Clonal KEAP1 mutations with loss of heterozygosity share reduced immunotherapy efficacy and low immune cell infiltration in lung adenocarcinoma.

BACKGROUND: KEAP1 mutations have been associated with reduced survival in lung adenocarcinoma (LUAD) patients treated with immune checkpoint inhibitors (ICIs), particularly in the presence of STK11/KRAS alterations. We hypothesized that, beyond co-occurring genomic events, clonality prediction may help identify deleterious KEAP1 mutations and their counterparts with retained sensitivity to ICIs. PATIENTS AND METHODS: Beta-binomial modelling of sequencing read counts was used to infer KEAP1 clonal inactivation by combined somatic mutation and loss of heterozygosity (KEAP1 C-LOH) versus partial inactivation [KEAP1 clonal diploid-subclonal (KEAP1 CD-SC)] in the Memorial Sloan Kettering Cancer Center (MSK) MetTropism cohort (N = 2550). Clonality/LOH prediction was compared to a streamlined clinical classifier that relies on variant allele frequencies (VAFs) and tumor purity (TP) (VAF/TP ratio). The impact of this classification on survival outcomes was tested in two independent cohorts of LUAD patients treated with immunotherapy (MSK/Rome N = 237; DFCI N = 461). Immune-related features were studied by exploiting RNA-sequencing data (TCGA) and multiplexed immunofluorescence (DFCI mIF cohort). RESULTS: Clonality/LOH inference in the MSK MetTropism cohort overlapped with a clinical classification model defined by the VAF/TP ratio. In the ICI-treated MSK/Rome discovery cohort, predicted KEAP1 C-LOH mutations were associated with shorter progression-free survival (PFS) and overall survival (OS) compared to KEAP1 wild-type cases (PFS log-rank P = 0.001; OS log-rank P < 0.001). Similar results were obtained in the DFCI validation cohort (PFS log-rank P = 0.006; OS log-rank P = 0.014). In both cohorts, we did not observe any significant difference in survival outcomes when comparing KEAP1 CD-SC and wild-type tumors. Immune deconvolution and multiplexed immunofluorescence revealed that KEAP1 C-LOH and KEAP1 CD-SC differed for immune-related features. CONCLUSIONS: KEAP1 C-LOH mutations are associated with an immune-excluded phenotype and worse clinical outcomes among advanced LUAD patients treated with ICIs. By contrast, survival outcomes of patients whose tumors harbored KEAP1 CD-SC mutations were similar to those with KEAP1 wild-type LUADs.

KEAP1-driven co-mutations in lung adenocarcinoma unresponsive to immunotherapy despite high tumor mutational burden.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have demonstrated significant overall survival (OS) benefit in lung adenocarcinoma (LUAD). Nevertheless, a remarkable interpatient heterogeneity characterizes immunotherapy efficacy, regardless of programmed death-ligand 1 (PD-L1) expression and tumor mutational burden (TMB). KEAP1 mutations are associated with shorter survival in LUAD patients receiving chemotherapy. We hypothesized that the pattern of KEAP1 co-mutations and mutual exclusivity may identify LUAD patients unresponsive to immunotherapy. PATIENTS AND METHODS: KEAP1 mutational co-occurrences and somatic interactions were studied in the whole MSKCC LUAD dataset. The impact of coexisting alterations on survival outcomes in ICI-treated LUAD patients was verified in the randomized phase II/III POPLAR/OAK trials (blood-based sequencing, bNGS cohort, N = 253). Three tissue-based sequencing studies (Rome, MSKCC and DFCI) were used for independent validation (tNGS cohort, N = 289). Immunogenomic features were analyzed using The Cancer Genome Atlas (TCGA) LUAD study. RESULTS: On the basis of KEAP1 mutational co-occurrences, we identified four genes potentially associated with reduced efficacy of immunotherapy (KEAP1, PBRM1, SMARCA4 and STK11). Independent of the nature of co-occurring alterations, tumors with coexisting mutations (CoMut) had inferior survival as compared with single-mutant (SM) and wild-type (WT) tumors (bNGS cohort: CoMut versus SM log-rank P = 0.048, CoMut versus WT log-rank P < 0.001; tNGS cohort: CoMut versus SM log-rank P = 0.037, CoMut versus WT log-rank P = 0.006). The CoMut subset harbored higher TMB than the WT disease and the adverse significance of coexisting alterations was maintained in LUAD with high TMB. Significant immunogenomic differences were observed between the CoMut and WT groups in terms of core immune signatures, T-cell receptor repertoire, T helper cell signatures and immunomodulatory genes. CONCLUSIONS: This study indicates that coexisting alterations in a limited set of genes characterize a subset of LUAD unresponsive to immunotherapy and with high TMB. An immune-cold microenvironment may account for the clinical course of the disease.

