The prognostic role of the host immune response in rectal cancer patients treated with neoadjuvant chemoradiation.

575 Background: The development of metachronous distant metastasis is – despite remarkable progress - still a challenging problem after multimodality treatment of rectal cancer. The host immune response has been identified as a valid prognostic marker in primary colon cancer but not in rectal cancer after neoadjuvant chemoradiotherpy so far. Methods: We analysed the mRNA and protein expression of the B- and T-cell chemokines CXCL13 and CXCL9 as well as the B-cell marker IGHM in 77 rectal cancer specimens undergoing preoperative chemoradiotherapy and investigated the role of the host immune response on the occurrence of distant metastasis and survival. Results: The intratumoral mRNA expression levels of the T-cell activator CXCL9 (p < 0.001) as well as the B-cell chemokine CXCL13 (p < 0.01) were inversely correlated with the development of distant metastasis. Patients with high CXCL9 (p < 0.0001) or CXCL13 expression (p < 0.01) had a significantly prolonged DFS. Moreover, patients with high mRNA levels of ...