Abstract: Objective:To investigate the relationship between MALT1 mRNA expression in extranodal B cell lymphoma and the pathogenesis of MALToma and DLBCL, and to explore the effect of MALT 1 mRNA expression on the clinicopatho-logic features and survival of lymphoma patients. Methods:H&E and immunohistochemical staining were applied to ob-serve the expression of Bcl-2 and Ki-67in 106 samples of extranodal B cell lymphoma. The mRNA of MALT1 was detected by RT-PCR. Clinicopathological data were reviewed. Follow-up and statistical analysis were performed. Results:Expression of MALT 1 mRNA was statistically different between the cases with lymph node metastasis and those without lymph node mestastasis, and between stagingⅠ-  cases and stage Ⅲ- Ⅳcases, The expression of MALT1 mRNA in cases with posi-tive expression of MALToma, DLBCL, and Bcl- 2 was higher than in those without expression of the three indices (P<0.05). However, no significant difference was found in MALT1 mRNA expression between cases with Ki-67≥30% and those with Ki-67<30% (P>0.05). MALT 1 mRNA-positive cases showed a worse survival status than MALT 1 mRNA-negative cases (P< 0.05). Conclusion: Expression of MALT1 gene is different between MALToma and DLBCL. Inhibition of apoptosis by Bcl- 2 overexpression caused by activation of NF-κ B may lead to the pathogenesis of MALToma and DLBCL. The expression of MALT1 mRNA is associated with the types of lymphoma, involvement of lymph node, stage of lymphoma, and patient sur -vival. The expression of MALT1 gene may be associated with poor prognosis of MALToma and DLBCL.