancers, distributed within different areas of the tumour.

The renin-angiotensin system (RAS) has long been associated with blood pressure regulation, but recent publications suggest it has a role in cancer growth. Its major components, angiotensin converting enzyme (ACE), angiotensin II receptor 1 (ATIIR1) and angiotensin II receptor 2 (ATIIR2) have been demonstrated within several different cancers. The implication of this discovery is that there may be a role for the RAS in cancer formation. Consequently, the GMRI has investigated the expression of the RAS components in tongue cancer, in particular whether they are associated with the two different subtypes of CSCs.

Within both subtypes of CSCs, the ATIIR1 and ATIIR2 and also the pro-renin receptor (PRR) were identified. PRR, ATIIR1 abd ATIIR2 are present in the CSCs while ACE was found to be present in the cells lining the small blood vessels, in tongue cancer. This is consistent with the general pattern of expression of RAS constituents that has been seen in several other cancers. It suggests there may be novel treatment approaches for this cancer by using medications that inhibit the RAS.