MicroRNA signatures of colonic adenomas according to histology

Adenomatous polyps adjacent to colorectal cancer (CRC) were found to exhibit two distinct microRNAs (miRs) patterns from normal mucosa to low- and separately, to high-grade dysplasia; presence in screen-detected adenoma of non-cancer patients is unknown. Global miR expression was performed on biopsies obtained from 109 healthy patients undergoing screening/surveillance colonoscopy. Included were normal mucosa (NM); hyperplastic polyp (HP); tubular adenoma (TA), tubulovillous adenoma, with or without, high-grade dysplasia (TVHG) and serrated-polyps; sessile serrated adenoma (SSA) and traditional serrated adenoma (TSA). Logistic regression was used to model miRs predictive of histology and CRC risk. We identified 99 miRs that differed across five histologic groups (FDR=0.05) and that accurately separated on histology (Concordance Index (CI)=0.96). In HPNM, miRs-145, -143, -107a, -23b, and -24 were upregulated whereas miRs-663, -1268, -320b, -1275, and -671 where overexpressed in TVHGs (FDR P<0 .05). The expression of miR-145 and -30a showed high accuracy to separate low from high-risk polyps independent of serrated status (CI= 97.1%; AUC 93.4%). For TSAs, miR-125b and -199a were uniquely downregulated relative to HPNMs and miR-335 discriminated between non-serrated and serrated histology. Histologically advanced polyps from non-cancer patients share miR alterations with those reported for CRC and high-grade adenoma adjacent to tumor including downregulation of immune regulatory miRs-125 and -199a in TSAs; polyp that frequently present with in situ carcinoma. These data extend evidence that miR patterns of high-risk adenoma are detectable in subset of screen-detected adenoma for which measurement may be useful in in adenoma risk stratification. The statistical analysis included 113 samples allocated to one of five pathology groups. Samples desginated as normal mucosa and hyperplastic polyp (HPNM) were combined to serve as the controls. The remaining four pathologic groups included tubular adenoma (TA), tululovillous adenoma with or without high grade dysplasia (TVHG), sessile serrated adenoma (SSA), and traditional serrated adenoma (TSA). The RNA was isolated from FFPE biopsy tissues obained from 109 human patients undergoing colonoscopy. Therefore, study design included 113 human RNA samples with biological replicates for five conditions.