Expression of CARD11 (CARMA1) and efficacy of non-surgical treatment in gastric MALT lymphoma

点击翻译按钮获取中文摘要

While caspase recruitment domain (CARD)-membrane-associated guanylate kinase (MAGUK) protein 1 (CARMA1/CARD11) and CARD9 play important roles in lymphocyte activation, the significance of CARMA1 and CARD9 in the pathogenesis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma still remains to be elucidated. In the current research, we investigated the expression of mRNA of CARMA1, CARD9, BCL10 and the API2-MALT1 chimeric transcript in tissue specimens from 65 cases of primary gastric B-cell lymphoma (43 cases of low-grade MALT lymphoma, 16 MALT lymphoma plus diffuse large B-cell lymphoma [DLBCL] and 6 DLBCL without MALT lymphoma) and 18 cases of chronic gastritis, using the reverse transcription-polymerase chain reaction. The expressions of CARMA1 and BCL10 proteins were also examined immunohistochemically in 30 cases of lymphoma. As a result, CARMA1 mRNA was detected in 55% of the lymphoma cases, but in only 17% of the chronic gastritis cases. The positive rates of CARD9,BCL10 and API2-MALT1 chimeric transcript in the lymphoma cases were 48%,98%, and 8%, respectively, while these three molecules were not detected in any cases with chronic gastritis. The expression of CARMA1 and CARD9 was frequent in the H.pylori negative cases (100% and 86%), in the API2-MALT1 chimeric transcript positive cases (100% and 100%), and in the cases not responding to H.pylori eradication (76% and 71%). In addition, the CARMA1 expression was more frequently positive in DLBCL without MALT lymphoma (100%) than in MALT lymphomas (51%). CARMA1 protein expression significantly correlated to the expression of CARMA1 mRNA and also to nuclear BCL10 expression. In conclusion, overexpression of CARMA1 and CARD9 is presumed to be associated with the development or progression of gastric B-cell lymphoma, especially for those cases in which H.pylori is unrelated to the pathogenesis.