Involvement of non-Helicobacter pylori helicobacter infections in Helicobacter pylori-negative gastric MALT lymphoma pathogenesis and efficacy of eradication therapy

Eradication therapy is known to be effective against Helicobacter pylori-positive gastric MALT lymphoma but predicting the efficacy of eradication therapy against Helicobacter pylori-negative gastric MALT lymphoma is difficult. Recent reports have shown that non-Helicobacter pylori helicobacter infections induce gastric MALT lymphoma, and we aimed to clarify whether non-Helicobacter pylori helicobacter infections are associated with the efficacy of eradication therapy. We analyzed eradication therapy as a first-line treatment for 182 cases of gastric MALT lymphoma, classified according to Helicobacter pylori infection and API2-MALT1 mutation status. We also evaluated the non-Helicobacter pylori helicobacter infection status in 29 Helicobacter pylori-negative cases via PCR with DNA extracted from paraffin-embedded biopsy tissues. Finally, we analyzed the relationship between non-Helicobacter pylori helicobacter infection status and eradication therapy outcome. The API2-MALT1 mutation was observed in 13/182 patients (7.1%), none of whom were cured by eradication therapy. Helicobacter pylori-negative cases had a significantly higher non-Helicobacter pylori helicobacter infection rate than Helicobacter pylori-positive cases (16/29, 55% vs. 3/29, 10%; P