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PubMed1991

Primary cutaneous B-cell lymphoma: a unique type of low-grade lymphoma. Clinicopathologic and immunologic study of 83 cases.

The clinical presentation and course, and the morphoimmunologic features of primary cutaneous B-cell lymphoma (CBCL) were investigated in a series of 83 patients. Fifty-one patients were male and 32 were female (male-to-female ratio of 1.6:1); CBCL primarily involved the elderly (median age, 58 years). A locoregional extension of the disease was quite frequent (86.7%). The neoplastic cells showed a range of appearances reminiscent of the whole spectrum of follicular/parafollicular cells. The antigenic phenotype of tumor cells (CD19+, CD20+, CD22+, CD28+, CD10-, CD5-, MB2+, CD74+/-, CDw75+/-, MT2+/-, surface immunoglobulin + monoclonal/-) plus the presence of admixed CD14- dendritic reticulum cells suggest a mantle-zone nature for CBCL. The nonaggressive clinical behavior with a substantial tendency to remain localized to a limited area of the skin, the quite good response to nonaggressive treatment, and the dichotomy existing between the enhancement of morphoimmunologic atypism--which parallels the increasing age and growth rate of lesions--and the constant benign overall prognosis on long-term follow-up make CBCL a unique type of lymphoma of low-grade malignancy. Proper recognition of CBCL is mandatory to avoid possible undertreatment or overtreatment of the patients affected.

Adult↗
PubMed2006

Outcomes in patients with splenic marginal zone lymphoma and marginal zone lymphoma treated with rituximab with or without chemotherapy or chemotherapy alone.

BACKGROUND: The optimal management of patients with splenic marginal zone lymphoma/marginal zone lymphoma (SMZL) is controversial. The objective of this retrospective study was to compare the outcomes of patients with SMZL who received treatment with rituximab, rituximab plus chemotherapy, or chemotherapy alone. METHODS: The Leukemia Service database was searched for patients with splenic lymphoma who were registered between May 1995 and October 2004. The indications for treatment were the same as those used for patients with chronic lymphocytic leukemia. RESULTS: SMZL was confirmed in 70 patients. The median age was 64 years. The median number of CD20 molecules per cell was 69 x 10(3). Forty-three patients required systemic therapy; rituximab in 26 patients, chemotherapy plus rituximab in 6 patients, and chemotherapy alone in 11 patients. Ten additional patients underwent splenectomy, and 17 patients were in the observation group. The overall response rates were 88% with rituximab, 83% with rituximab plus chemotherapy, and 55% with chemotherapy alone; the 3-year survival rates were 95%, 100%, and 55%, respectively. The 3-year failure-free survival (FFS) rates were 86%, 100%, and 45% in the rituximab, rituximab plus chemotherapy, and chemotherapy alone groups, respectively. Rituximab treatments resulted in longer survival and FFS compared with chemotherapy. Rituximab alone resulted in disappearance of splenomegaly in 92% of patients and normalization of absolute lymphocyte counts. In univariate analysis, younger age and rituximab-based therapy were predictive of longer FFS. CONCLUSIONS: Rituximab with or without chemotherapy was found to have major activity in patients with SMZL. These results may be associated with high levels of cellular CD20 antigen sites. Rituximab should be the treatment of choice, at least in older patients with SMZL who have comorbid diseases.

Adult↗
PubMed1986

Lymphoma models for B cell activation and tolerance. IV. Growth inhibition by anti-Ig of CH31 and CH33 B lymphoma cells.

CH31 and CH33 are B cell lymphomas whose growth in vitro is inhibited by anti-Ig reagents, including both polyclonal and monoclonal anti-mu antibodies, and an anti-idiotype antiserum. Antibodies against class I or class II major histocompatibility complex antigens do not affect the growth of these cells. Inhibition is dependent on surface Ig cross-linking and does not require ligand binding to Fc receptors. Interestingly, the inhibition of growth by anti-mu is reversed in CH31 (but not CH33) by E. coli lipopolysaccharide. These lymphomas should provide excellent models to study the mechanisms of growth inhibition mediated by surface Ig cross-linking and the pathways of its reversal.

Animals↗
PubMed1988

Antibody targeting to the murine lymphoma ESb-MP: increased accumulation due to reduced internalization into lymphoma cells as compared to normal lymphoid cells.

