NKD1 and malignant colon neoplasm: Transfection of the NKD1 gene or the calcium deficient mutant gene in SW620-nkd1−/− cells significantly increased the number of JC-1 aggregates, whereas transfection of the EF-hand deficient mutant gene only slightly increased the number of JC-1 aggregates (Fig. 7A), suggesting that the EF-hand domain is the key component of NKD1 protein in the inhibition of colon cancer cell apoptosis.