The activity and expression of DCK varies widely in normal and malignant cells; furthermore, there is a 50-fold variation in DCK mRNA expression in patient leukemic cells, a 35-fold variation in DCK mRNA in primary AML cells, a 36-fold change in liver tissue and a 150-fold change in human liver metastases of colorectal cancer origin [185]. The gene discussed is DCK; the disease is colorectal cancer.