The future in staging of cancer is molecular. Molecular markers will ultimately replace pathologic findings in our staging of gastrointestinal cancer. Corso et al from Italy show that genomic MSI in gastric adenocarcinoma is useful in determining the prognosis of patients. DNA from tumor and from adjacent normal tissue was amplified by pentaplex PCR, and DNA fragments were sequenced, which determined the presence of microsatellites.
DNA microsatellites are small (1-3 bp) repetitive DNA sequences, and instability results from the presence of these, which are absent from normal parental DNA.1 They are the result of mismatch repair gene mutations and have been implicated in hereditary nonpolyposis colorectal cancer2; the present study confirms the utility of MSIs in gastric cancer as well. The authors showed that patients having tumors with all 5 MSI markers did better than those who did not.
Zenilman ME. Correlation of Microsatellite Instability at Multiple Loci With Long-term Survival in Advanced Gastric Carcinoma—Invited Critique. Arch Surg. 2009;144(8):727. doi:10.1001/archsurg.2009.26