To identify genes that are associated with progression of malignant lymphoma, the expression profiles of 18 432 genes were analyzed in diffuse large B-cell lymphomas at early (stages I and II, 6 cases) and advanced stages (stages III and IV, 9 cases) by means of cDNA microarrays. By comparing expression profiles between localized and advanced lymphomas, a number of genes that were differentially expressed were identified: 48 genes with increased expression and 30 genes with reduced expression in advanced-stage diffuse large B-cell lymphomas. Increased expression of MPHOSPH1, RUVBL1, CHN2, PSA and CDC10 genes, and reduced expression of COL1A2, COL4A1, FBLN5, CLECSF6, MIC2, CAV1 and S100A10 genes in the advanced lymphoma group were confirmed by semi-quantitative reverse transcription-PCR. RUVBL1 and PSA expression was further confirmed by real-time quantitative PCR, whose results paralleled the microarray data. The highly expressed genes encode proteins that promote cell proliferation and the genes with reduced expression encode adhesion proteins and target protein for cytotoxic T-lymphocytes. These findings suggested that analysis with cDNA microarrays is a useful approach for identifying genes related to tumor progression and their products could be potential tumor markers or diseasespecific targets for anti-tumor therapy.

Death-associated protein (DAP) kinase is a pro-apoptotic serine/ threonine kinase with a death domain, which is involved in apoptosis induced by interferon-γ γ γ γ, tumor necrosis factor-α α α α, and Fas ligand. Down-regulation of DAP kinase gene expression by hypermethylation of its promoter region might result in resistance to apoptotic cell death, and could provide a basis for tumor development. In the present study, we employed methylation-spe- poptosis (programmed cell death) is an important regulatory mechanism for normal development and maintenance of the tissues in multicellular organisms. Several critical genes involved in apoptosis have been identified, such as p53, bcl-2, and Bax. Alterations of these genes have been described in various cancers, and are thought to result in accumulation of cells in which additional genetic changes occur, leading to tumor development.Death-associated protein (DAP) kinase gene is one of the genes which functions as a positive mediator of interferon-γ-induced apoptosis.

SUMMARY:Post-transplantation lymphoproliferative disorder (PT-LPD) is characterized by lymphoid proliferation after organ or bone marrow transplantation. In Western countries, most cases of PT-LPD are B-cell-derived and Epstein-Barr virus-associated, in which alterations of c-myc, p53, and N-ras genes might play a role in disease progression. In Japan, PT-LPD of T-and NK/T-cell types are not uncommon in renal transplant patients. Mutations of p53 (exons 4 through 8), K-ras (exons 1 and 2), c-kit (exons 11 and 17), and ␤-catenin genes (exon 3) in 12 cases of these diseases were analyzed by PCR single strand conformation polymorphism and then by direct sequencing. p53 gene mutations were detected in 5 of 5 cases of peripheral T-cell lymphoma, 3 (60%) of 5 cases of adult T-cell leukemia/lymphoma, and 1 of 2 cases of NK/T cell lymphoma. Twenty-five percent of T and NK/T cell lymphomas showed K-ras mutations. Mutations of c-kit and ␤-catenin genes were found in 33% of cases. Among a total of 42 substitution mutations, 40 were transitions with involvement of CpG sites in 20 to 30% of cases. Most cases had at least one mutation that changed an amino acid, which might have provided the selection pressure for expansion. These findings suggested that p53 gene mutations might play a central role in development of peripheral T-cell lymphoma including adult T-cell leukemia/lymphoma in renal transplant patients. (Lab Invest 2002, 82:257-264).

