CXCL10 mRNA expression predicts response to neoadjuvant chemoradiotherapy in rectal cancer patients.

Chemoradiotherapy has been commonly used as neoadjuvant therapy for rectal cancer to allow for less aggressive surgical approaches and to improve quality of life. In cancer, it has been reported that CXCL10 has an anti-tumor function. However, the association between CXCL10 and chemoradiosensitivity has not been fully investigated. We performed this study to investigate the relationship between CXCL10 expression and chemoradiosensitivity in rectal cancer patients. Ninety-five patients with rectal cancer who received neoadjuvant chemoradiotherapy (NCRT) were included. Clinical parameters were compared with the outcome of NCRT and CXCL10 messenger RNA (mRNA) expression between the pathological complete response (pCR) group and non-pathological complete response (npCR) group. CXCL10 mRNA and protein expressions between groups were analyzed using the Student's t test and chi-square test. The mean mRNA level of CXCL10 in the pCR group was significantly higher than that in the npCR group (p = 0.010). In the pCR group, 73.7 % of the patients had high CXCL10 mRNA expression, and 61.4 % of the patients in the npCR group had low CXCL10 mRNA expression. Subjects with high CXCL10 mRNA expression demonstrated a higher sensitivity to NCRT (p = 0.011). The receiver operating characteristic curve showed that the diagnostic performance of CXCL10 mRNA expression had an area under the curve of 0.720 (95 % confidence interval, 0.573-0.867). There were no differences between the pCR and npCR groups in CXCL10 protein expression (p > 0.05). High CXCL10 mRNA expression is associated with a better tumor response to NCRT in rectal cancer patients and may predict the outcome of NCRT in this malignancy.