CDKN1B and carcinoma: We also observed loss of p21Cip1 and p18INK4c expression in pancreatic islet tumors from both Men1–/– (n = 4; 2 adenoma and 2 carcinoma) and hTS/Men1–/– mice (n = 4; 2 adenoma and 2 carcinoma), while p27Kip1 expression was not affected (Supplemental Figure 5).