T-cell non-Hodgkin lymphoma

Cyclosporin in subcutaneous panniculitis-like T-cell lymphoma

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare form of hematologic malignancy characterized by lesions in subcutaneous fat associated with systemic symptoms. The standard treatment of the disease, currently, is not established, but CHOP or CHOP-like regimens are usually given. We report, herein, 4 cases of SPTCL diagnosed by histopathology and immunohistochemistry who were refractory to CHOP and/or ESHAP and/or fludarabine-based regimen, but showed rapid improvement within weeks after oral cyclosporin 4 mg/kg/day. Three sustained complete remission for the durations of 8 - 9 months off-treatments. T-cell receptor gene rearrangement revealed polyclonality in 3 cases and monoclonality in 1 case. Our data suggest the benefit of incorporating cyclosporin into the treatment regimen for SPTCL.

Bcl-10 protein highly correlates with the expression of phosphorylated p65 NF-kappaB in peripheral T-cell lymphomas and is associated with clinical outcome

AIMS

In T cells, protein kinase C (PKC) theta plays a major role in T-cell receptor (TCR)-mediated activation of a novel nuclear factor (NF)-kappaB pathway that involves phosphorylation of p65 at serine 536 (Pp65(Ser536)). Bcl-10 acts along the same pathway downstream of PKC theta to activate NF-kappaB. The aim was to investigate the relationship between the expression of PKC theta, Bcl-10 and P-p65(Ser536) proteins and their prognostic significance in peripheral T-cell lymphomas (PTCLs).

METHODS AND RESULTS

Paraffin-embedded tissues from 30 patients with PTCLs treated with curative intention were evaluated retrospectively. Expression of PKC theta, Bcl-10 and P-p65(Ser536) proteins was assessed using immunohistochemistry. Expression of PKC theta was detected in 22 of 30 cases (73%), Bcl-10 in 20 of 30 (67%) and P-p65(Ser536) in 21 of 30 (70%). Bcl-10+ tumours were associated with PKC theta (18 of 22) (P < 0.0001) and Pp65Ser536 (19 of 21) expression (P < 0.0001). Patients with Bcl-10+ or P-p65(Ser536+) tumours fared better, with a 5-year overall survival of 48 and 45%, respectively, versus 0% for negative tumours (P = 0.029 and P = 0.04, respectively).

CONCLUSIONS

Bcl-10 is expressed in PTCLs, correlates with PKC theta and Pp65(Ser536) expression and seems to be associated with better survival.

Clinicopathologic characteristics of T-cell non-Hodgkin's lymphoma: a single institution experience

BACKGROUND/AIMS

Although the incidence of T-cell non-Hodgkin's lymphoma (NHL) is higher in Far East Asia than in Western countries, its incidence and clinical course in Korea are not well-defined. Therefore, we assessed the relative frequency and clinical features of T-cell NHL in Korea.

METHODS

We performed a retrospetcive analysis of 586 patients with NHL.

RESULTS

101 (17.2%) had T-cell NHL. The most frequent subtypes of T-cell NHL were extranodal NK/T-cell lymphoma, nasal type (NASAL), peripheral T-cell lymphoma, unspecified type (PTCL-U), and anaplastic large cell lymphoma, T/null cell, primary systemic type (ALCL). The seven pathological subtypes could be classified into three prognostic subgroups. When patients with the three most frequent subtypes were grouped together, their survival was reflected in the International Prognostic Index (IPI) scores. Univariate analysis of IPI elements and other clinical features showed that clinical stage and extranodal sites were significant predictors of survival. Cox multivariate analysis showed that the number of extranodal sites was the only independent prognostic indicator.

CONCLUSIONS

The relative frequency of T-cell NHL seems to be decreasing in Korea, although NASAL remains frequent. Korean patients with ALCL appear to have an unfavorable prognosis. Large-scale studies are warranted for Korean patients with T-cell NHL.

Array comparative genomic hybridization analysis of PTCL-U reveals a distinct subgroup with genetic alterations similar to lymphoma-type adult T-cell leukemia/lymphoma

PURPOSE

Peripheral T-cell lymphoma, unspecified (PTCL-U) comprises histopathologically and clinically heterogeneous groups. The purpose of this study was to identify subgroups with distinct genetic, histopathologic, and prognostic features.

