PLoS ONE (Jan 2015)

EMAST is associated with a poor prognosis in microsatellite instable metastatic colorectal cancer.

  • Sabine Venderbosch,
  • Shannon van Lent-van Vliet,
  • Anton F J de Haan,
  • Marjolijn J Ligtenberg,
  • Monique Goossens,
  • Cornelis J A Punt,
  • Miriam Koopman,
  • Iris D Nagtegaal

DOI
https://doi.org/10.1371/journal.pone.0124538
Journal volume & issue
Vol. 10, no. 4
p. e0124538

Abstract

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PurposeTo determine the frequency and prognostic value of elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) in metastatic colorectal cancer (mCRC) patients in relation to microsatellite instability (MSI) status and MSH3 protein expression.Material and methodsThe frequency of EMAST was evaluated in mCRC patients with MSI tumors and microsatellite stable (MSS) tumors. A literature overview was performed to compare the frequency of EMAST in our study with existing data. Immunohistochemistry for MSH3 was compared with EMAST status. Outcome was studied in terms of overall survival (OS) of mCRC patients with MSI and MSS tumors.ResultsEMAST was evaluated in 89 patients with MSI tumors (including 39 patients with Lynch syndrome) and 94 patients with MSS tumors. EMAST was observed in 45.9% (84 out of 183) of patients, with an increased frequency in MSI tumors (79.8% versus 13.8%, p ConclusionFrequency of EMAST was increased in mCRC patients with MSI tumors, compared to MSS tumors. Our data suggest that the presence of EMAST correlates with worse OS in these patients. There was no effect of EMAST on the prognosis of patients with MSS tumors. A limitation of our study is the small number of patients in our subgroup analysis.