Prognostic factors in multiple myeloma

Effect of allogeneic stem cell transplantation on bone marrow angiogenesis in chronic myelogenous leukemia

Increased bone marrow angiogenesis is a poor prognostic marker in patients with chronic myelogenous leukemia (CML). Allogeneic stem cell transplantation (ASCT) can be curative for patients with CML. Studies in myeloma have shown persistent increased bone marrow microvessel density (MVD) after autologous transplantation. It is not clear if abnormal bone marrow angiogenesis persists following a curative intervention like allogeneic transplantation. We evaluated MVD from bone marrow samples obtained just prior to and at 3-5 months after ASCT in 24 patients with CML. The median MVD pre-transplant was 14 (4-37), with 11 patients having high-grade angiogenesis and 13 having low grade. The median post transplant MVD was 20 (range 5-36), with 12 patients having high-grade angiogenesis and 12 low grade. The median time between biopsies was 4 months (range 1-6 months). The microvessels in the post transplant bone marrow appeared morphologically different with striking dilatation and sinusoidal appearance compared to the pre-transplant marrow. However, there was no significant change in MVD following transplant (P=0.8, paired t-test). Abnormal bone marrow angiogenesis appears to persist in the bone marrow following ASCT for CML, at least in the short term.

Polymorphic variation in GSTP1 modulates outcome following therapy for multiple myeloma

Glutathione S-transferase P1 (GSTP1) is a phase 2 drug metabolism enzyme involved in the metabolism and detoxification of a range of chemotherapeutic agents. A single nucleotide polymorphism (Ile105Val) results in a variant enzyme with lower thermal stability and altered catalytic activity. We hypothesized that patients with the less stable variant have a decreased ability to detoxify chemotherapeutic substrates, including melphalan, and have an altered outcome following treatment for multiple myeloma. We have assessed the impact of GSTP1 codon 105 polymorphisms in 222 patients entered into the Medical Research Council (MRC) myeloma VII trial (comparing standard-dose chemotherapy with high-dose therapy). In the standard-dose arm, patients with the variant allele (105Val) had an improved progression-free survival (PFS) (adjusted hazard ratios for PFS were 0.55 for heterozygotes and 0.52 for 105Val homozygotes, compared with 105Ile homozygotes; P for trend =.04); this was supported by a trend to improved overall survival, greater likelihood of entering plateau and shorter time to reach plateau in patients with the 105Val allele. No difference in outcome by genotype was found for patients treated with high-dose therapy. However, the progression-free survival advantage of the high-dose arm was seen only in patients homozygous for 105Ile (P =.008).

Bone marrow immunohistology of plasma cell neoplasms

The application of immunohistology to the spectrum of plasma cell disorders has yet to be incorporated widely into routine haematology practice. This technique enables the direct visualisation of specific surface and cytoplasmic antigens in the context of the individual cell and the surrounding anatomical neighbourhood. This review outlines the role of bone marrow immunohistology in the laboratory evaluation of patients with suspected and established plasma cell neoplasms and its emerging role in understanding myeloma biology for possible future therapeutic application.

Cases from the Osler medical service at Johns Hopkins University

A 56-year-old black woman with diabetes mellitus was admitted for hypoglycemia and confusion. Her past medical history included breast cancer, for which she had undergone a left lumpectomy and then mastectomy for in-breast recurrence. Her oral intake had decreased during the past month because of increasing discomfort from left-sided chest pain. During this period, she continued to take pioglitazone for diabetes at her originally prescribed dose. The patient's mental status improved quickly after taking orange juice and intravenous glucose, but the chest pain persisted. The pain, which was described as an ache along the left costal margin, increased with palpation, deep inspiration, or coughing. She had recently presented with similar complaints at another hospital where she had been prescribed a muscle relaxant that provided no relief from the pain. She also reported a 14-lb weight loss during the previous 3 months, as well as fatigue, weakness, and aches in her legs and arms. She denied fevers, chills, sweats, abdominal pain, nausea, or recent trauma. Laboratory values at the time of admission were: calcium, 11.8 mg/dL; total protein, 11.1 mg/dL; albumin, 3.2 g/dL; creatinine, 1.0 mg/dL; and hematocrit, 29.3%, with a mean corpuscular volume of 89.3. Chest radiography revealed a lytic lesion in the left lateral fourth rib and left humerus (). Serum and urine protein electrophoresis revealed a monoclonal spike in the gamma region consistent with monoclonal gammopathy. The serum spike was quantified at 3.78 g/dL. A skeletal survey showed many small well-defined lytic lesions in the skull (with one 1.5-cm lytic lesion in the upper posterior parietal bone), arms, and legs. A bone scan showed multiple foci of increased uptake in the right and left ribs as well as the proximal portion of the left femur. The peripheral blood smear revealed rouleaux formation () and plasma cells (). What is the diagnosis?