EXPERIMENTAL DESIGN

We used array comparative genomic hybridization (CGH) for high-resolution analysis of 51 PTCL-U patients and the array data for examining possible correlations of histopathologic and clinical features. Moreover, we compared the genetic, histopathologic, and prognostic features of the PTCL-U cases with those of 59 cases of lymphoma-type adult T-cell leukemia/lymphoma (ATLL).

RESULTS

We identified 32 regions with frequent genomic imbalance, 1 region with high copy number gain at 14q32.2, and 1 region with homozygous loss at 9p21.3. Gains of 7p and 7q and loss of 9p21.3 showed a significant association with poor prognosis. PTCL-U cases with genomic imbalance showed distinct histopathologic and prognostic features compared with such cases without alteration and a marked genetic, histopathologic, and prognostic resemblance to lymphoma-type ATLL.

CONCLUSIONS

The array CGH enabled us to identify the frequently altered genomic regions with strong prognostic power among PTCL-U cases. A correlative analysis using the array CGH data disclosed a subgroup in PTCL-U with genomic alterations and with histopathologic and clinical relevance. In addition to histopathologic similarity, the strong genetic and prognostic resemblance between PTCL-U cases with genomic imbalance detected by array CGH and lymphoma-type ATLL seems to support the notion that the former may constitute a distinct PTCL-U subgroup.

131I anti-CD45 radioimmunotherapy effectively targets and treats T-cell non-Hodgkin lymphoma

Radioimmunotherapy (RIT) options for T-cell non-Hodgkin lymphomas (T-NHLs) are limited. We evaluated anti-CD45-RIT in human (h) and murine (m) T-NHL. CD45 was highly expressed on hT-NHL patient samples (median, 2.3 x 10(5) antigen-binding capacity units/cell) and hT-NHL cell lines (3.4 x 10(5) CD45 antigen-binding capacity units/cell). Biodistribution studies in hTNHL xenografts showed that (131)I-labeled BC8 (anti-hCD45) delivered 154% (P = .01) and 237% (P = .002) more radioiodine to tumor sites over control antibodies at 24 hours and 48 hours, respectively. Importantly, tumor sites targeted with (131)I-BC8 exhibited 2.5-fold (P = .05), 3.0-fold (P = .007), and 3.6-fold (P = .07) higher (131)I retention over the nontarget organs of lungs, liver, and kidneys, respectively (24 hours). Because the clinical use of anti-hCD45 would target both T-NHL and other hematolymphoid tissues, we evaluated the ability of anti-mCD45 to target mT-NHL. mT-NHL grafts targeted with anti-mCD45 correspondingly retained 5.3 (P < .001), 5.4 (P < .001), and 8.7 (P < .001) times the radioactivity in tumor sites compared with nontarget organs of lung, liver, and kidney. (131)I-labeled BC8 therapy yielded improved complete remission rates (75% vs 0%, P < .001) and progression-free survivals (median, 23 days vs 4.5 days, P < .001) compared with controls. These data indicate that the high CD45 expression of T-NHL allows reliable tumor targeting and disease control supporting anti-CD45 RIT for T-NHL patients.

Cutaneous lymphoma incidence patterns in the United States: a population-based study of 3884 cases

There have been no prior large population-based studies focusing on cutaneous lymphomas (CL) in the United States. Using the Surveillance, Epidemiology and End Results (SEER) program data, we analyzed age-adjusted CL incidence rates (IRs) and survival rates by sex and race/ethnicity. There were 3884 CLs diagnosed during 2001-2005. Cutaneous T-cell lymphomas (CTCLs) accounted for 71% (age-adjusted incidence rate [IR] = 7.7/1 000 000 person-years), whereas cutaneous B-cell lymphomas(CBCLs) accounted for 29% (IR = 3.1/1 000 000 person-years). Males had a statistically significant higher IR of CL than females (14.0 vs 8.2/1 000 000 person-years, respectively; male-female IR ratio [M/F IRR] = 1.72; P < .001). CL IRs were highest among blacks and non-Hispanic whites (both 11.5/1 000 000 person-years), followed by Hispanic whites (7.9) and Asian/Pacific Islanders (7.1). The CTCL IR was highest among blacks (10.0/1 000 000 person-years), whereas the CBCL IR was highest among non-Hispanic whites (3.5). Over the past 25 years, the CL IR increased from 5.0/1 000 000 person-years during 1980-1982 to 14.3 during 2001-2003. During 2004-2005, the CL IR was 12.7. This recent apparent change could be incomplete case ascertainment or potential leveling off of IRs. CLs rates vary markedly by race and sex, supporting the notion that they represent distinct disease entities.

