Histological and molecular diversity and heterogeneity of precancerous lesions associated with inflammatory bowel diseases

Research output: Contribution to journalArticle

Authors

  • Xianyong Gui
  • Matin Kobel
  • Jose Ferraz
  • Shuhong Liu
  • Young Ou
  • Marco Perrizzolo
  • Robert Winkfein
  • Peter Rambau
  • Douglas Demetrick

Colleges, School and Institutes

External organisations

  • University of Washington School of Medicine
  • University of Calgary

Abstract

Aims: Inflammatory bowel disease (IBD)-associated precancerous lesions may be adenomatous or non-adenomatous with various histomorphologies. We aim to validate the newly proposed classification, to explore the neoplastic nature of the non-adenomatous lesions and to elucidate the molecular mechanisms underlying the different histomorphologies.

Methods: 44 background precursor lesions identified in 53 cases of surgically resected IBD-associated colorectal and ileal carcinomas were reviewed for the histomorphological features (classified into adenomatous, mucinous, sessile serrated adenoma (SSA)-like, traditional serrated adenoma-like, differentiated, eosinophilic and serrated not otherwise specified (NOS)) and analysed for a key panel of colonic cancer-related molecular markers.

Results: Approximately 60% of the lesions were adenomatous, of which some had mixed serrated, mucinous or eosinophilic changes. The remaining non-adenomatous lesions, including all other types except SSA-like type, mostly showed mixed features and focal adenomatous dysplasia. KRAS mutation and p53 mutant-type expression were found in about half cases across all types, while PIK3CA mutation only in some of adenomatous and eosinophilic lesions and MLH1/PMS2 loss in a subset of adenomatous, mucinous and eosinophilic but not in differentiated and serrated lesions. SAT-B2 or PTEN loss and IMP3 overexpression were seen in a small subset of lesions. No BRAF, NRAS or EGFR gene mutation was detected in any type. Certain molecular-morphological correlations were demonstrated; however, no single or combined molecular alteration(s) was specific to any particular morphological type.

Conclusions: IBD-associated precancerous lesions are heterogeneous both histologically and molecularly. True colitis-associated adenomatous lesions are unlikely conventional adenomas. Non-adenomatous lesions without frank cytologic dysplasia should also be regarded as neoplastic.

Details

Original languageEnglish
Pages (from-to)1-12
Number of pages12
JournalJournal of Clinical Pathology
Early online date4 Dec 2019
Publication statusE-pub ahead of print - 4 Dec 2019