# CV‐SCAN (Crystal Violet Staining for Colitis‐Associated Neoplasia): A Novel Endoscopic Staining Method to Detect Paneth Cell Metaplasia and Ulcerative Colitis (UC)‐Associated Neoplasia in UC

## TL;DR

CV-SCAN is a new endoscopic method that detects Paneth cell metaplasia and cancer risk in ulcerative colitis patients using crystal violet staining.

## Contribution

CV-SCAN is a novel endoscopic staining technique for detecting Paneth cell metaplasia and UC-associated neoplasia in ulcerative colitis.

## Key findings

- CV-SCAN achieved 81.3% sensitivity and 84.9% specificity for detecting Paneth cell metaplasia.
- Stained areas showed upregulated Paneth cell-specific and UCAN-associated genes.
- CV-SCAN enables direct visualization of precancerous changes for risk stratification in UC patients.

## Abstract

Paneth cell metaplasia (PCM), a metaplastic change associated with chronic inflammation in ulcerative colitis (UC), may be linked to UC‐associated neoplasia (UCAN). However, no endoscopic method currently exists for detecting PCM. This study aimed to develop and validate a novel endoscopic staining technique—CV‐SCAN—for identifying PCM and UCAN, and to explore the molecular characteristics of the stained areas.

This retrospective observational study included 131 patients with UC undergoing surveillance colonoscopy. CV‐SCAN involved spraying an ultra‐diluted solution (0.006%) of crystal violet from the descending colon to the rectum. Biopsies were obtained from stained and non‐stained areas and evaluated histologically and molecularly. RNA expression profiles were analyzed via microarray and real‐time RT‐PCR. The diagnostic performance of CV‐SCAN for detecting PCM was assessed, along with its correlation with UCAN history.

CV‐SCAN visualized sharply demarcated, purple‐stained areas corresponding to PCM or UCAN. PCM was significantly associated with a history of UCAN. Uniform, dark staining was characteristic of PCM, while UCAN showed heterogeneous staining with small round pits. CV‐SCAN achieved a sensitivity of 81.3% and a specificity of 84.9% for PCM detection. Molecular analysis revealed upregulation of Paneth cell–specific (DEFA5, DEFA6), small intestinal (CCL25, APOC3), and UCAN‐associated (IL17RC) genes, along with downregulation of SATB2 in stained areas.

CV‐SCAN is a novel and effective endoscopic staining method for detecting PCM and UCAN in patients with UC. It enables risk stratification through direct visualization of precancerous changes and may facilitate early detection and targeted surveillance.