Prognostic value of CCR7 expression in gastric cancer

Chemokine receptor CCR7 is a key molecule for migration of lymphocytes and dendritic cells into lymph nodes. Expression of CCR7 in tumor cells has been reported in malignancies, and CCR7 expression in tumor cells has been investigated in vitro and in vivo. However, there is little information regarding the clinical implications of CCR7-positive gastric cancer.

A total of 224 gastric cancer patients who underwent curative surgery in Kagoshima University Hospital were enrolled. CCR7 expression in the primary tumor was detected by immunohistochemically. Patients showing more than 10% positivity for CCR7 were defined as having high CCR7 expression, as previously reported.

CCR7 expression was detected in cytoplasm and membrane of tumor cells and inflammatory cells in the tumor nest. CCR7-positive patients exhibited deeper tumor invasion, more frequent lymph node metastasis, higher rates of lymphatic invasion (p < 0.01) and more venous invasion (p < 0.05) than CCR7-negative patients. Multivariate regression analysis showed that the most significant clinical factor for CCR7 was lymph node metastasis followed by lymphatic invasion. CCR7-positive gastric cancer patients had significantly poorer surgical outcomes than CCR7-negative patients (p < 0.01). However, CCR7 was not selected as an independent prognostic factor.

Our results suggest that CCR7 expression in gastric cancer is related to the onset of preferential conditions for lymphatic spread, such as lymph node metastasis. Although CCR7 expression is not an independent prognostic factor, it may show strong correlations with other lymphatic factors. CCR7 expression of preoperative biopsy specimen can predict lymph node metastasis because of the close correlation with lymphatic factors.