Using rat monoclonal antibody (MAb) 12-15A against the spontaneously metastasizing mouse lymphoma variant ESb-MP, we elaborated conditions for targeting. In vitro, high binding of labelled antibody to ESb-MP cells and low binding to lymphoid cells (e.g., spleen cells) was noted. In vivo, we observed pronounced accumulation in spleen, lymph nodes and bone marrow, the uptake kinetics indicating high accessibility of the target antigen in these tissues, and rapid clearance of radioactivity from blood and most normal tissues, indicating degradation of the antibody and excretion of the label. Binding to lymphoma tissue was slow but persistent, resulting in high tumor:tissue ratios only after 2-3 days. Biodistribution could be dramatically changed by pre-treatment of animals with excess cold antibody, which reduced trapping of labelled antibody in normal lymphatic tissue, leading to prolonged persistence in the blood and preferential uptake into tumor tissue. Monovalent 12-15A fragments showed less pronounced binding to lymphatic tissue, while being rapidly cleared from the circulation by virtue of their inherent tendency to bind to kidney tissue. Tumor:tissue ratios up to 56:1 were obtained by a combination of pre-treatment with unlabelled 12-15A IgG or Fab fragment, followed by injection of labelled fragment or IgG, respectively. This is interpreted on the basis of differences in the internalization and retention of antigen-antibody complexes. Pre-treatment obviously leads to a temporary blockade or removal of the target antigen, which is much more efficient with normal lymphoid cells than with tumor cells. Thus, it may become possible to target antibodies into the tumor despite concurrent antigen expression on normal tissue.

Animals↗
PubMed1989

Relationship between tumorigenicity and the dosage of lymphoma- vs. normal-parent-derived chromosome 15 in somatic cell hybrids between lymphoma cells with rearranged pvt-1 gene and normal cells.

Somatic cell hybrids were generated between YACUT, a doubly drug-resistant subline of YAC-1 (a Moloney-virus-induced T-cell lymphoma of strain A/Sn origin with 2 proviral insertions near the pvt-1 locus) and normal diploid fibroblasts of CBAT6T6 origin. Three independent fusions were performed. Three uncloned hybrid cultures and 9 independently-derived clones were tested for tumorigenicity by the inoculation of graded cell numbers into syngeneic hosts. One of 3 uncloned hybrid cultures and 3 of 9 clones were weakly tumorigenic (take incidence 0%), and 1 of 3 uncloned hybrid cultures and 6 clones were highly tumorigenic (take incidence greater than 80%). One weakly tumorigenic hybrid and 3 weakly tumorigenic clones carried 3 copies of the tumor-derived chromosome 15 and 2 copies of the normal fibroblast-derived t(14;15) chromosomes. In contrast, 2 highly malignant hybrid clones lost one copy of the normal-fibroblast-derived t(14;15), but contained increased numbers (3.44-4.44) of the tumor-derived chromosome 15. Four tumorigenic segregants selected from the weakly tumorigenic fibroblast hybrids by in vivo inoculation showed the same cytogenetic change as the highly tumorigenic hybrid clones, in that the ratio of the normal:tumor-derived chromosomes 15 changed from 1.18-1.55 to 4.11-5.71. Tumorigenicity was thus associated with a modified balance between the tumor vs. the normal-parent-derived 15-chromosomes. Instead of the usual 3:2 ratio, the tumor-derived 15-chromosomes increased disproportionately, whereas the relative number of the normal-parent-derived 15-chromosome decreased, as a rule. These results suggest that amplification of the lymphoma-derived chromosome 15 favors tumorigenicity, but that this effect is counteracted by some influence emanating from the normal-parent-derived homologous chromosome.

Animals↗
PubMed2006

A marginal zone phenotype in follicular lymphoma with t(14;18) is associated with secondary cytogenetic aberrations typical of marginal zone lymphoma.

