Medium and large alleles of the PGC gene are risk factors for gastric cancer.

Background: A 100-bp insertion/deletion polymorphism in the pepsinogen C gene has been associated with the risk of gastric cancer (GC).
Objective: We analyzed the relationships of the 100-bp insertion/deletion polymorphism with GC, atrophic gastritis (AG), and intestinal metaplasia (IM) in the Mexican general population (MGP).
Methods: We studied the genomic DNA of subjects with GC n = 80, AG and IM n = 60, controls n = 110, and the MGP n = 97. PGC gene insertion/deletion polymorphism was identified by means of PCR, capillary electrophoresis and GeneScan software.
Results: Different allele sizes of PGC polymorphism were observed in the studied groups, from 266 bp to 499 bp, which were grouped for the analysis as short alleles of 266-399 bp, medium alleles of 400-433 bp and large alleles of 434-499 bp. Carriers of one or two medium alleles, had an increased risk of GC, with OR of 1.99 (CI95% 1.08-3.67 p = 0.026) compared to homozygotes (no medium/no medium).
Conclusions: Previous studies have related PGC short alleles to risk for or protection against GC depending on the ethnic origin of the population. In our study, medium alleles were related to risk for GC. Further studies are required to establish the importance of this polymorphism in the origin of gastric neoplasia.