Expression of TP53 mutation-associated microRNAs predicts clinical outcome in head and neck squamous cell carcinoma patients.

BACKGROUND: TP53 mutation is associated with decreased survival rate in head and neck squamous cell carcinoma (HNSCC) patients. We set out to identify microRNAs (miRNAs) whose expression associates with TP53 mutation and survival in HNSCC. PATIENTS AND METHODS: We analyzed TP53 status by direct sequencing of exons 2 through 11 of a prospective series of 121 HNSCC samples and assessed its association with outcome in 109 followed-up patients. We carried out miRNA expression profiling on 121 HNSCC samples and 66 normal counterparts. miRNA associations with TP53 mutations and outcome were evaluated. RESULTS: A TP53 mutation was present in 58% of the tumors and TP53 mutations were significantly associated with a shorter recurrence-free survival. This association was stronger in the clinical subgroup of patients subjected to adjuvant therapy after surgery. The expression of 49 miRNAs was significantly associated with TP53 status. Among these 49, we identified a group of 12 miRNAs whose expression correlates with recurrence-free survival and a group of 4 miRNAs that correlates with cancer-specific survival. The two groups share three miRNAs. Importantly, miRNAs that correlate with survival are independent prognostic factors either when considered individually or as signatures. CONCLUSIONS: miRNAs expression associates with TP53 status and with reduced survival after surgical treatment of squamous cell carcinoma of the head and neck.

Primary cutaneous B-cell lymphoma is associated with somatically hypermutated immunoglobulin variable genes and frequent use of VH1-69 and VH4-59 segments.

BACKGROUND: Accurate assessment of the somatic mutational status of clonal immunoglobulin variable region (IgV) genes is relevant in elucidating tumour cell origin in B-cell lymphoma; virgin B cells bear unmutated IgV genes, while germinal centre and postfollicular B cells carry mutated IgV genes. Furthermore, biases in the IgV repertoire and distribution pattern of somatic mutations indicate a possible antigen role in the pathogenesis of B-cell malignancies. OBJECTIVES: This work investigates the cellular origin and antigenic selection in primary cutaneous B-cell lymphoma (PCBCL). METHODS: We analysed the nucleotide sequence of clonal IgV heavy-chain gene (IgVH) rearrangements in 51 cases of PCBCL (25 follicle centre, 19 marginal zone and seven diffuse large B-cell lymphoma, leg-type) and compared IgVH sequences with their closest germline segment in the GenBank database. Molecular data were then correlated with histopathological features. RESULTS: We showed that all but one of the 51 IgVH sequences analysed exhibited extensive somatic hypermutations. The detected mutation rate ranged from 1.6% to 21%, with a median rate of 9.8% and was independent of PCBCL histotype. Calculation of antigen-selection pressure showed that 39% of the mutated IgVH genes displayed a number of replacement mutations and silent mutations in a pattern consistent with antigenic selection. Furthermore, two segments, VH1-69 (12%) and VH4-59 (14%), were preferentially used in our case series. CONCLUSIONS: Data indicate that neoplastic B cells of PBCBL have experienced germinal centre reaction and also suggest that the involvement of IgVH genes is not entirely random in PCBCL and that common antigen epitopes could be pathologically relevant in cutaneous lymphomagenesis.