Pathobiology of mature T-cell lymphomas

Mature T- and natural killer (NK)-cell neoplasms are relatively rare forms of leukemia/lymphoma. The diagnosis of these entities is often difficult, necessitating extensive immunophenotypic, molecular, and genetic testing. Despite the accumulating information on the pathobiology of these neoplasms, in many cases the prognosis remains poor. This article presents an updated view of the morphologic, immunophenotypic, genetic, and molecular characteristics of the mature T- and NK-cell neoplasms. For a better understanding of this complex topic, the development of normal T and NK cells is briefly discussed. The presentation of the characteristic features of the neoplasms in the 2008 World Health Organization classification of hematopoietic neoplasms includes advances in the understanding of the pathobiology of each diagnostic category.

Peripheral T-cell lymphoma with follicular T-cell markers

INTRODUCTION

Peripheral T-cell lymphomas (PTCLs) in western countries are uncommon tumors with unfavorable prognosis. They may be subclassified as anaplastic large-cell lymphomas (ALCLs), angioimmunoblastic-T-cell lymphomas (AITLs), or unspecified peripheral T-cell lymphomas (PTCLs-U). It has recently been demonstrated that AITLs originate from germinal center follicular helper T cells (TFH), whereas the normal counterparts of other PTCLs remain essentially unknown. The aim of this study was to establish whether other PTCL subgroups also express TFH cell markers.

MATERIALS AND METHODS

One hundred forty-six PTCLs were analyzed for programmed death-1 (PD-1) expression in tissue microarrays using a new monoclonal antibody called NAT-105. PD-1-positive cases, which did not fulfill all the criteria for AITL, were further evaluated in whole-tissue sections for another 12 immunohistochemical markers, including the TFH cell markers CXCL13, CD10, and BCL6. Clonal Ig and T-cell receptor rearrangements and Epstein-Barr virus-encoded RNA expression were also evaluated. Morphologic, clinical, and follow-up data were reviewed.

RESULTS

Twenty-five out of 87 non-AITL cases (28.75%) showed PD-1 immunostaining. CXCL13, BCL6, and CD10 expression was found in 24/25 (96%), 16/25 (64%), and 6/25 (24%) cases, respectively. All cases expressed at least 2 TFH cell markers. Moreover, 5 cases were positive for all 4 markers. Most cases (17/25, 68%) displayed some AITL-like features. Of the remainder, 1 was considered to be early AITL, 1 was diagnosed as ALCL-anaplastic lymphoma kinase-negative, and 4 of the other 6 PTCLs-U had morphology consistent with lymphoepithelioid (Lennert's) lymphoma. Three AITL-like cases showed IgH clonal rearrangement, 2 of which were associated with Epstein-Barr virus expression. Our series of patients did not differ significantly in their clinical presentation from most reported PTCL cases in the literature: 55% of them were alive and 35% were in complete remission after a median follow-up of 15 months after cyclophosphamide, dexorubicin, vincristine, and prednisone-based chemotherapy.

CONCLUSIONS

TFH cell markers, especially PD-1, were expressed in a subset of PTCLs not classified as AITL, although most of them shared some morphologic features with AITL. This suggests that the spectrum of AITL may be wider than previously thought, possibly including cases of lymphoepithelioid (Lennert's) lymphoma. Additionally, the results suggest that a subgroup of PTCLs-U, distinct from AITL and including some cases denominated as ALCL, may also be derived from TFH cells, although they develop along a distinct pathogenic pathway.

