APC gene deletions in gastric adenocarcinomas in a Chinese population: a correlation with tumour progression

The adenomatous polyposis coli (APC) gene encodes a tumor suppressor protein that acts as an antagonist of the Wnt signaling pathway. It has been shown to be involved in genetic instability and to be down-regulated in several human carcinomas. The chromosome locus of APC, 5q21-22, is frequently deleted in gastric cancers (GCs). The functional impact of such regions needs to be extensively investigated in large amount of clinical samples. Case-matched tissues of GC and adjacent normal epithelium (n=141) were included in this study. Quantitative PCR was carried out to examine the copy number as well as mRNA expression of APC gene in gastric malignancies. Our results showed that copy number deletions of APC were present in a relatively high percentage (25.9%, 34 out of 131) of gastric cancer samples. There was a correlation between APC deletion and tumor progression (p < 0.01) as well as gene expression (p < 0.05) in collected GC samples. On the other hand, mRNA levels of APC were also impaired in GC samples with unaltered copy numbers. Sporadic GCs exhibit different mechanisms of APC regulation.