IL-6-independent expression of Mcl-1 in human multiple myeloma

Mcl-1 is a critical antiapoptotic survival factor for human multiple myeloma (MM). We examined the importance of IL-6 for Mcl-1 expression in five MM cell lines and in primary MM cells from 14 patients. While culture of MM.1S cells in IL-6 did induce Mcl-1 expression, four other MM cell lines exhibited high levels of Mcl-1 expression that were unaffected by IL-6. Similarly, Mcl-1 expression in 10 of 14 primary MM isolates was found to be IL-6-independent. An analysis of the mechanisms responsible for IL-6-independent Mcl-1 expression was undertaken. ERK1/2 activity did not influence Mcl-1 expression, distinct from Mcl-1 regulation that occurs during myeloid differentiation from hematopoietic progenitor cells. Inhibition of the PI3K pathway led to growth inhibition of 8226 and ANBL-6 cells without reduction of Mcl-1 levels, and high level Mcl-1 expression was maintained in the absence of activated STAT3. Analysis of the transcriptional activity of 5'-regulatory sequences from the human Mcl-1 gene in MM cells demonstrated high levels of IL-6-independent indicator gene activation as predicted. These data demonstrate that the mechanisms regulating Mcl-1 levels in MM cells are heterogeneous, and are often independent from IL-6 signaling pathways.

Review of 1027 patients with newly diagnosed multiple myeloma

OBJECTIVE

To determine the clinical and laboratory features of newly diagnosed multiple myeloma.

PATIENTS AND METHODS

Records of all patients in whom multiple myeloma was initially diagnosed at the Mayo Clinic in Rochester, Minn, from January 1, 1985, to December 31, 1998, were reviewed.

RESULTS

Of the 1027 study patients, 2% were younger than 40 years, and 38% were 70 years or older. The median age was 66 years. Anemia was present initially in 73% of patients, hypercalcemia (calcium level > or = 11 mg/dL) in 13%, and a serum creatinine level of 2 mg/dL or more in 19%. The beta2-microglobulin level was increased in 75%. Serum protein electrophoresis revealed a localized band in 82% of patients, and immunoelectrophoresis or immunofixation showed a monoclonal protein in 93%. A monoclonal light chain was found in the urine in 78%. Nonsecretory myeloma was recognized in 3% of patients, whereas light-chain myeloma was present in 20%. Conventional radiographs showed an abnormality in 79%. The plasma cell labeling index was 1% or more in 34% of patients. Multivariate analysis revealed that age, plasma cell labeling index, low platelet count, serum albumin value, and the log of the creatinine value were the most important prognostic factors.

CONCLUSION

The median duration of survival was 33 months and did not improve from 1985 through 1998.

Bone marrow angiogenesis in multiple myeloma: effect of therapy

Recent studies have demonstrated that angiogenesis has a role in haematological malignancies, including multiple myeloma. Multiple myeloma is characterized by inevitable relapse after standard or high-dose chemotherapy. To study the effect of chemotherapy on bone marrow angiogenesis in patients with multiple myeloma, we used two methods to evaluate bone marrow angiogenesis in patients with newly diagnosed multiple myeloma, comparing these findings with those from bone marrow obtained after standard chemotherapy. Before therapy, an increased degree of bone marrow angiogenesis and a high bone marrow plasma cell labelling index (PCLI) were predictive of poorer survival. As estimated by microvessel density (MVD), the median survivals for patients with low-grade, intermediate-grade and high-grade angiogenesis were 77, 30 and 14 months respectively. After therapy, the MVD did not change significantly. However, when patients with at least a partial response were considered separately, they showed a decrease in MVD. Post-therapy PCLI was predictive of survival, but post-therapy MVD was not. There was good correlation between angiogenesis estimated by visual grading and that determined by MVD assessment. We conclude that the degree of bone marrow angiogenesis is a prognostic marker in patients with multiple myeloma and does not decrease significantly after therapy.

