The treatment of choice for locally advanced rectal cancer is preoperative chemoradiotherapy (CRT). Despite around half of patients do not respond, suffer unnecessary toxicities and surgery delays, there are no biomarkers to guide preoperative CRT outcome. MicroRNA-31 (miR-31) has been related to acquisition of 5-fluorouracil resistance in rectal cancer however its potential predictive value of response to preoperative CRT in locally advanced rectal cancer remains unknown.
Eight-two patients diagnosed with locally advanced rectal cancer who were preoperatively treated with 5-fluorouracil based CRT were selected for this study. The miR-31 expression was quantified in formalin-fixed paraffin-embedded biopsies from this cohort previous to CRT therapy administration and the results obtained were correlated with clinical and molecular characteristics, pathological response and outcome.
Overexpression of miR-31 was found in 34.2% of the cases. Its overexpression significantly predicted poor pathological response (p = 0.018) and worse overall survival (OS) (p = 0.008). Multivariate analysis confirmed the clinical significance of miR-31 in determining pathological response to neoadjuvant CRT as well as OS.
miR-31 quantification emerges as a novel valuable clinical tool to predict both pathological response and outcome in locally advanced rectal cancer patients.
Clinical trial identification
Legal entity responsible for the study
Fundación Jimenez Diaz
All authors have declared no conflicts of interest.