CAL27 and CAL33 are well studied cell lines that have known aberrations/mutations in classical HNSCC genes such as TP53 (CAL27/CAL33), PIK3CA (CAL33), FAT1 (CAL27/CAL33), CASP8 (CAL33), etc. [13]. The gene discussed is PIK3CA; the disease is head and neck squamous cell carcinoma.