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Biomedical subjects

M Colombi

Publications and source records attributed to M Colombi.

At least 19 recordsLinked to original sources

Consequence analysis in LPG installation using an integrated computer package.

This paper presents the prototype of the computer code, Atlantide, developed to assess the consequences associated with accidental events that can occur in a LPG storage plant. The characteristic of Atlantide is to be simple enough but at the same time adequate to cope with consequence analysis as required by Italian legislation in fulfilling the Seveso Directive. The application of Atlantide is appropriate for LPG storage/transferring installations. The models and correlations implemented in the code are relevant to flashing liquid releases, heavy gas dispersion and other typical phenomena such as BLEVE/Fireball. The computer code allows, on the basis of the operating/design characteristics, the study of the relevant accidental events from the evaluation of the release rate (liquid, gaseous and two-phase) in the unit involved, to the analysis of the subsequent evaporation and dispersion, up to the assessment of the final phenomena of fire and explosion. This is done taking as reference simplified Event Trees which describe the evolution of accidental scenarios, taking into account the most likely meteorological conditions, the different release situations and other features typical of a LPG installation. The limited input data required and the automatic linking between the single models, that are activated in a defined sequence, depending on the accidental event selected, minimize both the time required for the risk analysis and the possibility of errors. Models and equations implemented in Atlantide have been selected from public literature or in-house developed software and tailored with the aim to be easy to use and fast to run but, nevertheless, able to provide realistic simulation of the accidental event as well as reliable results, in terms of physical effects and hazardous areas. The results have been compared with those of other internationally recognized codes and with the criteria adopted by Italian authorities to verify the Safety Reports for LPG installations. A brief of the theoretical basis of each model implemented in Atlantide and an example of application are included in the paper.

Accidents, Occupational↗

A -96C-->T mutation in the promoter of the collagen type VII gene (COL7A1) abolishing transcription in a patient affected by recessive dystrophic epidermolysis bullosa.

Hereditary dystrophic epidermolysis bullosa (DEB) refers to a group of clinically heterogeneous skin blistering diseases due to mutations in the collagen type VII gene (COL7A1). We report two novel mutations found in a patient affected by the most severe form of DEB, the recessive Hallopeau-Siemens variant (HS-RDEB): the R1978X nonsense mutation, in exon 72, and the -96C-->T transition, in the promoter region. The allele specific analysis of the transcripts from skin fibroblasts of the patient showed that the -96C-->T mutation is associated to the absence of collagen type VII (COLVII) mRNA. This mutation, the first one ever identified in the promoter of COL7A1, falls in an Sp1 motif, localized between nucleotides -96 and -91. Gel shift analysis indicated that the -96/-91 sequence is a functional Sp1 site and that the -96C-->T transition inhibits the binding of the trascription factor. These data indicate that the -96/-91 sequence is a crucial Sp1 site whose integrity is necessary for COL7A1 expression. The compound heterozygosity for the -96C-->T null mutation and for the R1978X mutation leads to the absence of COLVII at skin level and to the severe phenotype of the HS-RDEB patient. Hum Mutat 16:275, 2000.

Cells, Cultured↗

Dexamethasone-induced healing of chronic leg ulcers in a patient with defective organization of the extracellular matrix of fibronectin.

Previous investigations have shown that skin fibroblasts derived from patients affected by Ehlers-Danlos syndrome (EDS) lack an organized extracellular matrix (ECM) of fibronectin (FN). As retarded wound healing is a sign of EDS, we hypothesized that a young healthy man suffering from chronic recalcitrant leg ulcers might be affected by a defect of FN-ECM organization similar to that observed in EDS. Immunofluorescence of cultured skin fibroblasts obtained from skin biopsies from the patient and a control demonstrated that the patient's fibroblasts lacked FN-ECM organization, in contrast with those of the control; this was restored by 10-7 mol/L dexamethasone (DEX) in vitro. DEX treatment of the patient was associated with healing of his leg ulcers. In conclusion, DEX may be effective in reversing impaired wound healing associated with a lack of FN-ECM organization

Adult↗

OPP-EBV-CAD regimen as salvage treatment in advanced refractory or resistant multiple myeloma.

