Expression of granulocyte colony-stimulating factor receptor in rectal cancer

Abstract

To evaluate whether granulocyte colony-stimulating factor receptor (G-CSFR) expression before preoperative irradiation can predict the radiosensitivity of rectal cancer. The expression of G-CSFR was examined, using immunohistochemistry, in biopsy specimens from 126 patients with locally advanced rectal adenocarcinoma before preoperative irradiation. Radiosensitivity was then evaluated according to the Rectal Cancer Regression Grading. Endoscopic inspection was used to detect the tumor area in each patient. General patient information, such as age, gender, lymph node status, tumor size and degree of differentiation was recorded. A statistical analysis was then performed to evaluate the correlation between clinical or pathological parameters and G-CSFR expression in tumors. According to endoscopic inspection, the tumor area ranged from 4 to 48 cm² (median, 15 cm²). Positive G-CSFR immunoreactions (G-CSFR⁺) were observed in 85 specimens, and negative (G-CSFR⁻) in 41. No significant differences were found in age, gender, tumor invasion, lymph node status and tumor size between G-CSFR⁺ and G-CSFR⁻ patients. G-CSFR expression was positively correlated with poor radiotherapy response (58.8% vs 75.6%, P = 0.014, r = 0.219). The proportion of well-differentiated tumors in G-CSFR⁺ and G-CSFR⁻ patients was 24.7% and 36.6%, respectively. Sphincter preservation was observed in 57.6% of G-CSFR⁺ patients and 78.5% of G-CSFR⁻ patients. Significant correlations were found between G-CSFR expression and tumor differentiation (24.7% vs 36.6%, P = 0.019, r = 0.210), as well as sphincter preservation (57.6% vs 78.5%, P = 0.044, r = 0.180). The expression of G-CSFR before preoperative irradiation may predict the radiosensitivity of rectal cancer.