Deciphering Elevated Microsatellite Alterations at Selected Tetra/Pentanucleotide Repeats, Microsatellite Instability, and Loss of Heterozygosity in Colorectal Cancers.

Journal Article (Journal Article)

Elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) are common in colorectal cancers (CRCs). The association between EMAST and classic mono/dinucleotide microsatellite instability (MSI) is unknown. We assessed the stability of 13 tetranucleotide and three pentanucleotide repeat markers in tumor and normal tissue from 22 MSI-high and 107 microsatellite-stable CRC samples. When present, instability was observed at tetra/pentanucleotide repeats and was defined as elevated microsatellite alterations at selected tetra/pentanucleotide repeats-high (EMASTP-H; ≥30% instability), -low (EMASTP-L; <30% instability), or -stable (EMASTP-S). EMASTP instability, including high and low, was observed in 50 of 123 CRCs (41%), including all MSI-high tumors and 28 of 101 microsatellite-stable tumors (28%). MSI-high CRCs were more likely to be EMASTP-H compared with microsatellite-stable tumors with EMASTP instability. Tetranucleotide markers VWA and D13S317 were the two most frequently altered loci. Loss of heterozygosity was more common in EMASTP-L/S than in EMASTP-H CRCs. Frequencies of loss of heterozygosity at three loci were different between EMASTP-L and EMASTP-S tumors. In addition, right-sided tumor site, large tumor size, high tumor grade, and the presence of Crohn-like reaction were significantly associated with EMASTP-H CRCs. However, there were no differences in clinicopathologic features between EMASTP-L and EMASTP-S tumors. In summary, more CRCs exhibited genomic instability as EMASTP than as MSI. EMASTP instability may prove to be an important prognostic/therapeutic indicator in CRCs.

Full Text

Duke Authors

Cited Authors

  • Wang, Y; Vnencak-Jones, CL; Cates, JM; Shi, C

Published Date

  • May 2018

Published In

Volume / Issue

  • 20 / 3

Start / End Page

  • 366 - 372

PubMed ID

  • 29474982

Pubmed Central ID

  • PMC5966712

Electronic International Standard Serial Number (EISSN)

  • 1943-7811

Digital Object Identifier (DOI)

  • 10.1016/j.jmoldx.2018.02.001


  • eng

Conference Location

  • United States