Role of SATB1 in neoadjuvant radiotherapy of rectal cancer

Abstract

Objective To investigate the role of special AT-rich sequence binding protein 1 (SATB1) in neoadjuvant radiotherapy of rectal cancer. Methods SATB1 expression was immunohistochemically determined in primary cancer, normal mucosa, biopsy and lymph node metastasis from 142 rectal cancer patients who underwent preoperative radiotherapy (RT), 68 with and 74 without RT before surgery. The expression of SATB1 in rectal cancer tissues (n=142) and normal mucosa tissues (n=107), preoperative biopsy cancer tissues (n=84), and metastatic lymph nodes (n=43) were detected by tissue microarray. To investigate the effect of SATB1 expression on the prognosis of patients with rectal cancer. The relationship between SATB1 expression and multiple radiotherapy-related factors was analyzed by bioinformatics methods. Results SATB1 increased from normal mucosa to primary cancer (χ2=5.396, P=0.032), whereas it decreased from primary cancer to lymph node metastasis (χ2=6.405, P=0.022) in non-RT patients. Strong SATB1 was independently related to worse overall survival (HR, 0.516; P=0.039; 95% CI: 0.274~0.969) and disease-free survival (HR, 0.558; P=0.025; 95% CI: 0.335~0.930) in RT but not non-RT patients. Radiation can decrease SATB1 expression of rectal cancer tissues. SATB1 was negatively related to ataxia-telangiectasia mutated (ATM) and pRb2/p130 (χ2=5.427, P=0.032 and χ2=4.610, P=0.047), and positively to Ki-67 and TEM1 expression (χ2=4.339, P=0.037 and χ2=7.376, P=0.014) in patients underwent surgery after preoperative RT, which were verified in bioinformatics analysis. Conclusions Radiation can decrease SATB1 expression, and SATB1 may confer survival benefit for rectal cancer patients with preoperative RT by involving in radiation-responsive signaling pathways. Key words: Rectal neoplasms; SATB1; Preoperative radiotherapy; Prognosis; Bioinformatics