Published online Sep 14, 2014. doi: 10.3748/wjg.v20.i34.12346
Revised: March 26, 2014
Accepted: May 23, 2014
Published online: September 14, 2014
MicroRNAs have been increasingly recognized as useful biomarkers for colorectal cancers (CRC). We have recently observed that microRNA-31 (miR-31) expression is associated with BRAF mutation and prognosis in CRC. Moreover, high miR-31 expression is frequently detected in sessile serrated adenomas compared with hyperplastic polyps (HPs). These results suggest that miR-31 may contribute to the progression of serrated lesions. At a follow-up colonoscopy, we observed the case of a 75-year-old man with a 7-mm flat-elevated lesion in the cecum and diagnosed the lesion as an early invasive carcinoma with serrated features. Tissue specimens were obtained from the representative areas to compare the molecular alterations in the carcinoma component with those in the HP component. Higher miR-31 expression was observed in the carcinoma component (57-fold increase) and the HP component (8-fold increase) compared with the paired normal mucosa, suggesting that miR-31 may be one of the key molecules in serrated pathway progression.
Core tip: At a follow-up colonoscopy, we observed the case of a 75-year-old man with a 7-mm flat-elevated lesion in the cecum. Because the flat-elevated area displayed serrated features, we diagnosed the lesion as an early invasive carcinoma with a hyperplastic polyp (HP) component. Higher microRNA-31 (miR-31) expression was observed in the carcinoma component (57-fold increase) and the HP component (8-fold increase) compared with the paired normal mucosa. This is the first case report of early invasive colorectal cancer with an HP component in which miR-31 expression was analyzed. Our results suggest that miR-31 may be an important molecule in serrated pathway progression.