Low frequency of Epstein Barr virus association and high frequency of p53 overexpression in an Argentinean pediatric T-cell lymphoma series

T-cell non-Hodgkin's lymphomas (NHLs) represent 10% to 15% of all diagnosed lymphomas in Western countries. Various geographic frequencies of T-cell NHL have been documented, in part reflecting increased exposure to pathogenic factors such as Epstein-Barr virus (EBV). Our aims were to assess EBV and p53 expression in Argentine pediatric T-cell lymphoma and to correlate them with patients' survival. Epstein-Barr encoded RNAs (EBERs) in situ hybridization and LMP1 and p53 immunohistochemical staining were performed on formalin-fixed paraffin-embedded lymph node biopsies from 25 pediatric T-lymphoma patients. In 17 of 25 samples good-quality DNA was obtained, and EBER polymerase chain reaction was assessed to confirm in situ hybridization and immunohistochemical results. Epstein-Barr virus expression was found in 8.0% of cases. p53-positive staining was distributed in 92% of pediatric cases. Kaplan-Meier survival analysis showed that neither EBV nor p53 expression was statistically significantly associated with event-free survival. Our data showed a low frequency of EBV association with pediatric T-cell lymphoma. It seems that p53 plays an important role in proliferation in our studied population, since it is overexpressed in 92% of T-cell lymphoma cases.

Illegitimate WNT pathway activation by beta-catenin mutation or autocrine stimulation in T-cell malignancies

Recent studies in mice have shown a role for the canonical WNT pathway in lymphocyte development. Because cancers often arise as a result of aberrant activation of signaling cascades that normally promote the self-renewal and expansion of their progenitor cells, we hypothesized that activation of the WNT pathway might contribute to the pathogenesis of lymphoproliferative disease. Therefore, we screened a large panel (n = 162) of non-Hodgkin lymphomas (NHL), including all major WHO categories, for nuclear expression of beta-catenin, a hallmark of "active" WNT signaling. In 16 lymphomas, mostly of T-lineage origin, nuclear localization of beta-catenin was detected. Interestingly, some of these tumors contained established gain-of-function mutations in the gene encoding beta-catenin (CTNNB1); however, in the majority, mutations in either CTNNB1 or APC were not detected. Functional analysis of WNT signaling in precursor T-lymphoblastic lymphomas/leukemias, the NHL subset in which beta-catenin accumulation was most prevalent (33% positive), revealed a constitutively activated, but still responsive, WNT pathway, which controlled T-cell factor-mediated gene transcription and cell growth. Our data indicate that activation of the WNT pathway, either by CTNNB1 mutation or autocrine stimulation, plays a role in the pathogenesis of a subset of NHLs, in particular, those of T-cell origin.

An extranodal NK/T cell lymphoma, nasal type, with specific immunophenotypic and genotypic features

Extranodal NK/T cell lymphoma, 'nasal type,' is a rare clinicopathological entity in Europe. The main clinical features are nasal congestion, sore throat, dysphagia and epistaxis, due to a destructive mass involving the midline facial tissues. Pathologically, lymphoma cells exhibit angioinvasion, angiodestruction and coagulative necrosis. We report the case of a patient who presented with fever, dyspnea, nasal congestion, headache, distention of right nasal turbinates and exophytic lower leg ulcerating lesions. A CT scan of visceral scull demonstrated a filling mass of right frontal, ethmoidal and maxillary sinuses with erosion of the wall of right maxillary sinus and ventral portion of the diaphragm. A biopsy was performed in the skin lesion and showed an angioinvasive NK/T cell lymphoma CD56 negative with clonal rearrangement of the T-cell-receptor gamma gene. Up to our knowledge, this is a rare immunophenotype for NK/T-cell, 'nasal type,' lymphomas. However, the lymphoma may be classified as extranodal NK/T cell lymphoma, 'nasal type,' due to typical clinical presentation, radiologic findings and pathological characteristics of polymorphism, angioinvasion, angiodestruction and coagulative necrosis.

