Published online Feb 28, 2016. doi: 10.3748/wjg.v22.i8.2460
Peer-review started: September 25, 2015
First decision: October 14, 2015
Revised: November 6, 2015
Accepted: December 30, 2015
Article in press: December 30, 2015
Published online: February 28, 2016
Processing time: 155 Days and 20.3 Hours
Currently, gastric cancer (GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the pro-carcinogenic activity of important genes. These factors include genetic susceptibility expressed in a single-nucleotide polymorphism, various acquired mutations (chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances (e.g., Helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma (EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesis are modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.
Core tip: There are numerous factors that may trigger gastric carcinogenesis. They include genetic susceptibility, acquired mutations and favourable environmental circumstances, which combine and multiply within the lifetime. Therefore, the incidence of gastric cancer is the highest among the elderly. Conversely, young patients are exposed to environmental carcinogens for a short period, so they are a reliable subgroup in which to study primary genetic alterations. This review provides a summary of the data published thus far concerning the molecular characteristics of gastric cancer and highlights the outstanding features of early-onset gastric cancer.