Lymphomas with follicular and monocytoid B-cell components. Evidence for a common clonal origin from follicle center cells

We investigated the clonal relationship between follicular center cell and monocytoid B-cell components of non-Hodgkin lymphoma by isolating the components and comparing the nucleotide sequences of the complementarity-determining region (CDR)3 of the rearranged immunoglobulin heavy chain (IgH) gene. Paraffin blocks from 4 cases with amplifiable DNA using the polymerase chain reaction (PCR) were identified. Multiple representative cell clusters of the 2 components were obtained by microdissection, and the IgH CDR3 was amplified using a seminested PCR. Most of the PCR products obtained from both tumor components in each case had identical lengths when analyzed with polyacrylamide gel electrophoresis (PAGE) and identical migratory patterns on denaturing gradient gel electrophoresis (DGGE). These findings indicate sequence identity of the IgH CDR3 of both tumor components. Sequence analysis showed that point mutations were responsible for bands from the same case that had nonidentical migratory patterns by DGGE. The components in each of the 4 cases studied have the same clonal origin. Intraclonal sequence variations in the IgH gene were observed in 2 cases, consistent with the presence of continued somatic hypermutation after establishment of the clone. The expression of CD10 and bcl-2, as well as the detection of bcl-2 rearrangements in 2 cases, indicate that these lymphomas are of follicular center cell origin.

The clonal relationship between nodular sclerosis Hodgkin's disease with a clonal Reed-Sternberg cell population and a subsequent B-cell small noncleaved cell lymphoma

We evaluated the clonal relationship between a case of nodular sclerosis Hodgkin's disease (NSHD) and a small noncleaved cell (SNC) lymphoma that subsequently developed. Single Hodgkin and Reed-Sternberg (H-RS) cells were isolated from immunostained sections of the NSHD by micromanipulation, and the immunoglobulin heavy chain gene (IgH) complementarity determining region (CDR) III of the cells was amplified by the polymerase chain reaction (PCR). A clonal population of H-RS cells was found in the NSHD tumor. The nucleotide sequence of the clonal H-RS cells was compared with the clonal IgH CDRIII sequence from the SNC lymphoma. The two sequences were found to be unrelated. In addition, clone-specific primers and probes were designed from the two clonal IgH CDRIII sequences and used to investigate the presence of the respective clonal population in the NSHD tumor. The latter studies confirmed the presence of a major clonal H-RS cell population, as detected by the single cell assay, but cells corresponding to the SNC clone were not demonstrable by this highly sensitive technique. These findings suggest that the SNC arising in this case represents the development of the second neoplasm clonally unrelated to the preceding NSHD. They also support the recent findings that the H-RS cells in classical HD consist of a clonal population of B cells.

c-myc amplification in hepatocellular carcinoma predicts unfavorable prognosis

Structural alterations and amplifications of the c-myc oncogene have been implicated in the pathogenesis and progression of several human neoplastic diseases. To study the role of c-myc amplification in human hepatocellular carcinomas (HCC), we analyzed 20 HCC using differential polymerase chain reaction (PCR). DNA used for differential PCR was extracted from formalin-fixed, paraffin-embedded tissue obtained by radiographically directed needle aspiration biopsy. Differential PCR reactions included sets of primers for c-myc and a control gene, dopamine D2 receptor (D2R), which yielded products of 150 bp and 110 bp, respectively. Evaluation of amplification was based on the relative concentration of c-myc and D2R PCR products. The c-myc amplification was detected in 10 of 20 HCC. Cases with c-myc amplification tended to have higher histologic grade and were significantly (P = 0.05) associated with worse prognosis. Amplification was present in none of two Grade 1 tumors, seven of the fourteen Grade 2 tumors, and three of four Grade 3 tumors. The mean survival times (+/- SEM) for patients with and without c-myc amplification were 5.7 (+/- 1.8) and 13.8 (+/- 2.6) months, respectively. These results indicate that c-myc amplification in HCC can be evaluated by differential PCR of needle biopsy specimens, and is an unfavorable prognostic indicator.

The presence of Enterocytozoon bieneusi spores in the lamina propria of small bowel biopsies with no evidence of disseminated microsporidiosis. Enteric Opportunistic Infections Working Group

Enterocytozoon bieneusi is the most frequently reported microsporidial infection of humans. In patients with the acquired immunodeficiency syndrome, Enterocytozoon infects the lining epithelial cells of the small intestine, hepatobiliary tract, and gallbladder. Because Enterocytozoon has been thought to be limited to infecting lining epithelial cells, the mechanism of spread of E bieneusi within the intestine, to the biliary tract, and, in two case reports, to distant organs remains unknown. This report describes a patient with acquired immunodeficiency syndrome and intestinal microsporidiosis due to E bieneusi. Histopathologic examination of well-oriented biopsies from the duodenum and jejunum revealed both intra- and extracellular spores of Enterocytozoon extending deeply into the lamina propria, where they were located adjacent to capillaries. The patient has not developed disseminated disease 20 months after the initial diagnosis. In this patient, the demonstration of E bieneusi spores in extraepithelial tissues does not appear to be associated with development of subsequent systemic infection.