Correlation analysis between CXC chemokine receptor 6 and prognosis of renal clear cell carcinoma

Objective To investigate the correlation between CXC chemokine receptor 6 (CXCR6) and prognosis of renal clear cell carcinoma. Methods A total of 100 patients with renal clear cell carcinoma who underwent surgery in the First People's Hospital of Ziyang from January 2013 to October 2014 were selected. Immunohistochemistry was used to detect the expression of CXCR6 in 100 cases of renal clear cell carcinoma and adjacent normal tissues. The patients were followed up to observe the positive rate of CXCR6 expression and the factors affecting overall survival (OS) and progression-free survival (PFS) of renal clear cell carcinoma and adjacent normal tissues. Results The positive rate of CXCR6 expression in renal clear cell carcinoma tissues was higher than that in adjacent tissues, and the difference was statistically significant [46.0% (46/100) vs. 20.0% (20/100), χ2 = 15.287, P < 0.01]. The positive expression rate of CXCR6 in patients with clinical stage Ⅲ-Ⅳ, lymph node metastasis and pathological grade Ⅲ-Ⅳ was higher than that in patients with clinical stage Ⅰ- Ⅱ, pathological grade Ⅰ- Ⅱ and without lymph node metastasis, and the difference was statistically significant (all P < 0.05). A total of 92 patients were followed up and 40 died. The follow-up time reached to (35-60) months and the median follow-up time was 48.9 months. Kaplan-Meier and log-rank test showed that patients with positive CXCR6 expression had lower 3-year OS and PFS rate compared with patients with negative CXCR6 expression, and the difference was statistically significant (3-year OS rate: 52.1% vs. 78.6%, χ2 = 10.027, P = 0.001; 3-year PFS rate: 48.3% vs. 67.8%, χ2 = 4.344, P = 0.037). Cox regression multivariate analysis showed pathological grade (OS: OR = 2.154, 95% CI 1.547-9.517, P = 0.023; PFS: OR = 1.235, 95% CI 1.109-5.917, P = 0.042), lymph node metastasis (OS: OR = 1.412, 95% CI 1.109-5.917, P = 0.041; PFS: OR = 1.841, 95% CI 1.354-8.994, P = 0.010), CXCR6 expression (OS: OR = 1.864, 95% CI 1.358-6.813, P = 0.031; PFS: OR = 1.457, 95% CI 1.127-6.884,P = 0.025) were independent risk factors of OS and PFS for renal clear cell carcinoma patients treated by the surgery. Conclusions The positive expression of CXCR6 is an independent risk factor for OS and PFS of renal clear cell carcinoma. The prognosis of patients with positive CXCR6 expression is poor. Key words: Carcinoma, renal cell; Receptors, chemokine; Prognosis