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Although t(11;18)(q21;q21), t(1;14)(p22;q32), and a few other genetic mutations are specific markers for the Helicobacter pylori (HP)-independent status of gastric mucosa-associated lymphoid tissue (MALT) lymphoma, the molecular mechanisms responsible for HP-independence of gastric MALT lymphoma without such translocations and mutations remain uncharacterized. In the present study, we describe the establishment and characterization of a novel MALT lymphoma cell line, MA-1, which was derived from a gastric MALT lymphoma which was negative for both t(11;18)(q21;q21) and t(1;14)(p22;q32); the patient had failed HP eradication therapy and chemotherapy. The cell morphology and the immunophenotype of this cell line were similar to that of the original gastric MALT lymphoma. Comparative genomic hybridization analysis showed no significant gene copy number changes. Spectral karyotyping displayed a near-diploid chromosome content (482nXY), with at least 13 chromosome structural abnormalities. Furthermore, fluorescence in situ hybridization analyses disclosed the existence of three sub-clones, characterized by t(14;18)(q32;q21)/IGH-BCL2, t(14;18)(q32;q21)/IGH-MALT1, and the presence of both chromosomal translocations in the same cell, respectively; whereas amplification of the genes CRAD9, TRAF2, and BCL10 were not found. In conclusion, we have established the first human gastric MALT lymphoma cell line, which is characterized by unusual and complex chromosome translocations and will be useful to explore further the molecular mechanisms of HP-independence in gastric MALT lymphoma.

Clinical presentations of end-stage renal disease (ESRD) patients on dialysis with upper urinary tract urothelial carcinoma (UUT-UC) are different from those with normal renal function. The pathogenesis remains unknown. We investigated the pathogenetic influence of chromosomal aberrations in patient on dialysis with UUT-UC. The chromosomal aberrations of UUT-UC specimens from seven dialysis patients were assessed by conventional comparative genomic hybridization (cCGH). Subsequently, we further investigated 20 cases by whole genome and fine-tiling oligonucleotide array-based CGH to demonstrate gains and losses, and compared with the clinicopathologic background. The chromosomal aberrations in UUT-UC specimens from dialysis patients were more complex than in bladder urothelial carcinoma (B-UC). Our data showed that gains at 5p, 7, 19q, and losses at 4q, 9p, and 15q are common in UUT-UC of ESRD patients. Gains in regions associated with DNA repair genes were noted in this study. High-stage and high-grade tumors displayed more copy number variants. In addition, female ESRD patients with UUT-UC had more frequent chromosomal aberrations than their male counterparts. In conclusion, unique chromosomal aberrations were indentified in UUT-UC in ESRD patients.