Marginal zone differentiation of follicular lymphomas (FL), sometimes referred to as monocytoid B-cell differentiation, is a relatively uncommon phenomenon. Recently, this type of differentiation was also linked to secondary cytogenetic aberrations of chromosome 3 in a small number of patients. We have analysed 131 primary nodal FL with t(14;18)(q32;q21) for secondary cytogenetic aberrations previously described as recurrent in marginal zone lymphomas (MZL) to identify their frequency and possible association with morphological evidence of marginal zone differentiation. We searched for trisomy of chromosomes 3, 12, and 18, gains of chromosome arm 3q, deletions of chromosome arm 7p, structural anomalies with break-points in 1q21 and 1p34, as well as the t(1;2)(p22;p12), t(1;14)(p22;q32), t(3;14)(q27;q32), t(6;14)(p21;q32), and t(11;18)(q21;q21) translocations. At least focal morphological evidence of marginal zone differentiation occurred in 35/131 (27%) FL with t(14;18)(q32;q21) as the primary chromosomal abnormality. None of the recurrent balanced translocations characteristic of extranodal MZL were seen secondarily in the nodal FLs with t(14;18)(q32;q21). However, 43/131 (33%) cases had at least one of the above secondary cytogenetic aberrations previously reported as recurrent aberrations in MZL and, when combined, these were significantly more frequent in FL with morphological evidence of marginal zone differentiation (p<0.0001, two-sided Fisher's exact test). Aberrations of chromosome 3 and, in particular, trisomy 3 occurred frequently in FL with marginal zone differentiation (p=0.002 and p<0.0001, respectively, two-sided Fisher's exact test), while chromosome 21, 22, and X chromosome aberrations, which have not been described previously as recurrent in MZL, were also significantly associated with marginal zone differentiation in FL (p=0.002, p=0.037, p=0.039, respectively, two-sided Fisher's exact test).

Cell Differentiation↗
PubMed2001

CD3+CD4-CD8-TCR-alphabeta+ T-cell lymphoma with clinical features of primary effusion lymphoma: an autopsy case.

We report an unusual case of T-cell lymphoma presenting as ascites. A 72-year-old HIV-negative woman was admitted to our hospital for abdominal discomfort associated with increasing abdominal girth over the course of 1 month. Physical examination showed a tense and distended abdomen and edema of the lower extremities. There was no hepatosplenomegaly or lymphadenopathy. A computed tomographic scan of the abdomen and chest showed massive ascites and pleural effusions, but there was no evidence of tumor masses or lymph node enlargement. The cytospin prepared from the peritoneal fluid was hypercellular and composed of a population of monotonous, large cells containing fine chromatin. No herpesvirus-8 (HHV-8) DNA was detected by polymerase chain reaction in the cells. Immunohistochemistry showed the neoplastic cells to be CD3+, CD4, CD7+. CD8-, CD34-, CD56, and TCR-alphabeta+. Repeated cytogenetic studies showed common abnormalities of del(1) (p11p22), +i(7)(ql0), and t(11:14)(q23;q11). The morphologic and immunologic findings were suggestive of peripheral T-cell lymphoma (PTCL), unspecified. This case suggests that some PTCLs with clonal chromosomal aberrations can exhibit peculiar serosal spreading in the absence of HHV-8 infection.

Aged↗
PubMed2002

Monoclonal antibody therapy for B-cell lymphoma: clinical trials of an anti-CD20 monoclonal antibody for B-cell lymphoma in Japan.

Twelve patients with relapsed CD20+ B-cell non-Hodgkin's lymphoma (B-NHL) were enrolled in a phase I study of rituximab; 4 received rituximab 250 mg/m2 and 8 received rituximab 375 mg/m2 once weekly for 4 weeks. Grade 1 or 2 infusion-related toxicity was observed. Of the 11 eligible patients, 2 achieved complete responses and 5 achieved partial responses. The elimination half-life (T1/2) of rituximab was 445 +/- 361 hours, and serum rituximab levels were detectable at 3 months. Thereafter, 90 relapse patients with indolent B-NHL or mantle cell lymphoma (MCL) were enrolled in a phase II study and treated with rituximab at 375 mg/m2 per infusion in 4 weekly infusions. Sixteen patients were ineligible in protocol compatible analyses. The overall response rates (ORR) in indolent B-NHL and MCL were 61% (37 of 61 patients) and 46% (6 of 13 patients), respectively. Factors affecting response and progression-free survival (PFS) were analyzed for 77 patients whose histopathology was centrally confirmed as indolent B-NHL or MCL. The ORR in patients receiving 1 prior chemotherapy regimen was higher than the ORR in those receiving > or = 2 regimens (P < .05). The median PFS was shorter in MCL patients, in those with extranodal disease, and in those receiving > or = 2 prior chemotherapy regimens (P < .01). The PFS of patients with higher serum rituximab levels (> or = 70 microg/mL) immediately before the third infusion was longer than that of other patients (P < .01). Several pretreatment factors and serum rituximab levels are useful for predicting the efficacy of rituximab monotherapy. Rituximab re-treatment was well tolerated in 13 patients with no grade 3 or 4 nonhematological toxicities. A partial response was observed in 5 patients (38%), and the median PFS after re-treatment was 5.1 months. In conclusion, rituximab is a highly effective agent in relapsed indolent and aggressive B-NHL and MCL and has acceptable toxicities.

