Clinical characteristics and prognostic significance of TCGA and ACRG classification in gastric cancer among the Chinese population

Abstract

Molecular classifications of gastric cancer (GC) by the Asian Cancer Research Group (ACRG) and The Cancer Genome Atlas Consortium (TCGA) are useful for diagnosis and treatment of GC. However, their clinical significance is unknown. The present study aims to explore the associations between subtypes of GC and prognosis of patients with GC. Immunohistochemistry (IHC) was used in the ACRG molecular classification of GC, while next-generation sequencing technology was used in TCGA molecular classification. The results indicated that, out of a total of 65 cases of GC, some were classified as Epstein-Barr virus positive type (9.2%, 6 of 65), some as microsatellite instability (MSI) type (23.1%, 15 of 65), some as gene stable type (21.5%, 14 of 65) and some as chromosome instability type (46.2%, 30 of 65) according to TCGA typing standard. Of the total 65 GC cases, some were classified as MSI (21.5%, 14 of 65), some as microsatellite stable/epithelial-mesenchymal transition (MSS/eMT; 20.0%, 13 of 65), some as MSS/tumor protein 53 active (TP53+; 15.4%, 10 of 65) and some as MSS/TP53 inactive (43.1%, 28 of 65) according to ACRG typing standard. ARCG molecular subtype (P=0.010) and Lauren classification (P=0.011) were independently correlated with the overall survival of patients with GC. In conclusion, TCGA classification based on a Chinese population is the same as TCGA typing based on a European population in terms of proportion and clinical characteristics, but there are differences in gene amplification and gene mutation. ACRG molecular classification could be performed by IHC analysis and may be a valuable independent prognostic marker for patients with GC.