Proliferation of IL-6-independent multiple myeloma does not require the activity of extracellular signal-regulated kinases (ERK1/2)

The evolutionarily conserved Ras/Raf/MEK/ERK pathway is thought to be essential for proliferation of eukaryotic cells. The human multiple myeloma (MM) cell line 8226 encodes an activated K-ras allele and proliferates without requirement for the main MM growth and survival factor IL-6. Surprisingly, the addition of the MEK1/2 inhibitors PD98059 or U0126 to 8226 cultures at doses that block virtually all ERK1/2 activity had minimal effects on the rapid proliferation of this cell line. In contrast, proliferation of the IL-6-dependent MM cell line, ANBL-6 was blocked by PD98059. Levels of activated forms of the other classical MAP kinases (JNK and p38) were very low during MM cell proliferation and, therefore, do not substitute for the mitogenic activities normally regulated by ERK kinases. These data demonstrate that proliferation of 8226 cells does not require ERK1/2 activity, and suggest that IL-6-independent growth of MM may correlate with independence from a requirement for ERK activity. Other signal transduction pathways that appear to regulate cell cycle progression in these cells were examined.

Clinical activity of arsenic trioxide for the treatment of multiple myeloma

Arsenic has been used since ancient times as a therapeutic agent. However, until recently its use in modern medicine has been restricted to the treatment of a limited number of parasitic infections. In the early 1990s, reports from China described impressive results with arsenic trioxide in patients with de novo, relapsed, and refractory acute promyelocytic leukemia (APL). Other investigators subsequently confirmed these results leading to approval of its use for relapsed or refractory APL in the United States. Investigations of this agent have demonstrated that its efficacy in APL and preclinical tumor models is dependent upon a number of mechanisms, including induction of apoptosis, effects on cellular differentiation, cell cycling, and tumor angiogenesis. Subsequent preclinical studies showed significant activity of arsenic trioxide in multiple myeloma (MM). Based on this, in a phase II trial, we have evaluated the activity of arsenic trioxide in 14 patients with relapsed MM, refractory to conventional salvage therapy. With the dose and schedule used, treatment with arsenic trioxide produced responses in three patients and prolonged stable disease in a fourth patient, with the longest response lasting 6 weeks. Although treatment was reasonably well tolerated, in these patients with extensive prior therapy, 11 developed cytopenia, five associated with infectious complications and three developed deep vein thromboses. The results of this small trial support further investigation of this novel drug for the treatment of patients with relapsed or refractory MM.

Thalidomide for the treatment of relapsed and refractory multiple myeloma

Thalidomide is the first drug in over 20 years to demonstrate clinically significant activity in patients with multiple myeloma. Although the survival rate has not improved with conventional chemotherapy over the last 30 years, thalidomide has produced favorable responses in patients for whom most available therapies have failed, such as those whose disease was resistant or relapsed after standard and high-dose treatments. Despite the risk of adverse effects such as sedation and constipation, thalidomide has become an alternative therapy for patients with relapsed or refractory disease. New trials with thalidomide administered alone and in combination with other agents seem to show promise in patients with multiple myeloma, as do preliminary studies with thalidomide derivatives.

Proliferation, apoptosis, and intratumoral vascularity in multiple myeloma: correlation with the clinical stage and cytological grade

AIMS

Abnormalities involving proliferation, apoptosis, and angiogenesis are important in tumorigenesis. The purpose of this study was to examine these three biological processes, and their relation with the clinical stage and cytological grade in multiple myeloma (MM).

METHODS

Fifty four newly diagnosed patients with MM were studied by immunohistochemistry using bone marrow clot sections. Proliferation and apoptosis were evaluated for the proportion of MM cells (indicated by morphology and CD138 reactivity) positive for the Ki67 antigen and single stranded DNA (ssDNA), respectively. Angiogenesis was evaluated by measuring the intratumoral microvessel density (IMVD) and by assessing the immunoreactivity of vascular endothelial growth factor (VEGF).

RESULTS

There were 30 men and 24 women (median age, 65 years; range, 37-84). At initial presentation, 15 (28%) were in Durie stage I, 15 (28%) in stage II, and 24 (44%) in stage III. Advanced clinical stage correlated with high cytological grade (p < 0.03). The medians for Ki67, ssDNA, and IMVD were 4.4% (range, 0-15%), 0.2% (range, 0-2.8%), and 15.5 (range, 0-63), respectively. Among these three continuous parameters, the only significant correlation was that between Ki67 and IMVD (p < 0.0001). Both Ki67 and IMVD also correlated with the clinical stage, cytological grade, and VEGF positivity (p <0.05). No correlation was found between ssDNA and all of the other parameters.

