Long non-coding RNA H19 expression in rectal cancer and therapy response

Background & objectives: Long non coding RNA, H19 is an imprinted, maternally expressed gene, usually deregulated in diferent cancer types, including rectal cancer. This study aimed to investigate H19 role as a potential biomarker to predict therapy response in rectal cancer patients. Methods: The study included 14 patients diagnosed with rectal cancer, treated with neoadjuvant chemoradio therapy (nCRT). RNA was isolated by TRIzol reagent from samples of rectal cancer tissue before and after nCRT. Relative expression of H19 was normal- ized to housekeeping GAPDH gene, and expression was analysed by quantitative real-time PCR. Relative expression of H19 was calculated by 2-ΔCt method. Results: Relative expression of H19 was significantly increased in rectal cancer tissue after nCRT (0.244±0.408) compared to the tissue before nCRT (0.043±0.055), p=0.004, Wilcoxon test. According to tumour regression grade (TRG), 85.71% (12/14) of patients did not respond, while 14.28% (2/14) responded to pre- operative CRT. Responders (TRG1, TRG2) and non-responders (TRG3, TRG4) did not differ in H19 expression in tumour tissue before (p=0.659, Mann-Whitney U test) as well as after nCRT (p=0.999, Mann-Whitney U test). Receiver operating curve analy- sis indicates that H19 expression in colorectal tissue before nCRT can not be used as a biomarker for distinguishing responders from non-responders (AUC=0.625, 95%CI=0.257-0.992, p=0.583). Conclusion: Our study suggests H19 upregulation upon neoadju- vant chemoradiotherapy in rectal cancer. The potential predictive value of H19 as a biomarker of therapy response should be studied in a larger group of patients