CHEK1 and papillary adenocarcinoma: The papillary adenocarcinoma also exhibited higher expression of BRCA1 and BRCA2, which are involved in DNA repair, Chk1 and Chk2 – highly mobile messengers which are capable of "globally" spreading the DNA-damage-induced signal throughout the nucleus [41], and the cyclin-dependent kinase inhibitor p18(INK4c) [42].