Regulation of TCL1 expression in B- and T-cell lymphomas and reactive lymphoid tissues.

Chromosomal rearrangements observed in T-cell prolymphocytic leukemia involve the translocation of one T-cell receptor gene to either chromosome 14q32 or Xq28, deregulating the expression of cellular protooncogenes of unknown function, such as TCL1 or its homologue, MTCP1. In the human hematopoietic system, TCL1 expression is predominantly observed in developing B lymphocytes, whereas its overexpression in T cells causes mature T-cell proliferation in transgenic mice. In this study, using a newly generated monoclonal antibody against recombinant TCL1 protein, we extended our analysis mainly by immunohistochemistry and also by fluorescence-activated cell sorting and Western blot to a large tumor lymphoma data bank including 194 cases of lymphoproliferative disorders of B- and T-cell origin as well as reactive lymphoid tissues. The results obtained show that in reactive lymphoid tissues, TCL1 is strongly expressed by a subset of mantle zone B lymphocytes and is expressed to a lesser extent by follicle center cells and by scattered interfollicular small lymphocytes. In B-cell neoplasia, TCL1 was expressed in the majority of the cases, including lymphoblastic lymphoma, chronic lymphocytic leukemia, mantle cell lymphoma, follicular lymphoma, Burkitt lymphoma, diffuse large B-cell lymphoma (60%), and primary cutaneous B cell lymphoma (55%). TCL1 expression was observed in both the cytoplasmic and nuclear compartments, as confirmed by Western blot analysis. Conversely, TCL1 was not expressed in Hodgkin/Reed-Sternberg cells, multiple myelomas, marginal zone B-cell lymphomas, CD30+ anaplastic large cell lymphoma, lymphoblastic T-cell lymphoma, peripheral T-cell lymphoma, and mycosis fungoides. These data indicate that TCL1 is expressed in more differentiated B cells, under both reactive and neoplastic conditions, from antigen committed B cells and in germinal center B cells and is down-regulated in the latest stage of B-cell differentiation.

Neutropenic enterocolitis in patients with acute leukemia: prognostic significance of bowel wall thickening detected by ultrasonography.

PURPOSE: Neutropenic enterocolitis (NE) is a severe complication of intensive chemotherapy and is barely identifiable by clinical signs alone. Ultrasonography (US) supports the diagnosis of NE by showing pathologic thickening of the bowel wall. The aim of this study was to evaluate the prognostic value of the degree of mural thickening evaluated by US in patients with clinically suspected NE. PATIENTS AND METHODS: Neutropenic patients with fever, diarrhea, and abdominal pain after intensive chemotherapy for hematologic malignancies were studied with abdominal US. We evaluated the degree of bowel wall thickening detected by US and its correlation with the duration of the clinical syndrome as well as NE-related mortality. RESULTS: Eighty-eight (6%) of 1,450 consecutive patients treated for leukemia had clinical signs of NE. In 44 (50%) of 88 patients, US revealed pathologic wall thickening (mean +/- SD, 10.2 +/- 2.9 mm; range, 6 to 18). The mean duration of symptoms was significantly longer in this group (7.9 days) than among patients without mural thickening (3.8 days, P <.0001), and the NE-related mortality rate was higher (29.5% v 0%, P <.001). Patients with bowel wall thickness of more than 10 mm had a significantly higher mortality rate (60%) than did those with bowel wall thickness < or = 10 mm (4.2%, P <.001). CONCLUSION: Symptomatic patients with sonographically detected bowel wall thickening have a poor prognosis compared with patients without this finding. In addition, mural thickness of more than 10 mm is associated with poorer outcome among patients with NE.

