Promoter Methylation Status of Multidrug Resistance 1 (MDR1) Gene in Noncancerous Gastric Mucosa Correlates WithHelicobacter PyloriInfection and Gastric Cancer Occurrence

We investigated the methylation status of multidrug resistance 1 (MDR1) gene promoter in noncancerous gastric mucosa in relation to gastric cancer (GC) occurrence. Methylation of the MDR1 promoter was estimated in 127 GC and 82 non-GC patients. A significant association was found between higher methylation ratio and occurrence of GC. Higher methylation ratio was also associated with occurrence of GC in both Helicobacter pylori-positive and Helicobacter pylori-negative subjects. Higher MR was also associated with Helicobacter pylori infection. Methylation status of MDR1 gene in noncancerous gastric mucosa would be useful for predicting GC occurrence.