Head and neck cancers represent more than 500,000 cases per year worldwide, and often involve post-treatment relapse. The oral cavity is the most frequent site, but early disease stages are still insufficiently characterised and poorly detected. The study's aim is to better understand the oral mucosa somatic evolution, and how it can give rise to oral squamous cell carcinoma (OSCC).

This is a multi-centric, descriptive, non-interventional cohort in healthy adult subjects. The aim of the study is to detect the presence of OSCC driver gene mutations in healthy subjects' oral mucosa, quantify whether they provide cells with a selective advantage, and study the impact of tobacco and alcohol consumption on the mutational load. This study will not allow to identify potential malignant cells, and will be usable for diagnostic purposes.

Inclusion Criteria:

• Man or woman aged 18 or more.
• Subject coming to odontology practice for routine visit.
• Subject having accepted to participate to the research by oral non-opposition
• Subject having given additional written consent for genetic studies.
• Smoking group criterion: subjects having smoked 100+ cigarettes/joints during their life.

Exclusion Criteria:

• Personal history of cancer, whichever the type.
• Treatment with anticoagulants or platelet aggregation inhibitors.
• Bilateral lesions of the inner cheek preventing painless biological sample collection.
• Subject under under guardians or curators
• Pregnancy or breastfeeding
• Cannabis usage

Subjects coming to odontology practices for routine visits