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.

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.

miR-204 targets Bcl-2 expression and enhances responsiveness of gastric cancer

Micro RNAs (miRs) are small non-coding RNAs aberrantly expressed in human tumors. Here, we aim to identify miRs whose deregulated expression leads to the activation of oncogenic pathways in human gastric cancers (GCs). Thirty nine out of 123 tumoral and matched uninvolved peritumoral gastric specimens from three independent European subsets of patients were analyzed for the expression of 851 human miRs using Agilent Platform. The remaining 84 samples were used to validate miRs differentially expressed between tumoral and matched peritumoral specimens by qPCR. miR-204 falls into a group of eight miRs differentially expressed between tumoral and peritumoral samples. Downregulation of miR-204 has prognostic value and correlates with increased staining of Bcl-2 protein in tumoral specimens. Ectopic expression of miR-204 inhibited colony forming ability, migration and tumor engraftment of GC cells. miR-204 targeted Bcl-2 messenger RNA and increased responsiveness of GC cells to 5-fluorouracil and oxaliplatin treatment. Ectopic expression of Bcl-2 protein counteracted miR-204 pro-apoptotic activity in response to 5-fluorouracil. Altogether, these findings suggest that modulation of aberrant expression of miR-204, which in turn releases oncogenic Bcl-2 protein activity might hold promise for preventive and therapeutic strategies of GC.

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.

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.

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.

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.

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.

Melphalan treatment in patients with myelofibrosis with myeloid metaplasia

Between January 1985 and December 1992, 104 consecutive patients with symptomatic myelofibrosis with myeloid metaplasia (MMM) [splenic enlargement >5 cm and/or transfusional requirement or Hb < 10 g/dl and/or white blood cell (WBC) count >20 x 10(9)/l and/or platelets >1.0 x 10(9)/l] received low-dose Melphalan (2.5 mg/3 times/week) to evaluate the efficacy and toxicity of this approach. Among 99 evaluable patients, 66 (66.7%) achieved a response after a median time of 6.7 months: 26 (26.3%) had a normalization of all clinical and haematological parameters (complete response, CR) and 40 (40.4%) showed an improvement >50% (partial response, PR). Thirty-three patients (33.3%) were resistant. Reversible haematological toxicity was the most common complication. Median durations of CR and PR were 28.4 and 26 months respectively: median survival of CR + PR patients was 71.2 months (95%CI: 33.8-108.7) versus 36.5 months (95%CI: 24.5-48.5) for the non-responders (log-rank test, P =0.002). In the multivariate analysis, the following variables were significantly associated with a shorter survival: anaemia [hazard risk (HR) = 2.7], WBC count >20 x 10(9)/l (HR = 2.4) and not achieving any type of response, either partial or complete (HR = 3.9). In conclusion, Melphalan could be a promising first-line option for MMM patients with clinical or haematological symptoms requiring treatment.

The role of high resolution pulsed and color Doppler ultrasound in the differential diagnosis of benign and malignant lymphadenopathy: results of multivariate analysis

BACKGROUND

The role of high resolution pulsed and color Doppler ultrasound in the differential diagnosis of benign and malignant lymphadenopathy is still unclear.

METHODS

High resolution pulsed and color Doppler ultrasound was used prospectively to investigate superficial lymph node enlargement in 71 patients undergoing surgical biopsy at the onset of lymphadenopathy. The aim of this study was to define, in multivariate analysis, the ultrasonographic parameters useful in the differential diagnosis of benign and malignant lymphadenopathy.

RESULTS

Volume, vascularization score, pulsatility index, and resistive index were significantly higher in the 53 malignant lymph nodes studied than in the 18 benign lymph nodes studied. The long-to-short axis ratio was significantly lower in neoplastic lymph nodes than in reactive lymph nodes. Stepwise logistic regression selected only the long-to-short axis ratio and the vascularization score as parameters that independently and significantly contributed to the differentiation of neoplastic from reactive lymph nodes. The diagnostic efficiency of the combined criteria evaluated by the area under the receiver operating characteristic curve was 0.8339.

CONCLUSIONS

High resolution pulsed and color Doppler ultrasound may provide information that is useful in making correct differential diagnoses of malignant or benign lymphadenopathy.