Epstein-Barr virus infection is predictive of CNS involvement in systemic AIDS-related non-Hodgkin's lymphomas.

PURPOSE: This study aimed at correlating Epstein-Barr virus (EBV) infection of systemic AIDS-related non-Hodgkin lymphomas (AIDS-NHL) with the development of a CNS localization of the tumor. PATIENTS AND METHODS: Demographic, epidemiologic, clinical, histologic, and virologic features were collected for all systemic AIDS-NHL patients included in the study (n = 50). Pathologic specimens were classified according to the working formulation for NHL and the Revised European-American Lymphoma classification. EBV infection in tumor tissue samples was studied by EBV small encoded RNA in situ hybridization; EBV-DNA detection in CSF was carried out by nested polymerase chain reaction using Epstein-Barr nuclear antigen-1-specific primers. In addition, selected EBV-positive lymphomas were subjected to a detailed characterization of EBV molecular heterogeneity. RESULTS: Eleven patients had a CNS involvement at some point during their clinical history (four at diagnosis and seven at relapse). Thirty patients (11 with CNS involvement and 19 without) harbored EBV infection of the tumor. Sensitivity, specificity, and positive and negative predictive values of EBV-DNA detection in CSF for CNS involvement by lymphoma were 90%, 100%, 100%, and 97.6%, respectively. Factors significantly predictive of CNS involvement were EBV infection of the tumor (P=.003), an extranodal disease at diagnosis other than CNS (P=.006), and a non-CNS relapse (P=.01). In four cases of CNS involvement, EBV-DNA in CSF preceded any other sign of disease by a mean of 35 days. CONCLUSION: These results show that EBV infection of the tumor clone significantly increases the risk of CNS involvement by systemic AIDS-NHL, without regard of specific molecular features. The detection of EBV-DNA in the CSF of AIDS-NHL patients may select cases with higher risk of CNS involvement and, therefore, may prove useful in the therapeutic stratification of these tumors.

Early autologous stem-cell transplantation versus conventional chemotherapy as front-line therapy in high-risk, aggressive non-Hodgkin's lymphoma: an Italian multicenter randomized trial.

PURPOSE: To evaluate the role of early intensification with high-dose therapy (HDT) and autologous stem-cell transplantation (ASCT) as front-line chemotherapy for patients with high-risk, histologically aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: We planned a multicenter, randomized trial to compare a conventional chemotherapy regimen of methotrexate with leucovorin rescue, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B; arm A) with an abbreviated regimen of MACOP-B (8 weeks) followed by HDT and ASCT (arm B) for intermediate-high-risk/high-risk patients (according to the age-adjusted International Prognostic Index). From September 1994 to April 1998, 150 patients with aggressive lymphoma were enrolled onto the trial. Seventy-five patients were randomly assigned to arm A and 75 patients were randomly assigned to arm B. In both arms, involved-field radiation therapy (36 Gy) was delivered to the site of bulky disease. RESULTS: The rate of complete response was 68% in arm A and 76% in arm B (P = not significant [NS]). Three toxic deaths (4%) occurred in arm B and one (1%) occurred in arm A (P = NS). In arm B, 30 patients (40%) did not undergo HDT and ASCT. According to the intention-to-treat analysis at a median follow-up of 24 months, 5-year overall survival probability in arms A and B was 65% and 64% (P =.95), 5-year progression-free survival was 49% and 61% (P =.21), and 5-year relapse-free survival was 65% and 77% (P =.22), respectively. CONCLUSION: Abbreviated chemotherapy followed by intensification with HDT-ASCT is not superior to conventional chemotherapy in patients with high-risk, aggressive NHL. Additional randomized trials will clarify whether HDT-ASCT as front-line therapy after a complete course of conventional chemotherapy improves survival in this group of patients.

Surgical approach to isolated mediastinal lymphoma.

