We assessed the mutational status of the entire KRAS coding sequence in 19 MSI-GC cases by multiplex PCR/sequencing and used peak height ratio determined from electropherograms from KRAS heterozygous mutants and histopathological evaluation to infer tumour heterogeneity in GC.
Among those participants with atrophic gastritis without metaplasia, 19.4% (6 of 25) contained KRAS mutations, indicating that mutation of this important gene is likely an early event in the etiology of gastric carcinoma.
Although KRAS mutations in GC are linked with MSI in the majority of cases, KRAS mutations with MSS status presented with a poor prognosis and a worse outcome.