Large Colorectal Lesions: Evaluation and Management

Integrated Analysis Identifies Novel Fusion Transcripts in Laterally Spreading Tumors Suggestive of Distinct Etiology Than Colorectal Cancers

BACKGROUND

Laterally spreading tumors (LSTs) of the colon and rectum are a class of abnormality which spreads laterally and appears ulcerated. They are a subclass of colorectal cancer (CRCs) with higher invasive potential than CRCs. Moreover, the etiology of LST still remains obscure.

METHODS

This study aimed to identify unique fusion transcript(s) in LSTs and evaluate their role in LST development and progression. RNA-Seq data for LST samples from the EMBL-EBI database were used to identify fusion transcripts. An integrated approach using Gene Ontology, pathway analysis, hub gene, and co-expression network analysis functionally characterized fusion transcripts to shed light upon the etiology of LSTs.

RESULT

We identified 48 unique fusion genes in LSTs. GO terms were enriched in mRNA metabolic (p ≤ 2.06E-06), mRNA stabilization (p ≤ 1.60E-05), in cytosol (1.20E-05), RBP (p ≤ 2.30E-04), and RNA binding activity (p ≤ 3.51E-08) processes. Pathway analysis revealed an inflammatory phenotype of LSTs suggesting a distinct etiology than CRCs as pathways were enriched in salmonella infection (p ≤ 4.41 e-03), proteoglycans in cancer (p ≤ 1.18 e-02), and insulin signaling (p ≤ 2.13 e-02). Our exclusion and inclusion criteria and hub gene analysis finally identified 9 hub genes. Co-expression analysis of hub genes identified the most significant transcription factors (NELFE, MYC, TAF1, MAX) and kinases (MAPK14, CSNK2A1, CDK1, MAPK1) which were implicated in various cancer pathways. Furthermore, an overall survival analysis of hub genes was performed. Our predefined criterion resulted in the enrichment of NPM1-PTMA (NPM1: p ≤ 0.005) and HIST1H2BO-YBX1 (YBX1: p ≤ 0.02) fusion transcripts, significantly associated with the patient's overall survival.

CONCLUSION

Our systematic analysis resulted in novel fusion genes in LSTs suggesting a different etiology than CRCs. Fusion transcripts were observed more frequently in non-granular LSTs suggestive of genetically more unstable than granular LST. We hypothesize that NPM1-PTMA and HIST1H2BO-YBX1 could be implicated in LST development and progression and may also serve as a prognostic or diagnostic biomarker in future for better management of LSTs.

G-EYE colonoscopy is superior to standard colonoscopy for increasing adenoma detection rate: an international randomized controlled trial (with videos)

BACKGROUND AND AIMS

Colorectal cancer (CRC) is largely preventable with routine screening and surveillance colonoscopy; however, interval cancers arising from precancerous lesions missed by standard colonoscopy still occur. An increased adenoma detection rate (ADR) has been found to be inversely associated with interval cancers. The G-EYE device includes a reusable balloon integrated at the distal tip of a standard colonoscope, which flattens haustral folds, centralizes the colonoscope's optics, and reduces bowel slippage. The insufflated balloon also aims to enhance visualization of the colon during withdrawal, thereby increasing the ADR.

METHODS

In this randomized, controlled, international, multicenter study (11 centers), patients (aged ≥50 years) referred to colonoscopy for screening, surveillance, or changes in bowel habits were randomized to undergo either balloon-assisted colonoscopy by using an insufflated balloon during withdrawal or standard high-definition colonoscopy. The primary endpoint was the ADR.

RESULTS

One thousand patients were enrolled between May 2014 and September 2016 to undergo colonoscopy by experienced endoscopists; 803 were finally analyzed (standard colonoscopy n = 396; balloon-assisted colonoscopy n = 407). Baseline parameters were similar in both groups. Balloon-assisted colonoscopy provided a 48.0% ADR compared with 37.5% in the standard colonoscopy group (28% increase; P = .0027). Additionally, balloon-assisted colonoscopy provided for a significant increase in detection of advanced (P = .0033) flat adenomas (P < .0001) and sessile serrated adenomas/polyps (P = .0026).

CONCLUSION

Balloon-assisted colonoscopy yielded a higher ADR and increased the detection of advanced, flat, and sessile serrated adenomas/polyps when compared with standard colonoscopy. Improved detection by the G-EYE device could impact the quality of CRC screening by reducing miss rates and consequently reducing interval cancer incidence. (Clinical trial registration number: NCT01917513.).