CONCLUSIONS

These data suggest that proliferation is associated with angiogenesis in MM. Furthermore, proliferation and angiogenesis, but not apoptosis, may be important in disease progression. Lastly, increased production of VEGF may be one of the contributing factors to the increase in intratumoral vascularity seen in advanced MM.

Myeloid cell factor-1 is a critical survival factor for multiple myeloma

Multiple myeloma (MM) is characterized by the accumulation of malignant plasma cells in the bone marrow caused primarily by failure of normal homeostatic mechanisms to prevent the expansion of postgerminal center plasma cells. We have examined the molecular mechanisms that promote the survival of MM cells and have identified a key role for myeloid cell factor-1 (Mcl-1), an antiapoptotic member of the Bcl-2 family. These experiments were initiated by the observation that MM cells were exquisitely sensitive to culture in the presence of actinomycin D: caspase activation occurred within 3 hours of treatment and cells were not protected by interleukin-6, the main MM cell growth and survival factor. Actinomycin D-induced apoptosis was blocked by proteasome inhibitors, suggesting that a labile protein was required for MM cell survival. Further analysis demonstrated that Mcl-1 was likely to be the labile factor governing MM cell survival. Mcl-1 protein levels decreased rapidly after culture in the presence of actinomycin D in concordance with effector caspase activation, but addition of proteasome inhibitors reversed the loss of Mcl-1 and maintained cell viability. The levels of other antiapoptotic proteins, including Bcl-2 and members of the inhibitors-of-apoptosis family, were unaffected by these interventions. Furthermore, Mcl-1 antisense oligonucleotides caused a rapid down-regulation of Mcl-1 protein levels and the coincident induction of apoptosis, whereas overexpression of Mcl-1 delayed actinomycin D-induced apoptosis with kinetics that correlated with expression levels of Mcl-1. These data indicate that Mcl-1 expression is required for the survival of MM cells and may represent an important target for future therapeutics.

Arsenic trioxide in multiple myeloma: rationale and future directions

Multiple myeloma remains an incurable malignancy with a median survival that does not exceed 3 years. At least one third of patients with multiple myeloma fail to respond to induction chemotherapy, and those who initially achieve remission eventually relapse and require additional therapy. Recent reports demonstrating the efficacy of arsenic trioxide in acute promyelocytic leukemia have prompted a revival in the clinical use of this compound. The achievement of clinical responses marked by molecular conversion of the malignant phenotype and remissions in patients who had failed to respond to multiple courses of conventional chemotherapy provided the impetus to explore its use in multiple myeloma. Properties that favor the use of arsenic trioxide are its ability to target selectively malignant cells for apoptosis through enhancementof reactive oxygen species, to induce differentiation, and to inhibit angiogenesis. Multiple events involved in the pathogenesis of multiple myeloma coincide with pathways targeted by arsenic trioxide, and early results have suggested that clinical responses and safety in patients are promising with advanced disease.

CD44 isoforms are differentially regulated in plasma cell dyscrasias and CD44v9 represents a new independent prognostic parameter in multiple myeloma

To evaluate the role of CD44 variant isoforms (CD44v) in plasma cell dyscrasias, CD44v expression was analysed in bone marrow (BM) biopsies of multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) patients, in biopsies of soft tissue infiltration by MM and in extramedullary plasmacytoma samples. Expression of CD44 isoforms containing the 3v, 4v, 6v or 10v domain was observed in 15, 7, 13 and 5% of 87 samples from 49 consecutive MM cases, but could not be detected in ten normal persons or 11 MGUS patients. In contrast, CD44v9 revealed a broader pattern of expression and was observed in plasma cells in three out of ten normal persons and in three out of 11 MGUS cases. In MM, CD44v9 was detected in 32 out of 87 samples (37%) of BM infiltrates and was associated with an advanced Durie and Salmon stage (P<0.03), a progressive disease (P<0.01) and an IgA subtype (P<0.01). Furthermore, CD44v9 expression was observed in three out of five cases of MM soft tissue infiltrates, was often upregulated during disease progression, was significantly correlated with a shorter overall survival (P<0.03) and emerged as an independent prognostic factor in multivariate analysis (stage: relative risk 1.36, P<0.02; CD44v9 expression: relative risk 1.45, P<0.04). These results substantiate the clinical relevance of CD44v domains in plasma cell disorders and establish CD44v9 as a new independent prognostic parameter in MM.