Mediastinal large B-cell lymphoma: clinical and immunohistological findings in 18 patients treated with different third-generation regimens

We report on the immunophenotype, clinical findings and response to aggressive chemotherapy of 18 patients with mediastinal large B-cell lymphoma (MLCL). Cases were collected from a series of 286 high-grade non-Hodgkin's lymphomas (HG-NHL) which, in the period September 1988 to August 1991, were enrolled in a prospective multicentre trial designed to compare the MACOP-B and F-MACHOP regimens. Immunostaining on frozen sections revealed a previously unrecognized phenotype, i.e. co-expression of B-cell (CD19, CD20, CD22, Ig-associated dimer) and activation-associated antigens (CD30 and CDw70) in about 60% of MLCL cases; in contrast, the activation-associated antigens CD25 and Ki-27 (unclustered) were consistently negative. This peculiar phenotype may reflect a derivation of the tumour from a subset of thymic activated B cells. Clinically, the patients (median age 31 years; F/M ratio 2.6) presented with bulky mediastinal mass (72%) associated with mediastinal syndrome in > 50% cases; disease was stage IIA in most cases. All 18 patients received aggressive chemotherapy (F-MACHOP 11; MACOP-B 7). Complete response (CR) was achieved in 57.1% of cases treated with MACOP-B. In contrast, the response of the 11 MLCL treated with F-MACHOP was poor (CR 18.2%) as compared to that of the 135 HG-NHL treated with the same regimen during the trial (CR 69.6%). This difference was still statistically significant after adjusting for negative prognostic factors (mediastinal mass > 10 cm plus increased LDH) and suggests that F-MACHOP might not be the most appropriate regimen for this kind of lymphoma.

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.

Cutaneous involvement in lymphoblastic lymphoma

Lymphoblastic leukemia/lymphoma (LBL) is a malignant neoplasm of precursor lymphocytes of B- or T-cell phenotype. Involvement of the skin is relatively uncommon. We examined retrospectively the clinicopathologic, immunophenotypic, and molecular genetic features of six patients with cutaneous involvement of LBL (B-LBL=5; T-LBL=1). Patients presented clinically with solitary, large tumors located on the head (3 cases) or the back (1 case), or with generalized tumors (2 cases). Ulceration was uncommon. In two patients the onset of skin lesions was concomitant to the diagnosis of lymphoblastic leukemia. Histopathologic examination showed in all cases a dense, diffuse, monomorphous infiltrate located in the entire dennis and subcutaneous fat. A typical "starry sky" pattern was observed in the majority of the lesions. In some areas neoplastic cells were aligned in a "mosaic-like" fashion. Cytomorphologically, medium sized lymphoid cells with round or convoluted nuclei, inconspicuous nucleoli and scant cytoplasm predominated. There were no significant differences in the histopathologic features of skin lesions in T- and B-LBL. In B-LBL, CD79a was more useful than CD20 in determining the phenotype of neoplastic cells (4/5 cases positive for CD79a as compared to 2/5 cases positive for CD20). TdT, CD10 and CD43 were positive in 4 cases, CD34 in 2. The case of T-LBL revealed positivity for CD1a, CD3, CD43 and TdT, and negativity for CD34 and for B-cell markers. All neoplasms were positive for CD99 and bcl-2, and showed a high proliferation rate. Molecular genetic analysis of J(H) and T-cell receptor (TCR) genes performed using a polymerase chain reaction technique revealed a monoclonal rearrangement of J(H) genes in all five B-LBLs. One of these cases showed also a concomitant TCR-gamma gene rearrangement. A monoclonal rearrangement of the TCR-gamma gene was detected in the case of T-LBL. Our study shows that skin lesions of LBL present characteristic clinicopathologic and molecular features allowing the differentiation from other cutaneous lymphomas, even in cases without clinical history of previous precursor lymphoblastic leukemia/lymphoma.