Pyothorax-associated lymphoma (PAL) is a unique lymphoma developing in the pleural cavity after long-standing pyothorax. They are diffuse large B-cell lymphomas (DLBCLs), frequently with immunoblastic morphology, and show a strong association with Epstein-Barr virus (EBV) infection. In this study, cDNA microarray analysis was performed in six cases with PAL and 12 with nodal DLBCL. Among 5516 informative genes, 348 displayed more than 2-fold difference (higher or lower) of expression level between PAL and nodal DLBCL (P < < < <0.001). These genes are known to be involved in apoptosis, interferon response, and signal transduction. One of the most differentially expressed genes, IFI27 (interferon-α α α α-inducible protein 27) was subjected to quantitative RT-PCR analysis, and increased expression of IFI27 was confirmed. Overexpression of IFI27 was also found in cell lines derived from PAL, but not in other lymphoid cell lines. This study shows that PAL is a distinctive subtype of DLBCL not only in its clinical presentation, but also in its molecular profile. alignant lymphoma develops in the pleural cavity affected by long-standing pyothorax, usually resulted from artificial pneumothorax for the treatment of lung tuberculosis or tuberculous pleuritis.

Pyothorax-associated lymphoma (PAL) is a B-cell lymphoma of mostly large cell type developing in the pleural cavity of patients with long-standing pyothorax. Neuron-specific enolase (NSE) is an enolase comprising γ γ γ γ subunit and is located at high levels in neuronal and neuroendocrine cells, together with their neoplasias. Expression of NSE at protein and mRNA levels was examined in PAL and other types (non-PAL) of non-Hodgkin's lymphomas. In PAL, serum levels of NSE were elevated (5.32 to 168.0, mean 42.6 ng/ml) and tended to decrease after incisional biopsy followed by chemotherapy (2.38 to 195.5, mean 34.1 ng/ml). Two cell lines established from two cases of PAL produced and secreted NSE in the culture medium. Immunohistochemistry revealed that the positive rate for NSE staining in PAL (10 of 14 cases, 71.4%) was significantly higher than that in non-PAL cases (6 of 38 cases, 15.8%) (P < < < <0.01). RT-PCR analysis showed that the expression levels of NSE mRNA in two cell lines and a biopsy sample from PAL were rather similar to those of the control samples from non-neoplastic lymph nodes. These findings suggest the posttranscriptional regulation of NSE in PAL. Thus, an elevation of serum NSE level in patients with chronic pyothorax may be an indicator of PAL development.Key words: Pyothorax-associated lymphoma -Neuron-specific enolase -ImmunohistochemistryQuantitative reverse transcription PCR Enolases are anaerobic glycolytic enzymes catalyzing the interconversion of 2-phosphoglycerate and phosphoenolpyruvate, and are made up of three distinct subunits, α, β, and γ, which form dimers of five types (αα, ββ, γγ, αβ, and αγ).1, 2) Because the γ subunit of enolase is mainly located at high levels in neuronal cells and neuroendocrine cells as αγ and γγ forms, they are designated as neuronspecific enolases (NSE).3) Since NSE is also present in neurogenic and neuroendocrine tumors, such as small cell carcinoma of lung and neuroblastoma, 4) measurement of its serum concentration is useful for the diagnosis and follow-up of these tumors. Though the serum concentration of NSE is seldom assayed in patients with malignant lymphoma, there are reports of the elevation of serum concentration of NSE in 17 to 21% of cases with non-Hodgkin's lymphoma (NHL). 5,6) Pyothorax-associated lymphoma (PAL) is a B-cell lymphoma developing in the pleural cavity of patients with over 20 years' history of chronic pyothorax resulting from artificial pneumothorax for the treatment of pulmonary tuberculosis or tuberculous pleuritis. 7,8) PAL is one of the Epstein-Barr virus (EBV)-associated lymphomas, and expresses latent genes of EBV including latent membrane proteins and EB nuclear antigens.9, 10) The common presenting symptoms of PAL include pain in the chest, back, or shoulder, and respiratory symptoms such as productive cough, often with hemoptysis, fever or dyspnea. Roentgenographic examinations show mass shadows involving the lung in over 30% of PAL patients. These findings might suggest a diagnosis of lung cancer, especially sma...