The anaplastic lymphoma kinase is an effective oncoantigen for lymphoma vaccination

An ideal vaccination strategy against tumors relies on specific antigens that are required for tumor maintenance. For lymphoma, vaccination with subject-specific immunoglobulin idiotypes has had the most promising results. Here we show that DNA vaccination with plasmids encoding portions of the cytoplasmic domain of anaplastic lymphoma kinase (ALK), which has been translocated in different fusion proteins necessary for the growth of anaplastic large cell lymphoma (ALCL), protects mice from local and systemic lymphoma growth. The protection is potent and long lasting and elicits ALK-specific interferon-gamma responses and CD8+ T cell-mediated cytotoxicity. A combination of chemotherapy and vaccination significantly enhanced the survival of mice challenged with ALK+ lymphomas. These findings indicate that ALK represents an ideal tumor antigen for vaccination-based therapies of ALCL and possibly other ALK+ human tumors.

Peripheral T-cell lymphoma in childhood: population-based experience in the United Kingdom over 20 years

BACKGROUND

Peripheral T-cell lymphomas (PTCL) are very rare in children and this has prevented assessment of best treatment and prognosis.

PROCEDURE

Registry-based experience in England, Scotland and Wales over a 20-year period was studied to address these shortfalls. Anaplastic large cell lymphoma and mycosis fungoides were excluded due to recent publications describing UK experience with these disorders.

RESULTS

Twenty-five cases were identified, comprising 1.6% of non-Hodgkin lymphoma (NHL) registrations; 17 (68%) children with PTCL-unspecified (PTCL-u), 3 (12%) with angiocentric PTCL, 3 (12%) with angioimmunoblastic PTCL, and 2 (8%) with subcutaneous panniculitis-like T-cell lymphoma. Eighteen children were male, with a male/female ratio of 2.6:1. Median age was 7 (range 1-14) years. Eleven children (44%) died and actuarial survival was 76% at 1 year, 64% at 3 years and 59% at 5 years. Treatments given were subdivided between group T (regimens for T NHL or acute lymphoblastic leukaemia) or group B (regimens for B NHL). Amongst the 17 children with PTCL-u, 9/12 children in group T survived compared with 1/5 group B.

CONCLUSIONS

The Children's Cancer and Leukaemia Group recommendation that children with PTCL-u receive group T therapy is supported by this series. The numbers of children with other types of PTCL were too small to allow conclusions on best therapy.

Results of a phase III clinical trial: CHOP versus CMED in peripheral T-cell lymphoma unspecified

We performed a controlled clinical trial to define the use of a brief therapy: CMED (cyclophosphamide, etoposide, methotrexate, and dexamethasone) compared with standard CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) in the treatment of peripheral T-cell lymphoma unspecific (PTCLu). The end point to the study was to assess efficacy, measured from complete response rate (CRR), progression-free survival (PFS), and overall survival in 217 previously untreated patients with PTCLu. In an intent-to treat analysis all patients were evaluable. CRR was 76% in CMED regimen and 57% in CHOP arm (P<0.05); actuarial curves at 10 years showed that PFS was 70% and 43%, respectively (P<0.01); overall survival was 60% and 34%, respectively (P<0.01). Adjuvant radiotherapy was employed in 48 cases (54% of patients who achieve CR in CMED arm) and 30 patients (47% of patients who achieve CR in CHOP arm). Acute toxicity was mild and well tolerated. Our results showed that the CMED regimen is feasible and effective in PTCLu.

The anaplastic lymphoma kinase in the pathogenesis of cancer

Tyrosine kinases are involved in the pathogenesis of most cancers. However, few tyrosine kinases have been shown to have a well-defined pathogenetic role in lymphomas. The anaplastic lymphoma kinase (ALK) is the oncogene of most anaplastic large cell lymphomas (ALCL), driving transformation through many molecular mechanisms. In this Review, we will analyse how translocations or deregulated expression of ALK contribute to oncogenesis and how recent genetic or pharmacological tools, aimed at neutralizing its activity, can represent the basis for the design of powerful combination therapies.

Blood and Marrow Transplant Clinical Trials Network State of the Science Symposium 2007

Outcomes of hematopoietic cell transplantation are steadily improving. New techniques have reduced transplant toxicities, and there are new sources of hematopoietic stem cells from unrelated donors. In June 2007 the Blood and Marrow Transplant Clinical Trials Network convened a State of the Science Symposium of more than 200 participants in Ann Arbor to identify the most compelling clinical research opportunities in the field. This report summarizes the symposium's discussions and identifies eleven high priority clinical trials that the network plans to pursue over the course of the next several years.

