Characterization of chromosomal aberrations in thymic MALT lymphoma
Department of Pathology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.Pathology International (Impact Factor: 1.69). 02/2012; 62(2):93-8. DOI: 10.1111/j.1440-1827.2011.02764.x
Mucosa-associated lymphoid tissue (MALT) lymphoma arising in the thymus is a rare disorder that shows a strong association with autoimmune disease. Several MALT-lymphoma-specific and -associated chromosomal abnormalities, including t(11;18), t(14;18), t(1;14), trisomy 3 and trisomy 18, are known to occur. The former translocation results in apoptosis inhibitor 2 gene (API2)-MALT lymphoma-associated translocation 1 (MALT1) fusion. In this study, we examined 14 cases of thymic MALT lymphomas for API2-MALT1 fusion using multiplex reverse transcription polymerase chain reaction and looked for trisomy 3, trisomy 18 and abnormalities of MALT1 and IGH genes using fluorescence in situ hybridization. Thymic MALT lymphoma cases had a high frequency of trisomy 3 (7/14 cases), a very low incidence of trisomy 18 (1/14) and no detectable MALT1-associated (0/13) or IGH-associated (0/13) gene abnormalities including t(11;18). A review of the literature showed that the pattern of chromosomal aberrations in thymic MALT lymphoma was similar to those of thyroid and salivary gland MALT lymphomas. Although frequently detected, trisomy 3 was not associated with any of the clinicopathological factors analyzed, suggesting that trisomy 3 may play a role in lymphoma development. In conclusion, the present study showed that thymic MALT lymphoma has a characteristic pattern of chromosomal aberrations that may be similar to those of other autoimmune-associated MALT lymphomas.
- [Show abstract] [Hide abstract]
ABSTRACT: Abstract Although rare, thymic mucosa-associated lymphoid tissue (MALT) lymphoma is considered to be a distinct clinicopathological entity. Using a methylation-specific polymerase chain reaction, we analyzed thymic MALT lymphomas (n=18) for their methylation of the following seven tumor suppressor genes: DAPK1, p16(INK4A), p14(ARF), CDH1, RARB, TIMP3, and MGMT. Reactive lymph nodes (n=16) were used as a control. Of the seven genes examined, thymic MALT lymphomas had an increased number of genes that were methylated (2.9 genes) as compared with reactive lymph nodes (0.63, p=0.0003). In particular, thymic MALT lymphomas showed a frequent methylation of DAPK1, CDH1, TIMP3, and p14(ARF). In addition, gene methylation of the p14(ARF) was associated with a larger tumor size while that of the other three genes was not associated with any clinicopathological features examined. This study suggests that methylation of tumor suppressor genes may play an important role in thymic MALT lymphoma.
- [Show abstract] [Hide abstract]
ABSTRACT: The patient was a 72-year-old female with the chief complaint of abdominal fullness. A giant primary myoma of the uterine cervix was suspected, and total hysterectomy was performed. Based on a postoperative histopathological examination of the tumor a diagnosis of diffuse large B-cell lymphoma (DLBCL) was made in the uterus and a mass in the greater omentum was diagnosed as a marginal zone B-cell lymphoma (MZBCL). No flow-cytometry studies or chromosome or gene examinations were performed on a fresh specimen. The results of an examination of a paraffin block histopathology specimen by fluorescence in-situ hybridization (FISH) showed no mucosa associated lymphoid tissue lymphoma translocation gene 1 (MALT1) (18q21.1), B-cell lymphoma 2 (BCL2) (18q21.3), or BCL6 (3q27) split signals in either the uterus or the greater omentum, however, trisomy 18 was detected in approximately 50%-70% of the tumor cells in both the uterus and the greater omentum. Trisomy 18 was present in around 15-33% of the DLBCL cells and MZBCL cells. These findings suggested a strong possibility that the tumor cells in the uterus and greater omentum were the same clone and that transformation from MZBCL to DLBCL had occurred. Since DLBCLs that result from a transformation usually have a worse outcome than de novo DLBCLs, even when a DLBCL seems to have originated in the uterus the surrounding tissue should always be examined, and caution should be exercised in regard to transformation from a low-grade B-cell lymphoma to a DLBCL.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.