Expression of the leucinerich repeat containing G protein-coupled receptor 5 in locally advanced rectal cancer in response to neoadjuvant chemoradiotherapy

Abstract

Objective To investigate changes in expression of the tumor stem cell marker Leucinerich repeat containing G protein-coupled receptor 5 (Lgr5) before and after neoadjuvant chemoradiotherapy and its predictive effect on neoadjuvant chemoradiotherapy. Methods A retrospective analysis was performed on the clinical data of 42 patients with locally mid-low advanced rectal cancer, who underwent neoadjuvant chemoradiotherapy followed by total mesorectal excision (TME) radical surgery. The patients were all given the test of Lgr5 level prior to and after the new adjuvant therapy. Results The univariate analysis showed that pre-chemoradiotherapy T stage (cT1-3) (P<0.05), pre-chemoradiotherapy N stage (P<0.05), pathological complete response (pCR) after neoadjuvant chemoradiotherapy (P<0.01) were associated with Lgr5 level before neoadjuvant chemoradiotherapy for locally mid-low advanced rectal cancer. In 42 patients, 11 (21.4%) achieved pCR after neoadjuvant chemoradiotherapy. The relationship between Lgr5 levels and pCR were assessed. The expression of Lgr5 protein was higher in the tissues with deeper infiltration or lymph node metastasis. The expression of Lgr5 protein before and after neoadjuvant chemoradiotherapy was 73.80% and 28.57% respectively. Conclusion The expression of Lgr5 is significantly correlated with invasion and lymph node metastasis, and may play an important role in the occurrence and development of epithelial rectal carcinoma. The expression of Lgr5 is related to the degree of tumor pathological remission after neoadjuvant chemoradiotherapy. Overexpression of Lgr5 provides an important implication of malignancy and prognosis in the local mid-low advanced rectal cancer. Key words: Leucinerich repeat containing G protein-coupled receptor 5; Neoadjuvant chemoradiotherapy; Rectal cancer