Abstract: Objective To investigate the expressions of hypoxia-inducible factor-1α (HIF-1α) and apoptotic inhibitory protein Survivin in rectal cancer tissues and their predictive values for tumor regression after neoadjuvant chemoradiotherapy. Methods A retrospective analysis was performed on 83 rectal cancer patients who underwent total mesorectal resection (TME) after neoadjuvant radiotherapy and chemotherapy in our hospital from April 2014 to August 2018. Immunohistochemical method was used to detect the expressions of HIF-1α and Survivin in tumor tissues. Spearman rank correlation test was performed to analyze the relationship between HIF-1α and Survivin expressions. AJCC-TRG scoring system was employed to evaluate the effect of tumor regression after radiotherapy and chemotherapy. The relationship between tumor regression and HIF-1α/Survivin was analyzed. Results Immunohistochemistry showed that the positive expression rates of HIF-1α and Survivin in cancer tissues were 61.4% (51/83) and 67.5% (56/83), respectively. Expressions of HIF-1α and Survivin were positively correlated, and the spearman correlation coefficient was rs=0.587 (P＜0.001). The total effective rate of patients after neoadjuvant therapy was 55.4% (46/83), with 13 cases of complete withdrawal, 33 cases of moderate withdrawal, 20 cases of mild withdrawal and 17 cases of non-withdrawal. Analysis showed that the expressions of HIF-1α and Survivin were correlated with tumor regression. The effective rate of patients with HIF-1α (+)/Survivin (+) was 35.3% (12/34), which was significantly lower than that of other groups. Conclusion There is a positive correlation between the expressions of HIF-1α and Survivin in rectal cancer tissues. The expressions of HIF- 1α and Survivin can provide a basis for predicting the regression effect after neoadjuvant chemoradiotherapy in rectal cancer.

Key words: rectal neoplasms, hypoxia-inducible factor 1, alpha subunit, chemoradiotherapy, adjuvant, Survivin, tumor regression