With the aim of developing an effective therapy for heavily pretreated refractory MM outpatients, we evaluated the OPPEBVCAD regimen, a Hodgkin's disease-derived protocol that includes many drugs effective in MM administered in a sequential schedule. Twenty-two pts aged 42-72 years, with symptomatic highly-pretreated refractory (18 cases), or primary resistant MM (four cases. including two pts with plasma cell leukemia-PCL) received this therapy every 28 days (2-4 cycles, followed by a maintenance program). Therapeutic response (Chronic Leukemia-Myeloma Task Force criteria) and performance status (PS) and pain (W.H.O.) were evaluated. All of the pts were evaluable for response. There were 9 (40%) objective responses (OR: stabilization of blood counts and bone lesions, serum calcium normalization, 50% or more reduction in the concentration of serum monoclonal component (MC), 90% reduction in Bence-Jones proteinuria), 8 (36%) partial responses (PR: 25-50% reduction in serum MC), 1 no response or stable disease (NR), and 4 (18%) cases of progressive disease (PD). OR plus PR were 77%. Of the 4 primary resistant tumors (2 PCL and 2 MM), 2 achieved PR, 1 OR (a PCL case) and 1 progressed. Median survival was 15 months for responding pts (OR plus PR) and 4.5 months for non-responders (NR plus PD). PS and pain improved in 15 pts and did not change in 9. The most frequent side effects were cytopenias, with one drug related infective death. The OPPEBVCAD regimen proved to be an effective therapy for refractory relapsing or primary resistant MM: in responders (two-thirds of the pts), survival was prolonged by about 10 months. Its efficacy in anthracycline-treated pts, as well as the feasibility of using it on an outpatient basis without any continuous drug infusions, make this regimen a promising third line salvage therapy.

Adult↗

Soluble cytokine levels correlate with the activity and clinical stage of Hodgkin's disease at diagnosis.

The serum levels of some cytokines seem to correlate with outcome in Hodgkin's disease (HD) and may be helpful in formulating new and better prognostic systems. The aim of this study was to analyse the correlations between the serum levels of different cytokines and the clinico-hematological features suggestive of a worse prognosis. The study involved 31 pts with a "de novo" diagnosis of HD (median age: 30 yrs; M/F: 13/18; stage I/II vs III/IV: 19/12; B symptoms: 12; bulky disease and extranodal disease: 9). The serum levels of sCD30, TNFalpha, TNF receptor I and II, IL6, IL6 receptor, IL10, sICAM-1 were evaluated at diagnosis, and correlated with gender, age (< or =/> 30), stage (I-II vs III-IV), systemic symptoms, bulky disease, ESR (</> or = 40), serum copper (< or =/> 170 microg/dL), WBC counts (< or =/> 15x10(9)/L), prognostic scores (PS) according to Hasenclever (</> or = 2), and the presence of extranodal disease. Stages III/IV were associated with significantly higher levels of sCD30 and TNF-RI (p=0.03), systemic symptoms with significantly higher levels of sCD30, TNFalpha, IL6, TNF-RI (p=0.027, 0.03, 0.0005, 0.002), bulky disease with TNF-RI (p=0.03), high ESR with IL6 and TNF-RI (p=0.0011, 0.0001), high WBC counts with sCD30, IL6, TNF-RI (p=0.03, 0.002, 0.01), high serum copper with sCD30 and IL6 (p=0.05, 0.0004), higher PS with sCD30, IL6, TNF-RI (p=0.002, 0.0003, 0.005), extranodal disease with TNFalpha and IL6 (p=0.05, 0.01). It was possible to define cut-off levels for some cytokines (sCD30 > 33.15 U/mL, TNFalpha > 29.71 pg/mL, IL6 > 12.43 pg/mL, TNF-RI > 3.23 ng/mL, IL6-R > 57 ng/mL) that significantly correlate with systemic symptoms, higher disease stages, ESR, serum copper, WBC counts and PS. Our study shows that high sCD30, TNFalpha, IL6 and TNF-RI levels are associated with advanced disease or a worse prognostic score. In the context of multiparametric HD staging, cytokine evaluation may be useful for identifying candidates for more intensive therapies.

Adolescent↗

Three homozygous PTC mutations in the collagen type VII gene of patients affected by recessive dystrophic epidermolysis bullosa: analysis of transcript levels in dermal fibroblasts.

