Figure 5 shows representative immunohistochemical images of lymph vessels in the surrounding tissue. In cases where PROK1 expression was not observed in the primary colorectal cancer tissue, the number of lymph vessels was 33 per visual field in the surrounding skin tissue, whereas the number of lymph vessels significantly increased to 59.5 per visual field in the surrounding skin tissue of patients with high PROK1 expression, demonstrating lymphangiogenesis (Figure 5). Here, PROK1 is linked to colorectal cancer.