MACOP-B and involved field radiation therapy is an effective therapy for primary mediastinal large B-cell lymphoma with sclerosis

PURPOSE

To evaluate the clinical features of presentation and the response to two different third-generation regimens (F-MACHOP and MACOP-B) of primary mediastinal large B-cell lymphoma (MLBCL), a recently defined distinct clinicopathological entity of non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Thirty-seven consecutive patients with MLBCL, eight male and 29 female (F/M ratio 1:3.5) with a median age of 35 years, were enrolled in the present study. Thirty-five (94.5%) patients presented disease confined to thorax, with chest symptoms of a rapidly enlarging mass in the mediastinum in 70% and superior vena cava syndrome (SCVS) in 43% of these patients. The first 10 patients received F-MACHOP and the succeeding 27 patients MACOP-B chemotherapy, associated in 24 (88.8%) with involved field radiation therapy (IFRT). 67Gallium scan was routinely performed pre- and post-IFRT in 18 patients.

RESULTS

All 37 patients were assessable for response: 10 of 10 (100%) in the F-MACHOP and 26 of 27 (96.3%) in the MACOP-B group achieved overall responses (CR + PR). Three of 24 (12.5%) patients in PR after chemotherapy obtained CR after IFRT. Persistent Gallium avidity was observed in 16 patients after chemotherapy and in only four patients after IFRT. Thus far, four of the 10 F-MACHOP and two of the 26 MACOP-B responders have presented disease progression. The probability of progression-free survival (PFS) was 91% and 60% (P < 0.02) while overall survival (OS) was 93% and 70% (P = n.s.) at a mean follow-up of 27 and 52 months in the MACOP-B + IFRT and F-MACHOP groups, respectively.

CONCLUSION

MACOP-B + IFRT has proved to be a highly effective and less toxic therapeutic approach for primary MLBCL and appears to be superior to other third-generation chemotherapy regimens.

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.

Pathogenetic and clinical implications of Bcl-6 and Bcl-2 gene configuration in nodal diffuse large B-cell lymphomas

Bcl-6 (LAZ-3) and Bcl-2 gene rearrangements have been respectively reported in 20-35 per cent and 10-25 per cent of diffuse large B-cell lymphomas (DLBCLs). Although these genetic lesions have been associated with different clinical outcomes (i.e., more favourable in Bcl-6 rearranged cases and poorer in Bcl-2 rearranged cases), their prognostic significance is still controversial. In the present study, we have investigated by Southern blot analysis the Bcl-6 and Bcl-2 gene configuration in a series of 80 lymph nodes involved by well-characterized DLBCLs, histologically defined according to the REAL and the updated Kiel classifications. The molecular findings have been correlated with the clinical features at presentation and with response to therapy. The majority of cases (57/80 = 71.2 per cent) had a centroblastic morphology. Bcl-6 rearrangements were detected in 23/80 cases (28.8 per cent), and were similarly associated with centroblastic (18/57 = 31.6 per cent) or immunoblastic (3/11 = 27.3 per cent) histotypes. In contrast, Bcl-2 was found to be rearranged in only three cases of centroblastic lymphoma (3.8 per cent). No significant differences were found between Bcl-6 rearranged and germline cases, as far as the clinical features at presentation are concerned. Forty-one patients, in whom the lymph node biopsy was performed at diagnosis, could be evaluated for response to treatment and clinical outcome. Most of these cases (30/41 = 73.2 per cent) were nodal DLBCL, without extranodal site involvement. Analysis of the clinical outcome showed no statistically significant differences between Bcl-6 rearranged and Bcl-6 germline cases (actuarial overall survival 50 per cent vs. 48 per cent, event-free survival 45 per cent vs. 46 per cent, at 4 years). These findings confirm that Bcl-6 rearrangements are the most frequent genetic lesion in DLBCL. The incidence of Bcl-2 involvement in our series is significantly lower than the figures reported in other studies, mainly from North American countries, probably reflecting heterogeneous patient selection and/or epidemiological variability. Finally, our results suggest that no relevant clinical differences are observed between Bcl-6 rearranged and Bcl-6 germline cases, when nodal DLBCLs are considered.

Hodgkin's disease during pregnancy: diagnostic and therapeutic management

OBJECTIVES

To evaluate the possibility that women affected by Hodgkin's disease (HD) during their second or third trimester of pregnancy can safely carry their pregnancy to term.

