MLH1 and thyroid gland papillary carcinoma: In previous studies of papillary thyroid cancer, although methylation of RASSF1A and BRAF mutation were detected in a mutually exclusive manner (Xing et al., 2004; Hoque et al., 2005), methylation of RAR-β2 or MLH1 significantly correlated to BRAF mutation (Hoque et al., 2005; Guan et al., 2008).