Antibodies, Monoclonal↗
PubMed2002

Anaplastic large-cell lymphoma (Ki-1 lymphoma): ultrastructural and immunohistochemical studies.

We report an autopsy case of a malignant neutrophil-rich anaplastic large cell lymphoma (ALCL), which was reactive to the monoclonal antibody Ki-1 (CD30). This subtype of Ki-1 ALCL containing many neutrophils was named by Mann and colleagues in 1995, and its clinical and pathological characteristics have not been well described. In our case, the patient died 2 months after he first noticed an abdominal skin tumor. It was difficult to make the exact diagnosis of malignant lymphoma because the histological examination showed very poorly differentiated tumor cells. Ultrastructural observations revealed nuclei with convoluted contours and, sometimes, deep indentations, which suggested ALCL. Immunohistologically, most neoplastic cells were reactive with Ki-1 (CD30), leukocyte common antigen (LCA), and CD45RO (UCHL-1), and we confirmed Ki-1 ALCL. When we encounter poorly differentiated tumors on light microscopy, we should perform immunohistochemistry for hematological markers, such as LCA and Ki-1.

Adult↗
PubMed1992

Surface mu heavy chain expressed on pre-B lymphomas transduces Ca2+ signals but fails to cause growth arrest of pre-B lymphomas.

Little is known about the role of signals transduced by cell surface IgM (sIgM) expressed during early B cell development. A subclone (1.6) of the late pre-B cell lymphoma 70Z/3.12 was used to study signal transduction by surface mu heavy (H) chain before and after transition to the early immature B cell stage, and the functional consequences thereof. Although kappa L chain expression can be induced on 1.6 cells by LPS or cytokines, immunoprecipitations indicated that the non-induced 1.6 cells expressed mu H chain with an alternative protein(s) which may be a surrogate light chain(s). Consistent with this, anti-mu but not anti-kappa or anti-lambda antibodies caused transient Ca2+ mobilization in noninduced 1.6 cells. The Ca2+ signal was derived from both intracellular stores and Ca2+ influx in either noninduced cells or in cells that had been preinduced to express kappa L chain. Thus, the ability of mu H chain to mobilize Ca2+ as a second messenger does not depend upon the expression of mature L chains. The immature B lymphomas, WEHI-231 and CH1, express mature forms of IgM and undergo growth arrest when stimulated by anti-mu antibody. In contrast, signals generated by mu H chain on either noninduced or preinduced 1.6 cells or in the sIgM+ pre-B cell transfectant 300-19 mu lambda 36/8 did not cause growth arrest. These results suggest that mu H chain expressed on pre-B cells is capable of mobilizing Ca2+, but that this signal alone is insufficient to induce growth arrest in the pre-B cell.

B-Lymphocytes↗
PubMed1994

Hepatosplenic T-cell lymphoma: an unusual case of a gamma delta T-cell lymphoma with a blast-like terminal transformation.

We describe a case of a middle-aged women who presented with anemia and mild hepatosplenomegaly and who was found to have an unusual peripheral T-cell lymphoma with only subtle morphologically abnormal but mature-appearing cells noted in the blood and bone marrow. Less than 2 years after diagnosis the patient presented with an increasing white blood cell count to 26 x 10(9)/L, and numerous blasts were noted in the periphery. Flow cytometry studies showed cells with an unusual T-cell phenotype expressing the gamma delta T-cell receptor and restricted expression of the V delta 1 but not the V delta 2 protein, indicating the clonal nature of the proliferation. A clonal T-cell receptor gene rearrangement was seen with a V delta 1 probe. The patient died and was found at autopsy to have extensive hepatic sinusoidal infiltration by abnormal cells. The histopathologic, immunophenotypic, and molecular findings are those of "hepatosplenic T-cell lymphoma." In spite of the striking morphologic change during the course of the patient's disease the same phenotype and clonal rearrangement were found both at initial diagnosis and during terminal phase, indicating that this change represented a blast-like transformation of the patient's original lymphoproliferative disorder.