With the aim of assessing the role of surgery in the management of isolated mediastinal lymphoma, we have reviewed the data of 123 operations performed on 102 patients (64 with Hodgkin's disease and 38 with non-Hodgkin's lymphoma). One death and four major complications occurred in these patients. Macroscopically radical resection was performed in 14 patients who are free of disease after 1 to 14 years. Debulking resection was performed in five patients: Three are alive after 5 to 11 years and two died after 36 and 40 months. Ten patients (seven with non-Hodgkin's lymphoma and three with Hodgkin's disease) had residual mediastinal masses of more than 2 cm after chemotherapy; to assess the nature of the lesion (fibrosis or residual disease), we subjected these patients to surgical restaging of the mediastinum: Results were negative in seven and positive in three. We conclude that open biopsy is indispensable to obtain good tissue specimens suitable for histologic and immunohistochemical assessment. Biopsy must be performed as a major surgical procedure to avoid reoperation: Mediastinoscopy and sternal splitting incisions proved the most reliable approaches. Locally radical or debulking resection might be considered in selected cases to enhance long-term results.

The prognostic implication of thymoma histologic subtyping. A study of 80 consecutive cases.

In this study the authors have investigated the clinicopathologic correlations in 80 consecutive cases of thymoma in order to establish the clinical usefulness of histologic subtyping of these tumours. All cases were histologically examined and classified according to Salyer and Eggleston and to Marino and Müller-Hermelink classifications. Therefore, thymomas were subtyped as predominantly lymphocytic, mixed and predominantly epithelial and cortical, mixed and medullary, respectively. The frequency of the different histologic subtypes was determined, and histologic findings were related to patients' age, surgical stage, and survival. Through the application of Salyer and Eggleston classification, the three histologic subtypes did not correlate with patients' ages at time of diagnosis, surgical stage as determined by local infiltration, and prognosis as determined by survival curves. On the contrary, when Marino and Müller-Hermelink classification was applied, statistically significant relationships between histologic results and age, surgical stage, and prognosis were demonstrated. These results and their implications are discussed, with special reference to the important problem of histogenesis of thymomas and of their clinicopathologic staging.

Hodgkin/Reed-Sternberg cells and Hodgkin's disease in patients with B-cell chronic lymphocytic leukaemia: an immunohistological, molecular and clinical study of four cases suggesting a heterogeneous pathogenetic background.

We report the immunohistological, molecular and clinical findings in four patients affected by B-cell chronic lymphocytic leukaemia (CLL) who developed "Richter's syndrome with Hodgkin's disease (HD) features" or "CLL with Hodgkin's transformation", all characterised by the presence of typical Hodgkin/Reed-Sternberg (H/RS) cells in lymph node biopsies. In three cases the nodal involvement by CLL was demonstrated both by the presence of a predominant background of CD5/CD19/CD23+ small lymphocytes and an IgH monoclonal rearrangement revealed by PCR analysis. Conversely, in the remaining case there was neither immunohistological nor molecular evidence of lymph node involvement by CLL. In all four cases H/RS cells were Epstein-Barr virus (EBV) latent membrane protein (LMP-1) positive. These findings suggest that the presence of H/RS cells in the first three patients, who had CLL/HD nodal involvement, might be related to transformation or clonal evolution of CLL cells in H/RS cells, which is in keeping with use of the term "CLL with Hodgkin's transformation". In the fourth case a de novo HD may be postulated, representing a second malignancy presumably not clonally related to CLL. In all cases a key pathogenetic role of EBV is suggested by the expression of LMP-1 in H/RS cells. Our findings indicate that the presence of typical H/RS cells in lymph node biopsies in CLL patients may reflect a heterogeneous pathogenetic background. The different clinico-pathologic settings should be taken into consideration because of their possible implications for patients' treatment and prognosis.

Diagnostic relevance of peripheral blood immunocytochemistry in hairy cell leukaemia.

