Aberrant p53 in benign colon biopsies flagged later dysplasia in PSC-IBD

Design

Retrospective case-control immunohistochemistry study

Population

25 PSC-IBD patients before dysplasia vs 20 IBD controls without neoplasia

Primary outcome

Aberrant p53 overexpression in prior benign biopsies

Effect

36% vs 5% of patients (p = 0.027); sensitivity 36%, specificity 95%

Patients with primary sclerosing cholangitis and inflammatory bowel disease develop dysplasia that is often flat, non-conventional and right-sided, and hard to see at colonoscopy. A Histopathology study, published in June 2026, stained 91 benign surveillance biopsies from 25 PSC-IBD patients taken at the colonoscopy before dysplasia was found (mean 20 months earlier), and 76 biopsies from 20 IBD controls who never developed neoplasia.

Aberrant p53 overexpression — strong nuclear staining in at least 10% of epithelial cells — was seen in 36% of patients who went on to dysplasia against 5% of controls (p = 0.027), mostly in the right colon. As a predictor it was specific (95%) but insensitive (36%). Combining p53 with DNA flow cytometry raised sensitivity to 64% with specificity 90%.

This is a small case-control study, not a validated surveillance test. It does suggest that strong, patchy p53 in a 'negative' right-colon biopsy from a PSC-IBD patient deserves a comment in the report and closer endoscopic follow-up.

• Aberrant p53 in benign PSC-IBD biopsies was highly specific but missed most patients who later developed dysplasia.
• Consider adding a comment when strong patchy or diffuse p53 is seen in an otherwise benign PSC-IBD biopsy.
• Most aberrant staining was in the right colon, matching where non-conventional dysplasia tends to arise.
• A negative p53 stain does not lower risk meaningfully, given the low sensitivity.
• p53 is not a validated surveillance test; endoscopic surveillance intervals should follow current guidance.

Why it matters

A stain on tissue already being taken could pick out PSC-IBD patients heading for invisible dysplasia before it is seen.

Don't overread it

With 25 cases and 20 controls, these accuracy figures are preliminary and the predictive values depend on the case-control design.

The statistics, in plain English

Specificity of 95% means few false alarms; sensitivity of 36% means about two in three future dysplasia patients had no aberrant p53. Predictive values from a case-control study overstate how the test would perform in routine surveillance, where dysplasia is rarer.

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