Amplification at 7q22 targets cyclin-dependent kinase 6 in T-cell lymphoma

Recurrent chromosomal aberrations in hematopoietic tumors target genes involved in pathogenesis. Their identification and functional characterization are therefore important for the establishment of rational therapies. Here, we investigated genomic amplification at 7q22 in the T-cell lymphoma cell line SU-DHL-1 belonging to the subtype of anaplastic large-cell lymphoma (ALCL). Cytogenetic analysis mapped this amplicon to 86-95 Mb. Copy-number determination quantified the amplification level at 5- to 6-fold. Expression analysis of genes located within this region identified cyclin-dependent kinase 6 (CDK6) as a potential amplification target. In comparison with control cell lines, SU-DHL-1 expressed considerably higher levels of CDK6. Functionally, SU-DHL-1 cells exhibited reduced sensitivity to rapamycin treatment, as indicated by cell growth and cell cycle analysis. Rapamycin reportedly inhibits degradation of the CDK inhibitor p27 with concomitant downregulation of cyclin D3, implying a proliferative advantage for CDK6 overexpression. Amplification of the CDK6 locus was analyzed in primary T-cell lymphoma samples and, while detected infrequently in those classified as ALCL (1%), was detected in 23% of peripheral T-cell lymphomas not otherwise specified. Taken together, analysis of the 7q22 amplicon identified CDK6 as an important cell cycle regulator in T-cell lymphomas, representing a novel potential target for rational therapy.

FDG-PET in T-cell and NK-cell neoplasms

BACKGROUND

A growing number of studies demonstrate the utility of (18)fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the management of malignant lymphoma. The results of FDG-PET, however, have not been studied extensively for T-cell and natural killer (NK)-cell neoplasms.

PATIENTS AND METHODS

We retrospectively evaluated pretreatment FDG-PET scans in 41 patients with T/NK-cell neoplasms diagnosed according to the World Health Organization (WHO) classification. Histological subtypes frequently included were peripheral T-cell lymphoma, unspecified (PTCLu, n = 11), extranodal NK/T-cell lymphoma, nasal type (ENKL, n = 8), primary cutaneous anaplastic large cell lymphoma (C-ALCL, n = 5), and angioimmunoblastic T-cell lymphoma (AILT, n = 4).

RESULTS

FDG-PET detected a lymphoma lesion in at least one site in 36 out of 41 patients. The positive rate was equally high in most histological subtypes except for cutaneous lymphomas: PTCLu 91%, ENKL 100%, C-ALCL 60%, AILT 100%. All the patients without an FDG-avid lesion had lesions restricted to skin. Among patients who had cutaneous lesions, only 50% had FDG-avid cutaneous lesions, all of which were tumorous. The positive rate of FDG-PET for bone marrow involvement was only 20%.

CONCLUSION

T/NK-cell neoplasms incorporated in this study were generally FDG-avid except for cutaneous lesions and bone marrow involvement.

Epidermotropic Precursor T-cell Lymphoma With Highly Aggressive Clinical Behavior Simulating Localized Pagetoid Reticulosis

We describe a 43-year-old patient with a solitary, eczematous plaque on his right nipple that had developed during the previous 6 weeks. Histopathology revealed a superficial band-like infiltrate of medium to large-sized pleomorphic lymphocytes with striking epidermotropism. The tumor cells expressed a T-phenotype (CD3+, CD20-) and were CD30-, CD4-, and CD8-negative. A diagnosis of localized pagetoid reticulosis (Woringer-Kolopp disease) with possible large cell transformation was proposed. A cervical lymph node excised 2 months later showed features of a highly aggressive blastoid precursor T-cell lymphoma. Reevaluation of the skin lesion and of a tonsil specimen previously interpreted as benign hyperplasia showed features consistent with those observed in the lymph node. The disease was rapidly progressive, and the patient died 15 months after the first skin biopsy. This case represents a unique cutaneous presentation of aggressive precursor lymphoma, showing the protean nature of lymphoproliferative disorders and the overlapping clinical and histopathologic features of different entities.