Female↗
PubMed1985

T lymphomas associated with human T-cell leukemia-lymphoma virus may show phenotypic and functional differences from adult T-cell leukemias.

We report phenotypic and functional characterization of lymph node cells from 27 patients with T lymphoma from the Nagasaki district of Japan. Nagasaki is one of several areas where adult T-cell leukemia is endemic, and sera from 18 of 23 patients examined (78.3%) were positive for antibody to adult T-cell leukemia-associated antigen. The majority of cases (24 of 27) showed the Leu-2a-, 3a+, MASO36c- phenotype similar to adult T-cell leukemia, but seemed to be subdivided into four groups according to the presence or absence of Leu-1 antigen and the receptor for sheep erythrocytes (SRBC). Eleven cases had both Leu-1 antigen and the receptor for SRBC (E-RFC+, Leu-1+, 2a-, 3a+), but 6 cases lacked Leu-1 antigen (E-RFC+, Leu-1-, 2a-, 3a+), 4 cases lacked receptors for SRBC (E-RFC-, Leu-1+, 2a-, 3a+), and 3 cases lacked both of these markers (E-RFC-, Leu-1-, 2a-, 3a+). The effects of lymph node T cells on pokeweed mitogen (PWM)-induced normal B-cell differentiation was studied in 10 cases. Lymph node T cells of 5 cases showed helper activity without any suppressor activity, and 2 cases showed suppressor activity with almost no detectable helper activity, similar to adult T-cell leukemia cells. Two other cases lacked particular functional effects. These results suggest the possibility that Leu-3a+ T-cell lymphoma may be functionally subdivided into at least two types, a helper type and a suppressor (adult T-cell leukemia) type.

Adolescent↗
PubMed1990

Abnormalities involving chromosome 6 in newly diagnosed patients with non-Hodgkin's lymphoma. Nebraska Lymphoma Study Group.

Several cytogenetic abnormalities involving chromosome 6 occurring in non-Hodgkin's lymphoma (NHL) have been described. We report 34 newly diagnosed patients with NHL who had an abnormal chromosome 6 on initial biopsy. Monosomies (n = 5), trisomies (n = 6), deletions of 6q (n = 13), and isochromosomes 6p (n = 9) were frequently observed and translocations were rare. As compared with 70 other NHL patients with cytogenetic abnormalities, the patients with an abnormal chromosome 6 had a higher frequency of immunoblastic lymphoma (p less than 0.001). These patients also were more likely to have B symptoms (p = 0.02). Patients with a breakpoint at 6q11-16 all had a deletion of the distal portion and also were more likely to have B symptoms (p less than 0.001). Most patients with breakpoints at 6q21-25 had a deletion associated with a lower frequency of stage IV disease (p = 0.03) and a higher complete remission (CR) rate (p = 0.03). The patients with an i(6p) had a lower frequency of stage IV disease (p = 0.03), and the patients with a trisomy 6 had a shorter median survival (p = 0.005). Our results suggest that chromosome 6, especially the long arm, carries important information for the clinical behavior of NHL. Future studies are necessary to resolve the molecular defects.

Adult↗
PubMed1993

Lymphomas of the head and neck. 1: Nasofacial T-cell lymphoma.

Nasofacial T-cell lymphoma includes diseases otherwise called "lethal midline granuloma" and "necrosis with atypical cells". It is characterised by relentless destruction of nose and palate in particular but the lymphoma remains localised to the head and neck. The age of onset ranges from 10 to 87 and the survival ranges from a few months to several years. The histological appearances are of a polymorphic infiltrate but including atypical T cells in a background of macrophages. There is a strong association with Epstein-Barr virus infection.

Facial Neoplasms↗
PubMed2005

mRNA expression patterns indicate CD30 mediated activation of different apoptosis pathways in anaplastic large cell lymphoma but not in Hodgkin's lymphoma.