METHODS

From 1986 to 1997, 6 women came to our Center during the second trimester of pregnancy and were diagnosed as having HD. Three of these 6 patients were treated with chemotherapy before delivery and 3 of them were kept under observation and started treatment after delivery.

RESULTS

All 6 women gave birth to a healthy female.

CONCLUSIONS

The pregnancy does not worsen the course of the illness and does not compromise long-term clinical remission and recovery.

p53 over-expression identifies a subset of nodal peripheral T-cell lymphomas with a distinctive biological profile and poor clinical outcome

Peripheral T-cell lymphomas (PTCL) are usually characterized by aggressive clinical behaviour and poor clinical outcome, but their biological background has not been extensively investigated to date, due to their low incidence, about 10% of all non-Hodgkin's lymphoma cases in Western countries, and also to the paucity of specific molecular-genetic abnormalities. Neverthless, there is increasing biological and clinical evidence that primary nodal PTCL should be considered separately from extra-nodal cases, but little is known about biological factors of possible clinical and prognostic impact. This immunohistochemical study has analysed the expression of p53, Mdm2, p21(WAF1), BCL-2 and p-glycoprotein (MDR-1 gene product) in a series of 45 cases of nodal peripheral T-cell lymphomas (PTCL) with 'high-grade' histology. The immunohistochemical findings were then correlated with proliferative activity and clinical outcome. p53 was over-expressed in 13 cases (28.9%). p53 positive cases showed significantly higher proliferative activity (p<0.01), more frequent expression of Bcl-2 (p<0.01) and less frequent expression of p21(WAF1) than p53 negative cases. Mdm2 and p-glycoprotein were expressed in 4/13 (30.8%) and 8/13 (61.5%) p53 positive cases respectively, and in none (0%) of the p53 negative cases (p<0.01). Analysis of the survival curves showed that p53 positive cases were associated with a significantly poorer clinical outcome than p53 negative cases, in terms of both overall survival (p=0.0032) and event-free survival (p=0.0004). Furthermore, multivariate analysis showed that p53 expression was the most important independent prognostic variable. These findings indicate that p53 over-expression identifies a subset of nodal PTCL cases with a distinctive biological profile (higher proliferative activity, less frequent expression of p21(WAF1) and more frequent expression of Bcl-2, Mdm2 and p-glycoprotein than p53 negative cases) and poor clinical outcome. The immunohistochemical analysis of p53 expression is a simple, rapid and low-cost method which may provide information of potential clinical and prognostic value in nodal peripheral T-cell lymphomas.

Primary effusion lymphoma in HIV-infected patients with multicentric Castleman's disease

Multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) are two B-cell lymphoproliferative diseases associated with Kaposi's sarcoma-associated herpes virus/human herpesvirus-8 (KSHV/HHV-8). Although MCD is considered a prelymphoma state, it is not known whether a pathogenetic link exists between MCD and PEL. This paper reports the clinico-pathological features of four cases of PEL (two pericardial, one pleural, and one peritoneal) developing in the context of HIV-associated MCD. Effusions, lymph nodes, spleen, and additional tissues from three autopsies were examined for morphology/immunophenotype, search for HHV-8 DNA, and assessment of immunoglobulin heavy chain gene (IgH) configuration using polymerase chain reaction (PCR)-based techniques. MCD and PEL samples contained HHV-8 DNA. Clonal IgH rearrangements were detected only in PEL, whereas MCD tissues were polyclonal. Light-chain immunostaining confirmed B-cell clonality in PEL (two lambda, one kappa, one not tested) and polyclonality in MCD. The autopsies revealed different morphological variants of visceral KS and multi-organ atypical infiltrates exhibiting immunoblastic/plasmablastic features reminiscent of PEL morphology, with a restriction of lambda-positive cells. In two cases, using microdissection and IgH PCR analysis, multiple/discrete bands were found in the infiltrates, compatible with polyclonality/oligoclonality. The case showing an oligoclonal IgH ladder contained a rearrangement of identical junctional size to the PEL clone; however, further analysis with PEL-derived clonotypic primers and sequencing of PCR products showed no amplification and nucleotide diversity, respectively, indicating that the two B-cell populations examined were clonally unrelated. These data show that MCD and PEL may co-exist in HIV-infected patients, suggesting a relevant association between these two HHV-8-related disorders. Although a definite clonal relationship between MCD and PEL was not demonstrated, it is hypothesized that in some MCD cases, within expanded polyclonal B-cell populations secondary to HHV-8 infection, clonal expansions may occur that localize into a body cavity, i.e. PEL.

