In general, ALDH1A1 has prognostic value as a marker in patients with head and neck squamous cell carcinoma.39 Recent studies have demonstrated that ALDH1A1 expression is reduced in 25.5% (11/43) of SQCC40 cases, and the loss of ALDH1A1 expression may promote carcinogenesis, especially in smoking patients. The gene discussed is ALDH1A1; the disease is head and neck squamous cell carcinoma.