PROK1 and metastatic malignant neoplasm in the lymph nodes: The findings of the present study show that PROK1 expression and growth of lymphatic endothelial cells are correlated, and the incidence of lymph node metastasis is greater in patients with PROK1 expression in the primary tumor lesion, compared to those with non-detectable PROK1 expression in human colorectal cancer.