Interestingly, the expression of Chk1 protein positively correlated to tumor grade (P < 0.001), tumor type (P = 0.001), and tumor size (P = 0.012), and in addition to expression of the proliferation marker Ki67 (P < 0.001; Table 2), suggesting that Chk1 is a marker for tumor aggressiveness. Here, CHEK1 is linked to neoplasm.