[Detection of API2-MALT1 fusion gene transcript and its diagnostic value in pulmonary MALT lymphoma].

OBJECTIVE

To investigate the feasibility of detecting API2-MALT1 fusion gene transcript in paraffin-embedded tissue and its diagnostic value for pulmonary MALT lymphoma.

METHODS

Ten archival cases of pulmonary MALT lymphoma were selected and reviewed. Five archival cases of chronic lymphadenitis were used as negative control. Detection of the API2-MALT1 fusion transcript was performed by RT-PCR followed by second-round PCR using nested primers. beta-actin mRNA assay was utilized as an internal control in all samples.

RESULT: beta-actin was detected in all samples (100%). The API2-MALT1 fusion transcript was found in 3 of 10 pulmonary MALT lymphomas (30%) and in none of the 5 chronic lymphadenitis cases. The pulmonary lesions in the fusion gene positive cases were all single tumors of less than 5.0 cm in diameter and limited to either the right or left of the lung.

CONCLUSION

Detection of API2-MALT1 fusion transcript in paraffin-embedded tissues is feasible by nested RT-PCR and is of diagnostic value. The presence of API2-MALT1 fusion gene may be correlated with a subset of pulmonary MALT lymphomas that have limited lung involvement.