In the present study, we analyzed the supra-additive effect of oxaliplatin in combination with gemcitabine on terminal colorectal cancer and its influence on high-mobility group box 1 (HMGB1) expression. A total of 86 patients with terminal colorectal cancer were enrolled in this study. Patients received oxaliplatin in combination with gemcitabine. Immunohistochemistry was used to determined the subcellular localization of HMGB1 in cancer tissues as well as in para-carcinoma tissues, and RT-PCR and western blot analysis were used to assess the mRNA and protein expression level, respectively. The total effective rate was analyzed based on WHO tumor chemotherapy reference where complete remission (CR) implies the complete disappearance of the tumor; partial remission (PR) implies that the tumor size was reduced at least by 50%; stable disease (SD) implies that the tumor size remained unchanged and progressive disease (PD) implies an increase in the size of the tumor by ≥25%. We identified 20 cases of CR, 37 cases of PR, 12 cases of SD and 17 cases of PD. The total effective rate (CR+PR) was 66.3%. HMGB1 expression rate in the cancer tissues in the effective group was significantly lower than that in the ineffective group. Positive expression of HMGB1 protein was mainly localized in the karyon. Survival time in the patients with positive HMGB1 expression was significantly shorter than that in the patients with negative HMGB1 expression. In the effective group, HMGB1 mRNA and protein expression levels were obviously lower than those in the ineffective group. We conclude that the reduced expression rate of HMGB1 in terminal colorectal cancer cases was probably related to the effects of oxaliplatin combined with gemcitabine.
Keywords: HMGB1; gemcitabine; high-mobility group box 1; oxaliplatin; terminal colorectal cancer.