c-MYC Amplification in Mucinous Gastric Carcinoma: A Possible Genetic Alteration Leading to Deeply Invasive Tumors

Background: Patients with mucinous gastric carcinoma (MGC) usually have a poor prognosis, largely due to the advanced stage of disease. In this study, we evaluated the effects of c-MYC amplification on tumor stage and disease-specific survival of 128 patients with MGC and compared the results with those of 302 patients with non-mucinous gastric carcinoma (non-MGC). Patients and Methods: Two-color fluorescence in situ hybridization (FISH) for c-MYC was performed on 430 GC samples. Real-time quantitative polymerase chain reaction (q-PCR) analysis for c-MYC was also performed after tumor microdissection. Results: c-MYC amplification was found in 10.2% of MGCs and 6.0% of non-MGCs. c-MYC amplification was more frequently found in MGCs of higher tumor stage than in MGCs of lower stage (p=0.038). c-MYC amplification in MGC was correlated with greater invasion depth (p=0.007). The mean survival time of patients with c-MYC amplification was shorter than that of patients without c-MYC amplification in MGC. Real-time q-PCR results showed that the calculated c-MYC/GAPDH ratios were higher in c-MYC-amplified MGC than in c-MYC-non-amplified MGC. Conclusion: This study showed that c-MYC amplification in MGC is highly correlated with advanced stage and deeply invasive MGC. This suggests that c-MYC amplification in MGC could be a possible genetic alteration contributing to the frequent presentation of advanced-stage MGC.