One of the main functions of the tumor necrosis factor receptor (TNFR) family is induction of apoptosis. CD30, a member of the TNFR superfamily is overexpressed in highly proliferating tumors such as anaplastic large cell lymphoma (ALCL) and Hodgkin's lymphoma (HL). CD30 stimulation leads to apoptosis and growth arrest in cultured ALCL, but not in Hodgkin-Reed-Sternberg cells. To identify changes in the transcriptional program responsible for these opposing effects, we performed gene expression analysis in CD30-stimulated ALCL (Karpas 299) and HL (KM-H2) cell lines using cDNA microarrays. Selected genes were validated by real-time PCR. Hierarchical clustering was applied to the whole dataset and separated the cell lines clearly with respect to their origin. In HL, there were only minor CD30-specific alterations, whereas ALCL unequivocally showed a pronounced CD30-specific transcriptional response. Ninety-three genes (6.6% of total) were deregulated by more than a factor of two after CD30 stimulation in ALCL cells. The majority of genes identified are involved in cell cycle regulation and apoptosis. mRNA expression patterns further indicate that in contrast to HL, CD30 stimulation in ALCL induces cell death via the CD95-CD95 ligand (CD95L) pathway and the TNF-R1/TNF-R2 crosstalk. These data provide a detailed view on the transcriptional changes upon CD30 stimulation and may explain the observed functional differences of HL and ALCL.

Apoptosis↗
PubMed1999

Biochemical detection of novel anaplastic lymphoma kinase proteins in tissue sections of anaplastic large cell lymphoma.

The (2;5) translocation, found in many T-cell and null cell anaplastic large cell lymphomas (ALCLs), creates a hybrid gene encoding the 80-kd NPM-ALK protein. Typically neoplastic cells show labeling of both nucleus and cytoplasm for anaplastic lymphoma kinase (ALK) and for the N-terminus of nucleophosmin (NPM). However, 10-20% of cases exhibit cytoplasmic labeling only for ALK, indicating the probable presence of variants of the classical (2;5) translocation that do not involve the NPM gene. We report the detection (using Western blotting and an in vitro kinase assay) in seven such ALCL cases, of ALK proteins with molecular masses of 85 kd, 97 kd (one case exhibiting a (2;3)(p23;q21) translocation), 104 kd (one case carried a (1;2)(q21;p23) translocation), and 113 kd. Tyrosine kinase activity was detected in four of these proteins, but the N-terminal portion of NPM could not be detected. These results show how ALCL cases that express ALK proteins other than NPM-ALK can be detected by sensitive biochemical techniques using routine cryostat sections.

Animals↗
PubMed1998

T-cell-rich large-B-cell lymphomas contain non-activated CD8+ cytolytic T cells, show increased tumor cell apoptosis, and have lower Bcl-2 expression than diffuse large-B-cell lymphomas.

The factor(s) responsible for the reduced B cell number and increased T cell infiltrate in T-cell-rich large-B-cell lymphomas (TCRBCLs) have not been well characterized. We studied 18 TCRBCLs and 12 diffuse large-B-cell lymphomas (DLBCLs) to compare the 1) predominant T cell subpopulation(s), 2) expression of cytotoxic granule proteins (TIA-1 and granzyme B), 3) level of tumor cell apoptosis (Apoptag system, Oncor, Gaithersburg, MD), and 4) expression of Ki-67 (Mib-1) and apoptosis-related proteins (fas (CD95), bcl-2, and p53). T cells in TCRBCLs and DLBCLs were predominantly CD8+ T cells expressing alphabeta T-cell receptors and TIA-1 (16 of 18 TCRBCLs with >50% TIA-1+ small lymphocytes) but lacking granzyme B (16 of 18 TCRBCLs with <25% granzyme B+ small lymphocytes). Scattered apoptotic tumor cells (confirmed with CD20 co-labeling) were present in 15 of 18 TCRBCLs, with 14 of 15 cases having <10% apoptotic cells. No apoptotic cells were seen in 12 of 12 DLBCLs. In 16 of 16 immunoreactive TCRBCLs, <25% tumor cells were bcl-2+, whereas 6 of 12 DLBCLs had >50% bcl-2+ tumor cells. CD95 (fas) expression was also lower, with 3 of 18 (16.7%) TCRBCLs versus 4 of 12 (33%) DLBCLs having >25% CD95+ tumor cells. TCRBCLs and DLBCLs had similar levels of p53 and Ki-67 (Mib-1) expression. Thus, T cells in TCRBCLs are non-activated cytotoxic T lymphocytes (TIA-1+, granzyme B-). Tumor cell apoptosis (perhaps cytotoxic T cell mediated) may partly account for the decreased number of large (neoplastic) B cells in TCRBCLs, but other factors (ie, decreased bcl-2 expression) may also be needed.

Adolescent↗