Objective: To investigate the expression of API2-MALT1 fusion gene mRNA in Hashimoto's thyroiditis, thyroid MALT lymphoma and DLBCL, as well as the correlation between the expression and the pathogenesis and prognosis of two types of thyroid lymphoma.
Methods: Eight cases of Hashimoto's thyroiditis, 12 cases of MALT lymphoma and 3 cases of DLBCL in thyroid were selected and retrieved. API2-MALT1 transcripts were investigated in all cases by reverse transcript touchdown-PCR and nested PCR. The effect of API2-MALT1 fusion gene on the prognosis of thyroid lymphomas was assessed by analyzing the clinicopathological features and the follow-up findings.
Results: The variant 1446/1123 transcript was detected in 2 of thyroid lymphomas (1 MALT lymphoma, 1 DLBCL) but not in 8 cases of Hashimoto's thyroiditis and 5 cases of chronic lymphadenitis. Both of API2-MALT1-positive cases were accompanied with Hashimoto's thyroiditis, showing stage I E and no involvement of lymph node.
Conclusion: The incidence of API2-MALT1 transcript in thyroid lymphomas was low; however, the correlation between API2-MALT1 fusion gene and the progression from Hashimoto's thyroiditis to lymphoma could not be excluded; the thyroid lymphoma with API2-MALT1 transcript seemed to develop on a more indolent clinical course.