CHEK1 and multinodular goiter: Separate analysis of a subset of the multinodular goiter samples with more aggressive PTC subtypes revealed 2 - 4-fold upregulation in the levels of CHEK1, c-MET and TIMP1, and a 2-4-fold downregulation of BCL2, c-KIT, TG and PPARγ (Table 4, lower part).