Moreover, we have found that in the N/TERT immortal keratinocyte cell line with suppressed levels of p16INK4A and compromised checkpoint mechanism [11], FOXM1B expression downregulated the levels of p21cip1 (data not shown), suggesting a clear difference between primary and cancer cell lines in terms of response to FOXM1B expression. The gene discussed is CDKN1A; the disease is cancer.