SPECIFICITY OF POLYMERASE-CHAIN-REACTION MONOCLONALITY FOR DIAGNOSIS OF GASTRIC MUCOSA-ASSOCIATED LYMPHOID-TISSUE (MALT) LYMPHOMA - DIRECT COMPARISON TO SOUTHERN BLOT GENE REARRANGEMENT

The specificity of polymerase chain reaction monoclonality in the diag nosis of gastric lymphoma was prospectively evaluated, Gastric mucosal tissue from normal gastric mucosa (N = 13), benign gastric ulcers (N = 3), chronic Helicobacter pylori gastritis (N = 3), gastric mucosa-as sociated lymphoid tissue (N = 16), and gastric lymphoma (N = 15) was o btained. Polymerase chain reaction amplification of the heavy-chain fr amework 2A gene was performed, The sensitivity and specificity of heav y-chain clonality, in the detection of gastric lymphoma, were 73.3% an d 45.7%, respectively. Determination of monoclonality by polymerase ch ain reaction methodology is not an acceptable technique for confirming the diagnosis of gastric lymphoma as it is too sensitive, detecting m inute populations of clonal lymphocytes that occur in benign diseases as well as larger populations of clonal lymphocytes associated with ma lignant gastric lymphoproliferative diseases, Southern blot gene rearr angement testing should be utilized to determine clonality in the eval uation of gastric lymphocytic infiltrates.