Recurrent thymoma: evidence for histological progression

The clinicopathological features of nine cases of recurrent thymomas have been studied. At presentation, all cases were histologically classified as thymomas with cortical differentiation, including predominantly cortical thymoma, cortical thymoma and well-differentiated thymic carcinoma. In five cases the morphological features of the recurrence(s) were suggestive of a histological progression of the tumour from predominantly cortical thymoma to cortical thymoma and/or well-differentiated thymic carcinoma, usually associated with a more advanced clinical stage, the latter indicating a clinical progression. These findings suggest that all types of thymoma with cortical differentiation are histologically and histogenetically related neoplasms, associated with a more aggressive clinical behaviour and a significant risk of recurrence. The overall outcome of patients with recurrent thymoma in this series was poor, since six patients (66.6%) died due to the disease, 2-14 years after the first diagnosis. The clinical implication of our findings is that thymomas with cortical differentiation always need careful follow-up, even in those cases which are not obviously invasive at onset.

Expression of epidermal and nerve growth factor receptors in human thymus and thymomas

The expression of epidermal growth factor (EGF) and nerve growth factor (NGF) receptors has been investigated by immunohistochemical analysis in eight normal human thymuses and in 15 thymomas. Thymomas were classified into five different histological types--medullary, mixed, predominantly cortical, cortical thymoma and well-differentiated thymic carcinoma. In fetal and paediatric normal thymus, EGF-receptor was expressed by subcapsular, cortical and medullary epithelial cells, whereas immunoreactivity for NGF-receptor was detected on only subcapsular and medullary epithelial cells. In thymomas, independent of their histological type, EGF-receptor was expressed by a large majority of epithelial cells. In contrast, the pattern of expression of NGF-receptor in thymomas was different for the various histological types. These findings indicate that the expression of both EGF and NGF receptors in human thymomas substantially reflects their expression in normal thymus, and suggest that EGF and NGF may play a role in the ontogenesis of the human thymus as well as in the histogenesis of thymomas.

Microscopic thymoma: histological evidence of multifocal cortical and medullary origin

Twenty cases of macroscopically non-neoplastic thymuses obtained from patients with myasthenia gravis have been studied histologically. Seven cases were characterized by lymphoid follicular hyperplasia and 13 by involutional changes of variable degree. In three cases (15%), one with lymphoid follicular hyperplasia and two with involutional changes, multiple microscopic epithelial lesions, 0.2-0.4 mm in diameter and consistent with foci of microscopic thymoma, were observed. Most of them were related to the thymic cortex and one, displaying a different histological pattern, was located in a medullary area. These observations provide morphological evidence of a possible multifocal origin of thymoma from distinct epithelial clones present in the different topographic areas of the human thymus.

B- and T-cell non-Hodgkin's lymphomas with large multilobated cells: morphological, phenotypic and clinical heterogeneity

Ten cases of non-Hodgkin's lymphomas, mainly composed of large multilobated cells, have been studied. Our results are consistent with the view that they represent a somewhat heterogeneous group of lymphoid tumours displaying different morphological, clinical and immunophenotypic features. In B-cell type the large multilobated cells were histologically characterized by prominent nucleoli and distinctly basophilic cytoplasm whereas in the T-cell type they had indistinct or small nucleoli and ill-defined weakly eosinophilic cytoplasm. These differential features between B- and T-cell type were confirmed by electron microscopy. From a clinical standpoint B-cell type was characterized by a constant involvement of lymphoid tissues (lymph nodes and/or Waldeyer's ring); T-cell type showed, on the contrary, a more frequent involvement of extra-lymphoid sites (mainly bone and subcutaneous tissues). Our study provides some morphological features that may be helpful for a correct differential diagnosis in this heterogeneous group of non-Hodgkin's lymphomas.

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.