Molecular genetic analysis of haematological malignancies II: mature lymphoid neoplasms

Molecular genetic techniques have become an integral part of the diagnostic assessment for many lymphomas and other chronic lymphoid neoplasms. The demonstration of a clonal immunoglobulin or T cell receptor gene rearrangement offers a useful diagnostic tool in cases where the diagnosis is equivocal. Molecular genetic detection of other genomic rearrangements may not only assist with the diagnosis but can also provide important prognostic information. Many of these rearrangements can act as molecular markers for the detection of low levels of residual disease. In this review, we discuss the applications of molecular genetic analysis to the chronic lymphoid malignancies. The review concentrates on those disorders for which molecular genetic analysis can offer diagnostic and/or prognostic information.

Detection of NOTCH1 mutations in adult T-cell leukemia/lymphoma and peripheral T-cell lymphoma

We analyzed NOTCH1 gene mutation in 53 adults with mature T-cell leukemia/lymphoma: 21 patients with adult T-cell leukemia (ATL), 25 with T-cell non-Hodgkin's lymphoma (T-NHL), and 7 with T-cell prolymphocytic leukemia. We detected a nonsense mutation, C7249T (resulting in Q2417X, where X is a termination codon) in the PEST domain of NOTCH1 in an ATL patient and detected a 3-bp deletion (positions 7234-7236) that resulted in deletion of a proline codon at codon 2412 in the PEST domain of NOTCH1 in a patient with a T-NHL, peripheral T-cell lymphoma-unspecified (PTCL-u). We also analyzed the expression of NOTCH1 target genes (HES1, CCND1, and MYC), all of which were expressed in the sample of the PTCL-u patient with the NOTCH1 mutation, but found only MYC to be expressed in the sample from the ATL patient. These findings suggest that nonsense mutation in the PEST domain in the ATL case was associated with NOTCH1 signaling through a pathway different from that for T-cell acute lymphoblastic leukemia (T-ALL). Although NOTCH1 mutation occurs infrequently in mature T-cell leukemia/lymphoma, NOTCH1 may be involved in leukemogenesis associated with various forms of T-cell leukemia/lymphoma rather than only with T-ALL.

Treatment of non-Hodgkin's lymphoma: a look over the past decade

The past decade has seen enormous changes in our understanding of lymphomas with a better classification (World Heath Organization) and identification of better prognostic factors; however, important genetic prognostic factors have not been completely analyzed. The appearance of rituximab and other monoclonal antibodies has completely revolutionized the treatment of this disease. If monoclonal antibodies have activity when used alone, most patients experienced relapse after such a treatment, even after maintenance therapy. The combination of rituximab with chemotherapy has now been shown in several randomized studies to increase the response rate, decrease the relapse rate, and prolong progression-free survival and overall survival. Rituximab plus CHOP (cyclophosphamide/doxorubicin/prednisone/vincristine; R-CHOP) has become the standard for patients with diffuse large B-cell lymphoma. Rituximab chemotherapy, probably with the CHOP regimen, is slowly gaining importance as the standard for patients with follicular lymphoma. Although little is known for other indolent lymphomas and mantle cell lymphoma, progress has been made there, too. Several questions remain for future randomized studies to continue our search toward cure.

Interleukin-10 gene polymorphism influences the prognosis of T-cell non-Hodgkin lymphomas

Interleukin-10 (IL-10) is one of the cytokines implicated in the pathogenesis of diffuse large B-cell lymphoma (DLBCL) in which it acts as auto/paracrine growth factor for lymphoma growth. T-cell non-Hodgkin lymphoma (NHL) is a heterogeneous disease, the biological basis of which is not fully understood. Some evidence suggests that IL-10 might be associated with the progression of T-cell NHLs and that IL-10 may be involved in a rescue effect, protecting T cells from apoptotic cell death associated with upregulated bcl-2 expression. The current study evaluated the impact of IL-10 gene (IL10) polymorphism on the response to chemotherapy and survival in T-cell NHL. IL10 polymorphisms were determined in 108 patients with T-cell NHL. The response to chemotherapy was not dependent on IL10 polymorphism, while survival differed significantly according to IL10 polymorphism. The group with ATA haplotype showed superior overall survival (61.2 +/- 5.9% vs. 21.2 +/- 11.7%, P = 0.001) and failure-free survival (35.0 +/- 5.7% vs. 13.2 +/- 8.7%, P = 0.001) compared to those without ATA haplotype. The ATA haplotype was identified as a favourable prognostic factor compared to non-ATA haplotype (P = 0.037, hazard ratio 2.1), together with international prognostic index (IPI) in a multivariate model for overall survival. In conclusion, IL10 polymorphism may affect the survival of T-cell NHL patients.

