Tobacco, Alcohol and Cancerization of the Oral Mucosa (TACO)

Epidermoid carcinomas of upper aerodigestive tract are the 8th most common cancers in the world. Worldwide, this represents more than 500.000 cases per year and 20.000 cases per year in France (statistics 2018-2020). Among these cancers, oral squamous cell carcinoma (OSCC) are the most common location, leading to significant morbidity and mortality. Despite recent advances in diagnosis, treatment and monitoring, the overall 5-year survival rate of patients with epidermoid carcinomas of upper aerodigestive tract has not improved significantly and remains around 40-50 % for all combined locations. These pejorative survival rates, as well as the increase in the incidence of these cancers, have not changed much over the past 30 years. This situation can be attributed in part to a diagnosis too late. Indeed, only 1/3 of patients with high-risk squamous cell carcinoma of the head and neck are diagnosed at an early stage. This issue of early diagnosis is mainly due to the lack of suitable screening and diagnostic biomarkers. Beyond diagnosis, the identification of biomarkers is also a prognostic and predictive interest since they could predict the course of the disease as well as the response to treatment. "Drivers" mutations, with oncogenic potential, can be present from the very early stages of epidermoid carcinomas of upper aerodigestive tract and therefore constitute potential biomarkers. However, recent studies have demonstrated the presence of driver mutations in different types of oral cavity's healthy tissue, some being even associated with a protective effect against tumor initiation. In order to improve prevention and early diagnosis of OSCC, it is important to better understand the evolutionary dynamics of somatic mutations in the oral mucosa, which is still poorly characterized.