[High incidence of t (11; 18)/API2-MALT1 and BCL10 aberrant nuclear expression in pulmonary mucosa-associated lymphoid tissue lymphomas].

Objective: To detect the BCL10 expression and chromosomal translocations in pulmonary mucosa-associated lymphoid tissue (MALT) lymphomas, including t (11; 18)/API2-MALT1; t (1; 14)/IgH-BCL10 and t (14; 18)/MALT1-IgH, and to determine if aberrant nuclear BCL10 expression is related with chromosomal translocations.
Methods: Twenty-three cases of pulmonary MALT lymphomas were collected from Cancer Hospital of Fudan University. BCL10 was detected by immunohistochemistry of EnVision method, and API2-MALT1, BCL10, MALT1, IgH chromosomal abnormalities were detected by fluorescent in situ hybridization (FISH) technique.
Results: BCL10 was expressed in 82.6% (19/23) of the pulmonary MALT lymphomas. Among those cases, 9 of 23 (39.1%) were expressed in the cytoplasm, and 10 of 23 (43.5%) were in the nucleus. In the FISH results, 9 cases (39.1%, 9/23) showed API2-MALT1 fusion gene, 1 case with possible BCL10-IgH abnormality, but none showed chromosomal abnormalities related with MALT1 and IgH gene simultaneously. Among 10 BCL10 nuclear expressive cases only 5 harbored genetic abnormalities. There was no correlation between BCL10 aberrant nuclear expression and chromosomal translocations (chi(2) = 0.306, P = 0.685). Follow-up of 10 cases for a period of 7 to 35 months showed that all the patients were alive. Because different treatments applied in different patients (chemotherapy only, surgery with chemotherapy or surgery only), best available treatment could not be confirmed in this study.
Conclusions: t (11; 18)/API2-MALT1 was the most common chromosomal abnormality in pulmonary MALT lymphomas, but t (1; 14)/BCL10-IgH and t (14; 18)/MALT1-IgH were rare. Pulmonary MALT lymphomas also had higher nuclear BCL10 expression, which was not correlated with chromosomal abnormalities. As a result, BCL10 nuclear expression and cytogenetic aberration may be helpful in the diagnosis, especially for small biopsy specimens.