Increasing serum miR-124-3p expression is associated with the high survival rate of a rectal cancer patient after neoadjuvant chemoradiotherapy

Background: Colorectal cancer is the world’s third most prevalent cancer, which 30% of cases are rectal cancer. Today, the effective diagnostic marker to accurately predict clinical outcome patients response to therapy did not found yet. Several research studies have indicated that miRNA potential as a prognostic biomarker. MiR-1243p plays as tumor suppressor that significantly down-regulated in some cancer and could radiosensitize human colorectal cancer cells. The aim of the study is to investigate the expression of miR-124-3p from rectal cancer patient who receive nCRT, and analyze its association with patient survival and others clinical parameters. Methods: This research involved 15 patients with histologically confirmed locally advanced rectal cancer (LARC) and received neoadjuvant chemotherapy/nCRT (radiotherapy 45-50 Gy with 1,8-2 Gy fractions over 1 to 3 months and chemotherapy 5-fluorouracil was administered orally). Patient blood (5 ml) were collected from peripheral venous before and after neoadjuvant chemoradiotherapy. miR-124-3p expression was performed using qRT-PCR and calculate using Livak method. Results: In this study, we found that increasing of miR-124 was significantly associate with high survival of rectal cancer patient (P = 0,003; OR =30, 95% CI = 1,41 – 638,15). Average of miR-124-3p expression increase significantly after nCRT (P<0,041, fold change before=1,14 ± 1,25; after=2,4 ± 1,84). Conclusion: Our finding suggests that miR-124-3p expression in blood serum was potential as biomarkers to predict rectal cancer patient survival after neoajduvant chemoradiotherapy. (Health Science Journal of Indonesia 2019;10(2):90-5)