Kulsum et al. found that HNSCC cell lines resistant to cisplatin and 5-FU showed enrichment of CD44+ ALDH1+ subpopulation, stemness, expression of ABCG2, Sox2, Nanog, Oct4, and NOTCH1 genes, and G0/G1 or S phase arrest[113]. This evidence concerns the gene ALDH1A1 and head and neck squamous cell carcinoma.