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proximal colon cancer

Monday 2 July 2012

Proximal colon cancers; proximal colic adenocarcinoma

The serrated neoplasia pathway is thought to give rise to the majority of sporadic microsatellite instability-high (MSI-H) colon cancer.

Tubular and tubulovillous adenomas with features of the serrated neoplasia pathway have been described, and unlike sessile serrated adenomas, these lesions lack BRAF mutations.

Histological analysis of the precursor adenomas to sporadic MSI-H colon cancer demonstrated a high frequency of crypt serrations compared with MSS colon cancer (93 vs 36%, P < 0.001).

BRAF mutations are found in 76% of sporadic MSI-H and 11% of MSS colon cancers (P < 0.001).

The presence of BRAF mutations in these adenomatous precursors suggests that they represent sessile serrated adenomas with complete cytologic dysplasia.

Patients with sporadic MSI-H colon cancer were more likely to harbour synchronous sessile serrated adenomas (20 vs 8%; P=0.023).

References

- Proximal colon cancers and the serrated pathway: a systematic analysis of precursor histology and BRAF mutation status. Patil DT, Shadrach BL, Rybicki LA, Leach BH, Pai RK. Mod Pathol. 2012 Jun 8. PMID: 22684223