Arsenic trioxide: an emerging therapy for multiple myeloma

Arsenic trioxide can inhibit proliferation and induce apoptosis in multiple myeloma (MM) cells in vitro and in vivo. In addition to affecting tumor growth, arsenic trioxide has been shown to inhibit angiogenesis, suggesting that it may have significant potency in the treatment of MM. Based on these observations, the clinical efficacy of arsenic trioxide was evaluated in patients with advanced refractory MM using a fixed-dose intravenous infusion given daily for a maximum of 60 days. Nine patients were evaluable. All nine had extensive prior therapy; seven had two or more high-dose chemotherapy cycles with autologous stem cell support. All nine patients had cytogenetic abnormalities, and six had chromosome 13 deletions. Of the four patients who completed more than 30 days of arsenic trioxide infusion, two had >50% reduction in myeloma paraprotein, one had stable disease, and one progressed. Of the five patients with <30 days infusion, two had stable disease and three progressed. Thus, on an intent-to-treat basis, two of nine (23%) patients responded (>50% paraprotein reduction). The regimen was well tolerated except for development of cytopenia, which responded to G-CSF, and a grade III pulmonary complication in one patient. In summary, arsenic trioxide has activity in end-stage, high-risk myeloma and deserves further evaluation in earlier-stage disease.

Blood levels of immune cells predict survival in myeloma patients: results of an Eastern Cooperative Oncology Group phase 3 trial for newly diagnosed multiple myeloma patients

Previously, it was reported that patients with multiple myeloma (MM) who have higher baseline levels of blood CD4(+) or CD19(+) cells have longer survival. This article extends the analysis of immune cell levels and survival in a large cohort (N = 504) of patients with MM entered on Eastern Cooperative Oncology Group (ECOG) phase 3 trial (9486). Newly diagnosed patients with MM received 2 cycles of vincristine, bischloroethylnitrosourea, melphalan, cytoxan, prednisone (VBMCP) and were treated on one of 3 randomized arms: VBMCP with either interferon or high-dose cyclophosphamide, or VBMCP alone. Blood immune cell levels were studied at trial entry (baseline), after 2 cycles of chemotherapy, after 2 years of therapy, and at relapse. Baseline CD3(+), CD4(+), CD8(+), CD19(+), and CD4(+) subset cell levels were all positively associated with survival (P =.0087 to P <.0001). A multivariate analysis incorporating CD4(+) and CD19(+) cell levels defined 3 separate groups of patients with MM to survival outcome. Higher CD19(+) blood levels were positively associated with MM-patient survival at entry to the study, at year 2, and at relapse (P <.0001 at all 3 timepoints). Patients with MM had evidence of immune cell reconstitution after 2 years of therapy, but the rate and extent of recovery was greater for CD8(+), which was greater than CD4(+), which was greater than CD19(+). This latter data affirms the positive relationship between the quantitative status of the blood immune system in MM and survival. In addition, the importance of the CD19(+) blood cells to survival is evident throughout the course of MM. Therapeutic efforts to maintain an intact immune system may be crucial in maximizing chemotherapeutic and/or immunotherapy efforts in this disease.

A high bone marrow plasma cell labeling index in stable plateau-phase multiple myeloma is a marker for early disease progression and death

The plasma cell labeling index (PCLI) is a measure of plasma cell proliferative activity and is an important prognostic factor in newly diagnosed multiple myeloma (MM). Occasionally patients have been observed with stable, plateau phase MM with minimal numbers of residual light-chain-restricted monoclonal plasma cells, but a high PCLI. No data are available on the outcomes for such patients. Data from 57 patients with plateau phase MM and a marrow PCLI of more than 1.0% were compared with 105 matched control patients with MM with a marrow PCLI of less than 1.0%. All patients had less than 10% total plasma cells on marrow aspirate and biopsy. The median time to progression and overall survival were 8 months and 20 months, respectively, in the high PCLI group versus 39 months and 56 months, respectively, in the low PCLI group (P < .0001). These findings suggest that a high PCLI in patients with apparently stable, plateau phase MM is an adverse parameter that may predict a short time to disease progression and death.

