RESUMO
<p><b>OBJECTIVE</b>To investigate promoter methylation status of LITAF gene in B-cell lymphoma and to explore transcription regulation of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on LITAF gene.</p><p><b>METHODS</b>One hundred and five paraffin specimens including 54 cases of diffuse large B cell lymphoma (DLBCL), 15 small lymphocytic lymphoma (SLL), 8 mucosa-associated lymphoid tissue lymphoma (MALT) and 6 follicular lymphoma (FL) were included. Five reactive lymphoid hyperplasia samples were collected as control. Methylation status of CpG island in LITAF gene in the specimens and in Raji, Pfeiffer and Daudi cell lines were detected by methylation-specific PCR (MSP). LITAF expression in Raji, Pfeiffer and Daudi cell lines with or without 5-Aza-CdR treatment was detected by Western blot and immunohistochemistry. The inhibitory ratio in the three cell lines was measured by MTT assay.</p><p><b>RESULTS</b>The frequency of LITAF gene methylation in B-cell lymphoma was 89.5% (94/105) . Among them, 3.8% (4/105) showed complete hypermethylation. In control group, however, there was no methylation in CpG island of LITAF gene promoter. The expression of LITAF was recovered or increased along with the cell growth inhibition when the cells exposed to demethylating reagent.</p><p><b>CONCLUSIONS</b>LITAF gene silencing with aberrant CpG methylation is probably one of the critical events to the oncogenesis of B-cell lymphoma, which may have important implications as a candidate marker for diagnosis and target gene therapy.</p>