Oral cavity cancers are one of the 6 most common cancers worldwide, 90% of which are squamous cell carcinoma (SCC). Cancer stem cells (CSCs) are cells within cancer that have been proposed to give rise to and are critical for the spread of cancer. Our research team have shown the renin-angiotensin system (RAS), a hormonal system, critical in regulating tumour stem cells in strawberry birthmarks. This research aims to identify and characterise CSCs in oral cavity squamous cell carcinomas (OCSCCs) and the involvement of RAS, initially focussing on oral tongue SCC and then comparing the findings with SCCs of affecting different sub-sites of the oral cavity, such as the lip, floor of mouth, and palate. A better understanding of the role of available medications that modulate the RAS on CSCs in OCSCCs, may lead to effective treatment for patients affected by OCSCCs for which current treatments are only partially effective.