We hypothesised that the blood levels of immune cells would be related to the progression of colorectal cancer and regional lymph node metastasis. We investigated the association between the blood levels of immune cells and regional lymph node metastasis in colorectal cancer patients. Patients with American Joint Committee on Cancer (AJCC) stages 1 and 2 colorectal cancer were assigned to Early stage group and those with AJCC stages 3 and 4 were assigned to Late stage group. Blood levels of circulating immune cells, such as cluster of differentiation (CD)4+ including T helper 1 (Th1) and 17 (Th17) cells, regulatory T (Treg) cells, CD8+ T cells, and natural killer (NK) cells were assessed using fluorescence-activated cell sorting (FACS). The blood levels of CD4+ T, Treg, CD8+ T, and NK cells did not significantly differ between the two groups. However, the blood levels of Th1 and Th17 cells did significantly differ between the groups. Specifically, Late stage group had higher levels of Th1 and Th17 cells than Early stage group (Th1, 11.14±1.22% vs. 16.25±1.57%, p = 0.015; Th17, 3.32±0.05% vs. 1.11±0.15%, p < 0.01). In conclusion, the blood levels of Th1 and Th17 cells significantly increased as the N stage increased. The blood levels of Th1 and Th17 cells might be useful as predictive markers of lymph node invasion in colorectal cancer.
Keywords: colorectal cancer; helper T cell.; immune cell; lymph node metastasis.