The Hallopeau-Siemens variant of recessive dystrophic epidermolysis bullosa (HS-RDEB) is a severe inherited skin disease characterized by the absence of collagen type VII (COLVII) and anchoring fibrils (AF), caused by mutations in collagen type VII gene (COL7A1). Mutations leading to the formation of premature termination codons (PTCs) of translation are the characteristic genetic lesions in HS-RDEB patients; many PTC mutations have been found to be associated with a marked reduction or complete absence of COLVII mRNA. In this article, we report homozygosity for three different mutations in the COL7A1 of HS-RDEB patients. One mutation, the R2685X, falling in exon 109, is a novel mutation, whereas the other two, the 425A-->G falling in exon 3 and the 497insA in exon 4, have been previously identified in compound heterozygosity with different mutations in other unrelated RDEB patients. Haplotype analysis in three Italian families carrying the 497insA mutation suggested a common origin of this mutation and indicated that this is an ancestral Italian mutation. All these mutations generate PTCs and are associated with the absence of COLVII expression, as detected by immunofluorescence analysis of the patient's skin. Evaluation of the levels of the mutated COLVII mRNAs in cultured skin fibroblasts of the patients and of their parents showed that all the mutated transcripts were expressed at consistent levels. Therefore, our results indicate that a marked mRNA reduction is not a constant feature associated with PTC mutations in COL7A1.

Adolescent↗

Cyclosporin A promotes translational silencing of autocrine interleukin-3 via ribosome-associated deadenylation.

Translation is regulated predominantly by an interplay between cis elements at the 3' and 5' ends of mRNAs and trans-acting proteins. Cyclosporin A (CsA), a calcineurin antagonist and blocker of interleukin-2 (IL-2) transcription in T cells, was found to inhibit translation of IL-3 mRNA in autocrine mast cell tumor lines. The mechanism involved ribosome-associated poly(A) shortening and required an intact AU-rich element in the 3' untranslated region. FK506, another calcineurin inhibitor, shared the effect. The translational inhibition by CsA was specific to oncogenically induced lymphokines IL-3 and IL-4 but not to IL-6, c-jun, and c-myc, which are expressed in the nonmalignant precursor cells. Furthermore, no translational down-regulation of the mRNA was observed in IL-3-transfected precursor cells. These data suggest that translational silencing is associated with the tumor phenotype.

Animals↗

Quantitative in situ hybridization for the evaluation of gene expression in asynchronous and synchronized cell cultures and in tissue sections.

We describe an image analysis (IA) system that has been applied for the quantitative evaluation of mRNAs evidenced by in situ hybridization (ISH) with radiolabelled probes in cultured cells and in tissue sections. The ISH-IA method was used for the evaluation of cultured cell morphological parameters such as cell and nucleous area (CA and NA, respectively) in parallel with the levels of mRNAs detected as hybridization grains areas (GA). The evaluation of these parameters, together with the analysis of the levels of mRNAs (c-jun, cyclin A) specific for given cell cycle phases (i.e. G1 and S/G2), allowed the identification, in asynchronous cultures of human skin fibroblasts, of cells in G1 and S/G2 phases. The mRNA levels measured by ISH-AI were comparable with those detected by RT-PCR. This method was also applied for the analysis of fibronectin (FN) gene expression in control skin fibroblasts in relationship with the different phases of the cell cycle and in comparison with a tumor cell line (Sk-Hep1), heterogeneous either for morphometric parameters or for the levels of this transcript. Finally, the ISH-AI was applied for the semiquantitative evaluation of the expression, localization and alternative splicing pattern of FN mRNA in normal liver and in hepatocellular carcinoma (HCC) tissue sections.

Animals↗

Effect of dexamethasone on the assembly of the matrix of fibronectin and on its receptors organization in Ehlers-Danlos syndrome skin fibroblasts.

The effect of dexamethasone (DEX) on the expression of fibronectin (FN), proalpha(1)(I) collagen (Col1), integrin alpha(2), alpha(5)and beta(1)subunits mRNAs, were studied by quantitative in situ hybridization (ISH) with radiolabelled probes in relationship with the organization of the extracellular matrix (ECM) of FN in human skin fibroblasts. In particular, two fibroblast strains were analysed, one derived from a control donor, typically organizing a rich ECM of FN, and the other from a patient affected by Ehlers-Danlos syndrome (EDS), which did not assemble the FN-ECM. Treatment of both fibroblast strains with 10(-7) m DEX slightly enhanced the level of FN mRNA (by about 1.5-fold), did not influence the level of alpha(5)subunit mRNA and reduced Col1, alpha(2)and beta(1)integrin subunits mRNAs by 2-3-fold. These results show that, in these cells, DEX coordinately downregulates the expression of Col1 and its specific integrin alpha(2)beta(1). Moreover, DEX regulates in a different manner the alpha(5)and beta(1)subunits forming the main FN receptor (FNR) in skin fibroblasts. Immunofluorescence microscopy evidencing the FN-ECM and integrins containing alpha(5)and beta(1)subunits showed that in control cells DEX induced a slight enhancement of the FN-ECM and of the alpha(5)beta(1)receptors patches. Therefore, in these cells the decrease of beta(1)FN receptor subunit mRNA, as well as the decrease of Col1 and its receptor mRNAs, did not influence the FN-ECM assembly. In EDS fibroblasts, DEX decreased the cytoplasmic accumulation of FN and induced the assembly of a rich FN-ECM through the formation of large FNR integrin patches, codistributing with the FN-ECM. We suggest that in EDS skin fibroblasts DEX corrects the defective FN-ECM favouring the sorting and the organization of FN and its alpha(5)beta(1)integrin receptor.