AIMS--(1) To assess the diagnostic relevance of peripheral blood immunocytochemistry in hairy cell leukaemia (HCL); (2) to compare the immunostaining of bone marrow biopsy specimens with bone marrow and peripheral blood cytospins; (3) to evaluate the sensitivity of the different markers used; (4) to identify the ultrastructural localisation of DBA.44 in HCL variant. METHODS--Immunoenzymatic staining procedures, immunoperoxidase and immunoalkaline phosphatase, were used with a panel of monoclonal antibodies directed to HCL associated antigens. Ultrastructural immunostaining was performed using colloidal gold conjugated antibodies. RESULTS--HCL showed strong cytoplasmic reactivity for CD22, CD25, CD103, DBA.44, kappa, or lambda light chains. Peripheral blood diagnostic hairy cells were found in all the cases with absolute counts ranging from 0.11 x 10(9)/l up to 6.4 x 10(9)/l and values increasing with the size of the spleen. A median of 36.5% of leukaemic cells was found in bone marrow aspirates and 70% in bone marrow trephine specimens. The monoclonal antibodies CD22 and DBA.44 showed the highest and the lowest percentage of positive hairy cells, respectively; this difference was statistically significant (p = 0.0025). Ultrastructural immunolabelling with DBA.44 showed a cytoplasmic membrane localisation of the antigen in one case of HCL variant. CONCLUSIONS--(1) Immunocytochemistry is a useful technique which enhances the accuracy of diagnosis in HCL; (2) peripheral blood immunocytochemistry is recommended because it highlights hairy cells in all cases; (3) CD22 appears to be the most sensitive of the markers tested; (4) ultrastructural analysis is a useful tool in selected cases of HCL variant.

"Composite" lymphoma, lymphoplasmacytoid and diffuse large B-cell lymphoma of the spleen: molecular-genetic evidence of a common clonal origin.

We describe here the first well-characterized case of "composite" lymphoma of the spleen in which the two components were a low-grade and a high-grade B-cell non-Hodgkin's lymphomas. The patient was an elderly man with prominent splenomegaly and multiple hypoechogenic lesions of the spleen. A splenectomy was performed, and the macroscopic and histological findings showed the simultaneous presence of a "low-grade" B-cell lymphoma, lymphoplasmacytoid (immunocytoma) and a "high-grade" B-cell lymphoma (immunoblastic), which were spatially separated. The two lesions expressed the same immunoglobulin light chain (lambda), but the Southern blot analysis showed different patterns of immunoglobulin heavy chain (IgH) clonal rearrangement. PCR analysis followed by direct sequencing of the IgH-amplified rearrangement products provided molecular-genetic evidence that the two components of the composite lymphoma had the same clonal origin. Since both EBV LMP-1 and p53 were negative by immunohistochemistry, it is unlikely that EBV and p53 were involved in the neoplastic progression in this case. PCR analysis and direct sequencing of IgH-amplified rearrangement products are useful tools to investigate clonality in cases in which Southern blot analysis cannot be performed or does not provide conclusive findings.

True thymic hyperplasia: a clinicopathological study.

In this report, we describe the clinicopathological features of 4 patients with true thymic hyperplasia. This controversial thymic lesion has only recently been defined as a variable, often massive enlargement of the thymus characterized by a nearly normal microscopic structure. Our study of 4 patients and review of the literature indicate that true thymic hyperplasia has a well-defined clinicopathological profile: prevalence in children or young male patients, absence of associated autoimmune diseases, and often presence of respiratory distress or peripheral blood lymphocytosis, or both. True thymic hyperplasia should be considered in the differential diagnosis of anterior mediastinal masses in children and young adolescents.

Diagnostic imaging and surgical treatment of dumbbell tumors of the mediastinum.