Expression of a free gamma heavy chain in serum following autologous stem cell transplantation for IgG kappa multiple myeloma

A 41-year-old male with IgG kappa multiple myeloma is described. He developed a free gamma heavy chain without an accompanying light chain following high-dose chemotherapy and autologous peripheral blood stem cell transplantation. The free gamma heavy chain was detected in serum and urine specimens 2 months after transplant, and eventually evolved into an IgG kappa monoclonal protein with electrophoretic properties similar to the original myeloma protein. Although the origin of the free gamma heavy chain remains uncertain, it was most likely related to the underlying plasma cell malignancy and, therefore, was an early sign of disease relapse.

Immunophenotypic Aberrations, DNA Content, and Cell Cycle Analysis of Plasma Cells in Patients with Myeloma and Monoclonal Gammopathies

We describe the immunophenotypic and gross DNA defects in 55 patients with myeloma and 50 patients with monoclonal gammopathy and review the literature on this subject (MedLine, 1994-2000). Our data confirmed previous reports indicating that in myeloma nearly all marrow plasma cells are abnormal (98.7 +/- 8.1%). In monoclonal gammopathy the fraction of abnormal plasma cells was 35.0 +/- 32.8%. In both myeloma and monoclonal gammopathy, the most frequent aberrant phenotypic features consisted of absence of expression of CD19, strong expression of CD56, and decreased intensity of expression of CD38; aberrant expression of CD10, CD20, CD22, or CD28 was observed in less than one-third of myeloma cases. The vast majority of cases had two or more phenotypic aberrations. In the DNA studies, 7% of myeloma cases were biclonal and 93% of cases were monoclonal. In those studies with only one plasma cell mitotic cycle, 37% had normal DNA content and 63% were aneuploid (hyperploid, 61%; hypoploid, 2%). The mean percentages of plasma cells in S- and G2M phases were 4.9 +/- 8.5 and 4.4 +/- 6.9%, respectively. Thirty-eight percent of cases had more than 3% of plasma cells in S phase. In monoclonal gammopathy, the DNA index of abnormal plasma cells ranged from 0.89 to 1.30 and the percentage of diploid (31%) and aneuploid (69%) cases was not different from the results found in myeloma. The differences in percentage of abnormal plasma cells in S- (7.4 +/- 8.6%) and G2M-phases (2.4 +/- 1.7%) in patients with monoclonal gammopathy were not statistically significant.

Effect of complete response on outcome following autologous stem cell transplantation for myeloma

We studied the effect of complete response (CR) among 126 consecutive patients who underwent stem cell transplantation (SCT) for myeloma. The CR rate with SCT was 33%. Median overall survival (OS) from diagnosis of myeloma was 56 months. OS following SCT was 22 months. Progression-free survival (PFS) was 12 months. OS was not different between patients who achieved CR and those who did not, median survival 25 vs 24 months, P = 0.5. Corresponding median times for PFS were 15 and 11 months, P = 0.2. The plasma cell labeling index (PCLI) was high (> or = 1%) in 36% (high risk group) and was associated with poor OS and PFS (P < 0.001). Achieving CR did not influence OS or PFS in either the high or the low risk group. In contrast, OS and PFS were significantly influenced by high PCLI both in patients who achieved CR and those who did not. OS was poor (< 30 months) in high risk patients regardless of CR status and in low risk patients who did not achieve CR, compared to low risk patients achieving CR (57 months), making them candidates for novel post-transplant treatment options. Outcome following SCT is dependent more on biological variables such as the PCLI than on CR status.

Recurring chromosomal abnormalities in non-Hodgkin's lymphoma: biologic and clinical significance

Non-Hodgkin's lymphomas (NHLs) are a group of clinically important neoplasms with a complex biology that makes their classification and treatment difficult. Their incidence is increasing and they cause significant morbidity and mortality. NHLs result from transformation of B and T/natural killer (NK) cells. Their genetic hallmark is chromosomal translocations resulting from aberrant rearrangements of IG and TCR genes, which lead to inappropriate expression of genes at reciprocal breakpoints that regulate a variety of cellular functions, including gene transcription, cell cycle, apoptosis, and tumor progression. Cytogenetics followed by molecular genetic analysis of some of the recurring translocations continues to provide new insights into lymphomagenesis and cell biology. More recently, chromosomal and gene amplification and gene deletion have been recognized as frequent genetic changes that may play a role in lymphoma progression and clinical behavior. In this review, cytogenetic data pertaining to recurring chromosomal changes on lymphomas are reviewed and examined in relation to their relevance to lymphoma development, classification, and clinical behavior.