Association of inducible nitric oxide synthetase genotype and Helicobacter pylori infection gastric cancer risk may be due to faulty primer design.

Rafiei et al recently described an association between the presence of the C150T polymorphism of the inducible nitric oxide synthase (iNOS) gene and Helicobacter pylori (H. pylori) induced gastric cancer. When we used primer-BLAST to find the polymerase chain reaction (PCR) product that would be generated by the primers used by these authors no products against any of the sequences present in the GenBank database were found. Further analysis of the iNOS sequences present in the GenBank suggest that the result from their study might come from a faulty primer design and may thus represent an artifact. Alternatively they may be correct and have identified a truly interesting explanation for the mechanism whereby H. pylori induces gastric cancer but some additional experiments would be in order to exclude the possibility of a PCR artifact.