Finally, the expression of p15INK4b, p19INK4d and p21CIP/WAF1 was decreased in transfected MTC-SK cells, whereas the protein levels of p16INK4a, p18INK4c and p27KIP1 were not significantly changed (Figure 4C). The gene discussed is CDKN2C; the disease is medullary thyroid gland carcinoma.