Thymic Extranodal Marginal Zone Lymphoma of Mucosa-associated Lymphoid Tissue: A Gene Methylation Study.

Thymic Extranodal Marginal Zone Lymphoma of Mucosa-associated Lymphoid Tissue: A Gene Methylation Study.

Jan 2013

Takino H, Li C, Yamada S, Sato F, Masaki A, Fujiyoshi Y, Hattori H, Inagaki H.

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 MALTlymphomas 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.

Informa

MALT Lymphomas.

2003

**Editors Note: While this study dates back to 2003, it is still worth the reading for the information contained.**

Malek SN, Hatfield AJ, Flinn IW.

Source

The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, 1650 Orleans Street, CRB Room 388, Baltimore, MD 21231, USA.

Abstract

Mucosa-associated lymphoid tissue (MALT) lymphomas occur in a variety of organs, including the orbit, conjunctiva, salivary glands, skin, thyroid gland, lungs, stomach, and intestine. These tumors are often localized and of indolent clinical behavior. Diagnosis is made by pathologic evaluation of a tissue biopsy. Careful staging is mandatory and tailored to the initial presentation. Staging includes a history and physical, chemistries, computed tomography scan, and bone marrow biopsy. 

This information is supplemented with an ear, nose, and throat consultation, esophagogastro-duodenoscopy, colonoscopy, endoscopic ultrasound of the stomach, and cytogenetic/immunohistochemical analysis of the tumors. Treatment is tailored to organ involvement and stage at presentation. Eradication of Helicobacter pylori using a triple anti-H. pylori regimen approved by the US Food and Drug Administration is standard therapy for all H. pylori-positive gastric MALT lymphomas. Endoscopic ultrasound- and computed tomography-staged gastric MALT stage IE tumors will achieve a complete response with this approach in approximately 60% to 90% of patients (the more superficial the tumor, the better the response). Patients with tumors that are T4 node-positive Musshoff stage IIE1 and IIE2 or tumors with adverse cytogenetics should receive radiotherapy or surgery with or without radiotherapy. Tumors with a significant high-grade component or large cell tumors with a minor low-grade MALT component should receive CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-based chemotherapy. Localized MALT lymphomas of the orbit, conjunctiva, salivary glands, and thyroid gland are treated successfully with radiotherapy. Surgery as first-line therapy for gastric MALT lymphomas was replaced by attempts at organ preservation. In the past, margin-free surgical excision or tumor debulking followed by radiation therapy and chemotherapy has been highly effective for gastric MALT lymphomas. 

Therefore, surgical excision of large cell or bulky tumors of the stomach, thyroid, lung, and salivary gland, followed by adjuvant radiotherapy or chemotherapy, may still be an important consideration in selected patients. Surgery still has a role for patients with relapsed or refractory low-grade disease and life-threatening hemorrhage. Disseminated MALT lymphomas are incurable and are treated primarily with chemotherapy according to symptoms.

PubMed

A Case of Synchronous Lung Adenocarcinoma and Extranodal Marginal Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) Type.

July 2012

Jung CY, Kwon KY.

Source

Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea.

Abstract

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type (extranodal MZL) is a distinct subgroup of non-Hodgkin's lymphoma. Pulmonary extranodal MZL is a rare entity and accounts for less than 0.5% of primary pulmonary malignancies. Only a few cases of simultaneous occurrence of lung cancer and pulmonary extranodal MZL have been reported. A 60-year-old woman was referred to our hospital with a pulmonary nodule. She was diagnosed with lung adenocarcinoma by percutaneous needle biopsy. The protrusions into the left main bronchus were found by accident while performing bronchoscopy during lung cancer evaluation. The bronchial lesions were diagnosed as extranodal MZL. Although the patient underwent surgical resection for the lung adenocarcinoma, the pulmonary extranodal MZL was left untreated; it was monitored during follow-up visits. To our knowledge, this is the first report of synchronous lung adenocarcinoma and primary extranodal MZL of the main bronchus.

NIH

Eradication Therapy Is Effective for Helicobacter pylori-Negative Gastric Mucosa-Associated Lymphoid Tissue Lymphoma.

2012

Asano N, Iijima K, Terai S, Jin X, Ara N, Chiba T, Fushiya J, Koike T, Imatani A, Shimosegawa T.

Source

Division of Gastroenterology, Tohoku University Graduate School of Medicine.

Abstract

Mucosa-associated lymphoid tissue (MALT) lymphomas are extra-nodal B-cell lymphomas arising from MALT, and the most commonly affected organ is the stomach. Helicobacter pylori (H. pylori) eradication therapy with proton-pump inhibitors and antibiotics is the first-line therapy for H. pylori-positive gastric MALT lymphomas, but the effectiveness of the therapy for H. pylori-negative gastric MALT lymphomas remains controversial. Hence, we aimed to evaluate the effectiveness of this eradication therapy for H. pylori-negative MALT lymphomas. The H. pylori infection status of 158 gastric MALT lymphomapatients followed in our unit was judged by urea breath test, rapid urease test, histology of the biopsy specimen taken from the stomach during endocopy, and serum antibody against H. pylori. Seventeen patients that were negative for all four tests and did not have gastric mucosal atrophy were treated with antibiotic eradication therapy. The average age at diagnosis was 56.8 years old (range: 36-73 years), and the median follow-up period after H. pylori eradication in all 17 patients was 5.3 years (range: 0.3-12.7 years). Five patients (29.4%) achieved complete remission (CR) by eradication therapy alone. Comparison between the responding and non-responding patients revealed that the patients endoscopically diagnosed to have a single lesion of gastric MALT lymphoma were seen only in the responding group, whereas all non-responding patients had multiple lesions (P < 0.05). In conclusion, H. pylori eradication therapy achieved a favorable CR rate in H. pylori-negative gastric MALT lymphoma patients and could be considered as a first-line therapy, especially for patients with a single lesion.

PubMed