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We report a follicular lymphoma (FL) case presenting the coexistence of two tumor cell subpopulations in lymph node (LN) and bone marrow (BM), which exhibited an inverse pattern of immunoglobulin light (IgL) chain gene rearrangement and expression: Igκ−λ+ in LN and Igκ+λ− in BM. These tumor clones shared an identical BCL2-IgH recombination, accompanying t(14;18)(q32;q21) translocation, and an identical variable, diversity and joining segments joining with clone-specific VH somatic hypermutations on the untranslocated IgH allele. Our study provides further evidence that FL clones, originating from common progenitor cells, can be developed independently at different sites and with different IgL expression after immune selection. [ABSTRACT FROM AUTHOR]

Abstract: The BCL6 gene is frequently disrupted at its 5′ noncoding region by 3q27 chromosomal translocations in B-cell lymphoma. As a result of translocation, BCL6 is juxtaposed to reciprocal partners, such as the immunoglobulin (Ig) gene family. Besides the Ig loci, multiple non-Ig partners of the BCL6 translocation have been reported. Here we describe the identification of the GAS5 (growth arrest-specific transcript 5) gene as a novel partner of the BCL6 in a patient with diffuse large B-cell lymphoma, harboring the t(1;3)(q25;q27). In this case, the chromosome 1 breakpoint was located within the intronic small nucleolar RNA (snoRNA) sequence of GAS5 and the chromosome 3 breakpoint at 4 kb upstream of BCL6 exon 1a. As the result of chromosomal translocation, the GAS5–BCL6 chimeric transcripts were expressed, in which the 5′-terminal oligopyrimidine (5′TOP) sequence of GAS5 was fused to the whole coding sequence of BCL6. The GAS5 gene on chromosome 1q25 is the second BCL6 partner, to the SNHG5 on 6q15, which is classified as a non-protein-coding multiple snoRNA host and 5′-TOP class gene. [Copyright &y& Elsevier]

Abstract: Primary rectal MALT lymphoma is rare comprising less than 1% of MALT lymphomas. A 26-year-old man was referred to our hospital because of constipation and abdominal fullness. Colonoscopy revealed multiple submucosal tumors in rectum. Histopathological examination showed dense proliferation of small lymphoid cells, but lymphoepithelial lesions were not observed. The cells were CD5(−), CD10(−), CD20(+) and cyclinD1(−). The patient was diagnosed as having MALT lymphoma. The patient was negative for API2-MALT1 gene, and radiotherapy was performed and CR was achieved. With the accumulation of cases, establishment of a treatment strategy for primary rectal MALT lymphoma is expected in the future. [Copyright &y& Elsevier]