We describe the diagnostic procedures and surgical approaches employed in 5 patients with dumbbell tumors of the mediastinum. Magnetic resonance imaging accurately described the existence and longitudinal extension of the intraspinal component of the tumor and assisted in choosing the appropriate surgical approach. Both the intrathoracic and intraspinal components of the tumor were resected at one time by a thoracic and neurosurgical team. We employed the Grillo technique three times and a separate laminectomy and thoracotomy approach. Magnetic resonance imaging proved the most useful diagnostic technique for suspected dumbbell mediastinal tumors. In our experience, the extended thoracotomy proposed by Grillo and co-workers worked well for small tumors involving only one foramen in which the intraspinal extension was limited to 2 to 3 cm, and when no more than two laminectomies were required. On the other hand, thoracotomy and a longitudinal paravertebral incision are preferable for larger tumors (more than 4 cm) involving more than one foramen in which the intraspinal extension exceeds 2 to 3 cm, for tumors requiring multiple laminectomy, and when bony infiltration is present.

Comparative merits of thoracoscopy, mediastinoscopy, and mediastinotomy for mediastinal biopsy.

Between April 1992 and April 1993, we performed fifty-four mediastinal biopsies in 51 patients with a mediastinal mass. Nine of these had lung cancer with mediastinal lymphadenopathy, and the remaining 42 had various primary mediastinal lesions. We have performed twenty video-assisted thoracic surgical procedure, twenty-six mediastinoscopies, and eight anterior mediastinotomies. In 3 patients the diagnosis was not obtained by mediastinoscopy, and video-assisted thoracoscopy was performed. We conclude that mediastinoscopy is indicated for the majority of lesions involving the peritracheal space. Restaging of lymphoma and highly infiltrative lesions are better managed by video-assisted thoracic surgery. Anterior mediastinotomy is indicated when feasible under local anesthesia for tumors infiltrating the anterior chest wall. In all other cases video-assisted thoracic surgery is preferable because it allows removal of large tissue biopsy specimens and even resection with wide surgical exposure and low operative trauma.

Multimodality treatment of thymoma: a prospective study.

BACKGROUND: Thymomas are a heterogeneous group of tumors. Treatment of invasive lesions is not well standardized. The aim of this study is to propose a clinicopathologically based protocol for multimodality therapy. METHODS: Between 1965 and 1988, we operated on 83 patients with thymoma who did not receive standardized adjuvant therapy. In 1989, on the basis of the retrospective analysis of the data, we started a multimodality therapy protocol and used it for 65 patients. Twelve patients had medullary thymoma (11 stage I and 1 stage II), 13 had mixed type (6 stage I and 7 stage II), and 40 had cortical thymoma (4 stage I, 11 stage II, 12 stage III, and 13 stage IV). We considered three groups. Group I (n = 18 patients), benign thymoma, included stage I and II medullary and stage I mixed thymomas; radical resection with no adjuvant therapy was performed. Group II (n = 22), invasive thymoma, included stage I and II cortical and stage II mixed thymomas; postoperative chemotherapy plus radiotherapy was always administered. Group III (n = 25), malignant thymoma, comprised stage III and IV cortical thymomas and stage III mixed thymomas; resectable stage III lesions were removed, and highly invasive stage III and stage IV lesions underwent biopsy, neoadjuvant chemotherapy, and surgical resection; postoperative chemotherapy and radiotherapy was administered to all patients. RESULTS: The 8-year survival rate for patients in stages I, II, III, and IV was 95%, 100%, 92%, and 68%, respectively. Patients with medullary thymoma had a 92% 8-year survival rate; those with mixed type, 100%; and those with cortical thymoma, 85%. Group I had an 8-year survival rate of 94%; group II, 100%; and group III, 76%. Survival was compared with that of patients operated on before 1989: differences were not significant for group I; survival improved in group II (100% versus 81%; p = not significant); and group III showed significant improvement (76% versus 43%; p < 0.049). CONCLUSIONS: Multimodality treatment with neoadjuvant chemotherapy and adjuvant chemotherapy plus radiotherapy may improve the results of radical resection and the survival of patients with invasive and malignant thymoma.

