Aberrant SOX2 expression in colorectal cancers does not correlate with mucinous differentiation and gastric mucin MUC5AC expression

Virchows Arch. 2014 Oct;465(4):395-400. doi: 10.1007/s00428-014-1638-y. Epub 2014 Aug 10.

Abstract

Colorectal cancer (CRC) can be divided into non-mucinous and mucinous subtypes, of which the latter portends to have a worse clinical prognosis. A previous study suggested a putative link between SOX2 expression observed selectively in mucinous CRC and the induction of the gastric mucin MUC5AC. In this study, we re-evaluated the expression behavior of SOX2, MUC5AC, and CDX2 in both types of CRC. We performed immunohistochemical analysis on 90 cases of non-mucinous CRCs, 57 cases of mucinous CRCs, and 15 case-matched normal intestinal mucosa. In contrast to the previously suggested link between SOX2 and mucinous CRC, we observe aberrant expression of SOX2 at equal levels in both subtypes. Fluorescence in situ hybridization (FISH) analysis shows that expression is not attributed to genomic amplification. While SOX2 and CDX2 are normally expressed in a reciprocal manner, SOX2-positive tumor cells co-express CDX2. Furthermore, we show that MUC5AC is expressed independently of SOX2. In conclusion, we show that aberrant SOX2 expression is specifically linked neither to mucinous CRCs nor to the induction of MUC5AC, in contrast to previous suggestions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / metabolism
  • Adenocarcinoma / pathology*
  • CDX2 Transcription Factor
  • Cell Differentiation*
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology*
  • Gastric Mucins / metabolism
  • Homeodomain Proteins / biosynthesis
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Mucin 5AC / biosynthesis*
  • SOXB1 Transcription Factors / biosynthesis*

Substances

  • CDX2 Transcription Factor
  • CDX2 protein, human
  • Gastric Mucins
  • Homeodomain Proteins
  • MUC5AC protein, human
  • Mucin 5AC
  • SOX2 protein, human
  • SOXB1 Transcription Factors