Cells, Cultured↗

Low-grade MALT lymphoma involving multiple mucosal sites and bone marrow.

Mucosa-associated lymphoid tissue (MALT) lymphomas are indolent neoplasms which tend to remain localized for a long time before spreading. We describe here the case of a 36-year-old woman with a low-grade MALT lymphoma involving the lung, stomach, lingual tonsil, and bone marrow at the time of diagnosis. The clonal origin of the pulmonary and bone marrow neoplastic infiltrates was assessed by means of gene rearrangement analysis. All of the involved sites were infiltrated by centrocyte- and monocytoid-like cells expressing the B-cell-associated antigens CD19 and CD20 and showed IgM lambda chain restriction; no CD5, CD10, or CD43 expression was detectable. As the patient had a history of recurrent bronchitis, and computed tomography performed 3 years before the lymphoma diagnosis had already revealed a lesion of the left lung, we conclude that the present case probably represents a pulmonary low-grade MALT lymphoma characterized by an early and unusual involvement of different mucosal sites and bone marrow.

Adult↗

Treatment and prognosis in a series of primary extranodal lymphomas of the ocular adnexa.

BACKGROUND: The aim of this study was to assess clinicopathological characteristics and outcome in a series of primary ocular adnexal lymphomas (POALs). PATIENTS AND METHODS: Nineteen patients with localised (stage IE) POAL were followed for a median of 96 months (24-156). The diagnosis was based on surgical biopsies followed by immunohistochemistry in 16 cases or fine-needle aspiration followed by immunocytophenotypic analysis in three cases. Twelve patients were treated with local radiotherapy (RT), five with chemotherapy (CT), and two refused further therapy after apparently radical tumour removal achieved by the diagnostic excisional biopsy. RESULTS: The histological and immunological pattern was consistent with a diagnosis of MALT-type lymphoma (11 cases), follicular center non-Hodgkin's lymphoma (three cases). a large-cell variant of Burkitt's lymphoma (one case), and large-cell transformed MALT lymphoma (one case). Low-grade lymphoma was diagnosed in the three cases which underwent fine-needle aspiration biopsy. All of the patients achieved and maintained complete remission except for those treated with surgical excision alone (two MALT conjunctival lymphoma cases): one of these relapsed locally, the other experienced the systemic spread of a transformed diffuse large-cell lymphoma and died 72 months after diagnosis. The side effects consisted of two cases of RT-related cataract after 52 and 72 months. CONCLUSIONS: Regardless of histology, prognosis was excellent when surgery plus RT was adopted, and CT seems to be a valid alternative to RT. Surgery alone may be sub-optimal.

Adult↗

Allelic deletion at chromosome 11p13 defines a tumour suppressor region between the catalase gene and D11S935 in human non-small cell lung carcinoma.

A previous study of 48 primary non-small cell lung carcinomas (NSCLC) for allelic loss at five polymorphic chromosome 11p loci indicated regions of allelic deletion for both 11p13 and 11p15. To further delineate the extent of this deletion 28 NSCLCs were examined by high resolution deletion mapping for allelic loss at 11p13.95% (18/28) of the informative cases displayed allelic loss at the catalase gene locus (CAT), 64% (18/28) at D11S935 and D11S941E, respectively, and 23% (6/26) at D11S907. The minimal region of deletion is bordered by CAT and D11S935 and spans about 3 cM. The relationship between allelic loss within this chromosomal region, the presence of a putative predisposition locus and the pathogenetics of NSCLC are discussed.

Adult↗

Weekly administration of vincristine, cyclophosphamide, mitoxantrone and bleomycin (VEMB) in the treatment of elderly aggressive non Hodgkin's lymphoma. Gruppo Italiano per lo Studio dei Linfomi.

