学术会议
background: the microsatellite instability-high (msi-h) phenotype confers good prognosis and greater response to immunotherapy in colorectal cancer(crc). the mutational landscape of msi-h crc is unclear. this study was designed to illustrate the difference mutation profile between the msi-h and microsatellite stable (mss) crc.
methods: tumor tissue and matched blood samples from 40 patients with colorectal cancer were collected. microsatellite instability (msi) status were detected by pcr-amplified for five mononucleotide repeat markers (bat-25, bat-26, nr-21, nr-24 and mono-27). mutation profiles were sequenced by a cancer gene-targeted ngs panel.
results: the tumor mutation burden(tmb) of the msi-h crc patients was significantly higher than those mss crc patients. compared with the mss crc, msi-h crc involved more genes and pathways. furthermore, we found the copy number variation (cnv) was different between the two groups. the copy number instability (cni) score of msi-h crc patients was significantly lower than those mss crc patients. msi-h crc patients showed a higher frequency of tp53 gene cnv gain compared with mss crc (41% (7/17) in msi-h crc versus 13% (3/23) in mss crc).
conclusions: the mutational landscape are different between the msi-h and mss colorectal cancer. compared with mss colorectal cancer, the msi-h colorectal cancer patients have higher tumor mutation burden(tmb) and lower copy number instability (cni) score. keywords: colorectal cancer, microsatellite instability, tumor mutation burden, copy number instability. abbreviations crc, colorectal cancer; tmb, tumor mutation burden; msi-h, the microsatellite instability-high; mss, microsatellite stable; cnv, copy number variation.