Small Lymphoid Proliferations in Extranodal Locations

Context.—Low-grade non-Hodgkin lymphomas frequently involve extranodal sites including the gastrointestinal tract, skin, and lung, either selectively or as part of widespread dissemination. Differentiation from inflammatory or infectious conditions requires knowledge of specific histologic characteristics of the various entities as well as ancillary techniques.

Objective.—To describe the key features and provide diagnostic clues to the identification of specific extranodal low-grade lymphomas of T-cell and B-cell types including small lymphocytic lymphoma, follicular lymphoma, mantle cell lymphoma, extranodal marginal zone B-cell lymphomas of mucosal-associated lymphoid tissue, and hairy cell leukemia. Histologic and cytologic features are highlighted, as well as appropriate integration of results of ancillary diagnostic studies including flow cytometry, immunohistochemistry, molecular features, and cytogenetics.

Data Sources.—The published literature as well as personal experience from a specialized hematopathology practice at a large university medical center.

Conclusions.—Correct identification of extranodal low-grade lymphomas and differentiation from hyperplastic and inflammatory or infectious processes require the ability to distinguish each of the specific entities discussed. Ancillary studies are often indispensable in reaching a correct diagnosis.

Gene expression analysis of peripheral T cell lymphoma, unspecified, reveals distinct profiles and new potential therapeutic targets

Peripheral T cell lymphoma, unspecified (PTCL/U), the most common form of PTCL, displays heterogeneous morphology and phenotype, poor response to treatment, and poor prognosis. We demonstrate that PTCL/U shows a gene expression profile clearly distinct from that of normal T cells. Comparison with the profiles of purified T cell subpopulations (CD4+, CD8+, resting [HLA-DR-], and activated [HLA-DR+]) reveals that PTCLs/U are most closely related to activated peripheral T lymphocytes, either CD4+ or CD8+. Interestingly, the global gene expression profile cannot be surrogated by routine CD4/CD8 immunohistochemistry. When compared with normal T cells, PTCLs/U display deregulation of functional programs often involved in tumorigenesis (e.g., apoptosis, proliferation, cell adhesion, and matrix remodeling). Products of deregulated genes can be detected in PTCLs/U by immunohistochemistry with an ectopic, paraphysiologic, or stromal location. PTCLs/U aberrantly express, among others, PDGFRalpha, a tyrosine-kinase receptor, whose deregulation is often related to a malignant phenotype. Notably, both phosphorylation of PDGFRalpha and sensitivity of cultured PTCL cells to imatinib (as well as to an inhibitor of histone deacetylase) were found. These results, which might be extended to other more rare PTCL categories, provide insight into tumor pathogenesis and clinical management of PTCL/U.

Therapy of Peripheral T/NK Neoplasms

The mature T/natural killer (NK) lymphoma/leukemias represent 5–15% of all non-Hodgkin lymphoma. These diseases have a geographic variation, with more nodal disease in North America and Europe, including peripheral T cell lymphomas, unspecified, anaplastic large cell lymphoma, and angioimmunoblastic T cell lymphoma; and more extranodal disease in Asia due to Epstein-Barr virus–related nasal NK/T lymphoma and human T-cell leukemia virus (HTLV)-1–associated adult T cell leukemia/lymphoma. The prognosis in most peripheral T/NK neoplasms is poor, with 5-year survival less than 30%. Progress has been slow due to the rarity of the diseases, geographic variation, relative chemoresistance, and lack of randomized trials. There is no consensus about optimal therapy in T/NK neoplasms, and recommendations are based on anecdotal reports, small series, and phase II trials. In this review, topics include the question of CHOP as standard therapy, prognostic factors, disease-adapted therapy, novel approaches, monoclonal antibody therapy, and stem cell transplantation.