BACKGROUND AND OBJECTIVE: Aim of the study was to assess the efficacy of VEMB, a short-lasting therapeutic regimen (50 days) which alternates two myelotoxic drugs (cyclophosphamide and mitoxantrone) every week with two less hematologically toxic drugs (vincristine and bleomycin) in the treatment of aggressive NHL in the elderly (over 70). DESIGN AND METHODS: Between November 1994 and March 1996, 37 patients aged more than 70 years, with highly or moderately malignant NHL (according to the Working Formulation) have been enrolled into the study. The stage of the disease ranged between II and IV according to Ann Arbor. Mean age was 77 years; 14 patients (38%) had stage IV; 19 patients (51%) had LDH higher than normal; 26 patients (70%) had extranodal and 9 patients (24%) had bulky disease at time of diagnosis. RESULTS: Sixty-two percent of patients achieved a complete and 22% a partial remission. Non-responders amounted to 5%. Four patients (11%) died during the therapy. Nine patients (24%) experienced grade III-IV neutropenia. The most frequently observed event was mild neurotoxicity (43% of cases). The overall survival rate at 30 months was 55%. DFS at 24 months was 66%. INTERPRETATION AND CONCLUSIONS: VEMB is a therapeutic regimen whose efficacy is comparable to that of the other derived MACOP-B therapeutic regimens used in the elderly NHL. It has proved to have a good feasibility, though the number of toxic deaths should not be neglected.

Aged↗

A pilot study on the use of the ProMACE-CytaBOM regimen as a first-line treatment of advanced follicular non-Hodgkin's lymphoma. Gruppo Italiano per lo Studio dei Linfomi.

BACKGROUND: The role of intensive conventional dose chemotherapy in advanced low grade non-Hodgkin's lymphomas is a matter of debate. The Gruppo Italiano per lo Studio dei Linfomi conducted a study to evaluate the efficacy and toxicity of a third-generation polychemotherapeutic regimen, ProMACE-CytaBOM, as a first-line therapy in a selected group of patients with advanced follicular non-Hodgkin's lymphoma (Fo-NHL) who were younger than 60 years. METHODS: Thirty-nine patients were included in the study (14 males, 25 females; median age, 44 years; age range, 22-60 years). Their WF histotypes were B (9 patients), C (23 patients), and D (7 patients). All of the patients had disease in an advanced clinical stage (Stage III, 15 patients; Stage IV, 24 patients), and 9 patients had B symptoms. According to the age-adjusted International Prognostic Index (IPI), 20 patients exhibited low-intermediate risk, 14 high-intermediate risk, and 5 high risk. Three of the patients were not considered evaluable because they withdrew their consent after three (one patient) and four (two patients) cycles of therapy (one of these patients was in complete remission [CR], and two were in partial remission [PR]). Of the 36 evaluable patients, 4 received IF-RT after the 6 planned cycles of therapy. RESULTS: CR was achieved in 20 patients (55.5%) and PR in 14 (38.8%). One patient (2.7%) experienced disease progression during the treatment program. Eight of the 20 patients with CR (40%) relapsed. Eight patients (22.2%) died: 6 died of disease progression, 1 died of therapy consequences, and 1 died of an unrelated cause. With a median follow-up of 49 months (range, 28-79 months), the disease free survival rate was 60%. The overall survival rate was 80% after a median follow-up of 44 months (range, 3-79 months). The IPI stratification of patients showed a borderline statistical difference in terms of time to treatment failure and overall survival. The main hematologic toxicity was neutropenia (Grade 3 in approximately 10% of patients). One patient died of sepsis. Cotrimoxazole prophylaxis was always given. Cardiac toxicity (Grade 3) was observed in 1 patient at the end of the planned therapy. The average relative dose intensity of the drugs was 89% of the projected dose, without the regular use of growth factors. CONCLUSIONS: This study indicates that ProMACE-CytaBOM could be a suitable regimen for adult patients with advanced Fo-NHL, allowing a good CR rate and very good disease free survival rate. However, the occurrence of severe, albeit limited, adverse effects suggests that this regimen should first be used in controlled therapeutic protocols to verify its efficacy with respect to less intensive approaches.

Adult↗

Poor prognosis in non-villous splenic marginal zone cell lymphoma is associated with p53 mutations.

