ALDH1A1 and head and neck squamous cell carcinoma: In head and neck squamous cell carcinoma (HNSCC), ALDH1A1 was enriched in cisplatin and 5-fluorouacil-resistant squamous cell carcinoma (SCC) Cal-27 cell lines, which displayed enhanced stemness features such as spheroid formation, clonogenicity, and migratory potential [42].