Analysis of prognostic factors and clinicopathological staging of thymoma.

The prognostic value of four clinical variables (age and sex of patients, association with myasthenia gravis, and clinical stage) and histological type was analyzed in 83 consecutive patients with thymoma, histologically classified as cortical, medullary, and mixed. Age, sex, and association with myasthenia gravis did not prove to represent significant prognostic factors; clinical stage and histological type, on the contrary, had a highly significant prognostic value (p less than 0.001). A model of clinicopathological staging, based on both clinical stage and histological type, in which three major prognostic groups are considered is proposed. The degree of significance of this model is higher (p less than 0.0001) than that of clinical stage and histological type considered individually; its validity is further supported by the results of multivariate analysis according to the Cox regression model (p = 0.0001). We think it represents a prognostically valuable approach to the problem of management of thymoma.

Prognostic value of the histologic classification of peripheral T-cell lymphoma: a clinico-pathologic study of 71 HTLV-1 negative cases.

The histologic and clinical features of 71 cases of peripheral T-cell lymphoma (PTCL) have been studied. All patients were HTLV-1 negative. The T-cell phenotype was demonstrated by immunohistochemistry on cryostat sections (41 cases) and paraffin-embedded sections (30 cases). All cases were histologically classified according to the updated Kiel classification of non-Hodgkin's lymphoma (low and high-grade) and according to a Working Formulation (WF)-based classification (predominantly small cells, mixed small and large cells, and predominantly large cells). Most cases were in the high-grade group according to both classifications. The prognostic value of these two classifications was comparatively assessed. The analysis of the actuarial survival curves showed that, by using the updated Kiel classification, low-grade PTCL had a survival probability higher than high-grade PTCL although the difference was not statistically significant. Similar results were obtained when the WF-based classification was applied: furthermore, actuarial survival curves of mixed small and large cell PTCL, and of large cell PTCL were rather similar, thus indicating that differentiating these two categories has a limited prognostic value.

Detection of TT virus in lymph node biopsies of B-cell lymphoma and Hodgkin's disease, and its association with EBV infection.

Human TT virus (TTV) recently isolated from the serum of a patient with post-transfusion hepatitis does seem to have only hepatopathic effect. The virus can also infect the serum, peripheral blood mononuclear cells (PBMC) and bone marrow cells (BMC ). Additional evidence has indicated that TTV is also present in the serum of people with hematopoietic malignancies. A significant increase in the incidence of lymphoma has recently been observed worldwide. We have investigated the presence of TTV DNA in lymph node biopsies of Italian patients affected with the most common lymphoma types in Western Countries: follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) and nodular sclerosis Hodgkin's disease (NS-HD). The possible role of a co-infection with Epstein-Barr virus (EBV) has also been investigated. DNA was extracted from 73 paraffin-embedded and 38 snap-frozen tissue specimens. From these, only 67 samples (29 paraffin-embedded and 38 snap-frozen tissues) from a total of 56 patients, were suitable for PCR analysis. TTV and EBV were detected by PCR using primers from two different conserved region in TTV and EBV genomes respectively. TTV DNA was detected in 30.0-50.0% of FL, 30.8% of DLBCL and 30.0-50.0% of NS-HD cases, depending on the primers used. All cases of non-specific reactive lymphoid hyperplasia (RLH), used as a putative control, were negative. The two major TTV genotypes circulating in Italy (G1 and G2) were detected in the analysed lymphoid neoplasms. EBV DNA was detected in 40.0% of FL, in 72.7%of DLBCL, in 80.0% of SN-HD and in 40.0% of RLH cases. EBV co-infection was found in 90% of TTV positive cases. The in situ hybridization assay was performed in TTV positive frozen samples. The significant prevalence of TTV DNA in lymphocytes circulating in the lymph nodes of both B-cell lymphomas and HD reported herewith suggests an implication of TTV infection in the development of these lymphoproliferative disorders.