The relationship between Pim-3 expression and chemoradiotherapy resistance in locally advanced rectal cancer patients.
e15112 Background: It is difficult for clinical oncologists to predict which types of rectal cancer patient would respond to neoadjuvant chemoradiotherapy. About 30% of rectal cancer patients who could not benefit from chemoradiotherapy, and about 10% of patients even suffered from disease progression. It is of considerable importance to identify a bio-marker to identify patients who would benefit from neoadjuvant treatment. Methods: This study enrolled 175 rectal cancer patients who underwent neoadjuvant treatment. Tissue samples from all the patients were deposited in the tissue bank of Sun Yat-sen University Cancer Center prior to neoadjuvant treatment. We compared the expression of Pim-3 in rectal tumors and investigated correlations with the response to chemoradiotherapy and with survival. Results: The Pim-3-negative patients were more likely to achieve a pathological complete response to chemoradiotherapy (P = 0.001, RR = 5.132, 95% CI: 2.442–10.787). Cox multivariate analysis in 137 patients with at least 24 months follow-up showed that the expression of Pim-3 (P = 0.041, RR = 1.209, 95% CI = 1.007–1.452) and cycles of neoadjuvant chemotherapy cycles (P = 0.006, RR = 0.557, 95% CI = 0.367–0.845) were significant factors affecting the survival status of patients. Cox multivariate analysis of disease-free survival showed that Pim-3 expression (P = 0.012, RR = 1.180, 95% CI: 1.037–1.344) and adjuvant chemotherapy cycles (P = 0.003, RR = 0.745, 95% CI: 0.615–0.902) were statistically significant factors. Conclusions: Pim-3 could be a potential predictive bio-marker of the response to chemoradiotherapy.