Regression of low-grade gastric mucosa-associated lymphoid tissue lymphoma after eradication of Helicobacter pylori: possible association with p16 hypermethylation.

BACKGROUND: Many reports have stated that the cure of Helicobacter pylori infection can induce a complete remission of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Although p16 hypermethylation was frequently found in MALT lymphoma, the association between this finding and the remission of MALT lymphoma has not been clarified. We performed a prospective study to evaluate the outcome of patients with low-grade gastric MALT lymphoma and the expression of p16 hypermethylation.

METHODS: We prospectively enrolled 20 patients with H. pylori-positive low-grade gastric MALT lymphoma (stage I E1). After the eradication of H. pylori, the patients were regularly followed-up with endoscopic and histological assessment. The methylation-specific polymerase chain reaction (PCR) (MSP) method was used for the serial detection of p16 hypermethylation.

RESULTS: Eighteen patients (90%) achieved complete remission, with a median duration of 15.7 months. The initial detection rate of p16 hypermethylation was 58% (7 of the 12 patients in whom p16 hypermethylation was evaluated successfully). In a serial investigation, 3 patients who were followed-up for a median 28 months showed that the p16 hypermethylation had disappeared.

CONCLUSIONS: Complete remission of low-grade gastric MALT lymphoma after the eradication of H. pylori infection can be maintained for more than 1 year. Further studies are warranted to investigate the role of p16 hypermethylation in the pathogenesis of gastric MALT lymphoma.