CDKN1A and squamous cell carcinoma: MART-10 was found to show greater potential than calcitriol in suppressing FaDu and SCC-25 squamous carcinoma cell lines; this occurred through increased cell cycle arrest at G0/G1, accompanied by a greater downregulation of Ki-67 expression and upregulation of p21WAF1/CIP1 and p27KIP1.