We have recently reported a series of 15 non-villous splenic marginal zone lymphoma patients, six of whom showed p53 mutations (40%). This molecular alteration did not correlate with any particular clinico-pathologic feature at diagnosis. After a median follow-up of 56 months, four cases evolved into aggressive fatal non-Hodgkin's lymphoma (NHL) and two had refractory progressive disease; interestingly, p53 mutations were demonstrated in five of these patients at diagnosis. As the patients with wild-type p53 presented responsive or indolent disease, this genetic alteration may be an early marker of aggressive transformation or refractoriness. p53 evaluation at diagnosis could be advisable in this particular subset of NHL.

Adolescent↗

Role of different hematologic variables in defining the risk of malignant transformation in monoclonal gammopathy.

The presenting clinico-hematologic features of 386 patients with nonmyelomatous monoclonal gammopathy (MG) were correlated with the frequency of malignant transformation to evaluate the most important variables conditioning its evolution into multiple myeloma (MM) or Waldenström macroglobulinemia (WM). Most of the patients (335) had monoclonal gammopathy of undetermined significance (MGUS: 39 IgA, 242 IgG, 54 IgM): the remaining 51 patients (12 IgA, 39 IgG) fulfilled all of the MGUS diagnostic criteria (according to Durie) except that bone marrow plasma cell (BMPC) content was 10% to 30%, and so they were defined as having monoclonal gammopathy of borderline significance (MGBS). There were no significant differences between the MGUS and MGBS groups in terms of age, sex, or median follow-up. After a median follow-up of 70 and 53 months, respectively, 23 of 335 MGUS and 19 of 51 MGBS patients had undergone a malignant evolution. Univariate analysis of the IgA and IgG patients showed that the cumulative probability of the disease evolving into MM correlated with diagnostic definition (MGBS v MGUS), BMPC content (> or = 10% v < 5% and < or = 5% v > 5%) and reduced serum polyclonal Ig. In the IgG cases, there was also a significant correlation with detectable Bence Jones proteinuria, serum monoclonal component (MC) levels and age at diagnosis (> 70 v < = or 55 years). In the IgG cases as a whole, the same variables remained in the Cox model where the BMPC percentage was considered after natural logarithmic transformation and the monoclonal component as g/dL value. The relative risks of developing MM are the following: 2.4 for each 1 g/dL increase of IgG, serum MC, 3.5 for detectable light chain proteinuria, 4.4 for the increase of 1 unit in log. BMPC percentage, 6.1 for age > 70, 3.6 and 13.1 for a reduction in one or two polyclonal Ig. In conclusion, our study allows the identification of a particular subset of MGUS patients (MC < = or 1.5 g/dL, BMPC < 5%, no reduction in polyclonal Ig and no detectable light chain proteinuria) at very low-risk of evolution, who can be considered as having benign monoclonal gammopathies. We also describe a previously undefined group of MG patients (with monoclonal gammopathy of borderline significance) who are at high-risk of malignant evolution. These findings could have a considerable impact on the cost/benefit ratio of monitoring programs in these patients.

Aged↗

Multilobated B cell lymphoma (Pinkus variant) with isolated muscular localization in a patient with systemic sclerosis: a case report.

The association of systemic sclerosis (SSc) and non-Hodgkin's lymphoma (NHL) is a rare event whose pathogenesis remains to be clarified. We describe a case of NHL in a patient with SSc, in whom the NHL was particular in terms of clinical presentation (primitive muscle and bone involvement) and histologic type (large multilobated B-cell variant). The lymphoma was clinically aggressive but responded well to therapy. Surveillance for the development of "atypical" NHL is suggested in SSc cases.

Aged↗

Frequent TP53 gene alterations (mutation, allelic loss, nuclear accumulation) in primary non-small cell lung cancer.

Mutations of the TP53 tumour suppressor gene have been reported for many human cancers. A variety of TP53 mutations have also been reported for both primary non-small cell lung cancer (NSCLC) and associated metastases. To assess the pathogenetic significance of TP53 gene alterations in NSCLC, 24 paired samples of primary NSCLC and the corresponding normal lung tissue were analysed for mutations of the TP53 gene (exons 5-8) using exon-specific PCR, single-strand conformation polymorphism PCR (SSCP-PCR) and direct DNA sequencing; for p53 protein accumulation by immunohistochemistry and for 17p allelic loss using restriction fragment length polymorphism (RFLP) probes on Southern blots and amplified fragment length polymorphism-PCR. TP53 point mutations were observed in 9/24 (38%) tumours encompassing a total of 14 mutations. Two tumours displayed the same double mutation while a third harboured four different mutations. Seventeen of 24 NSCLCs (71%) overexpressed p53 protein and all 17 immunopositive tumours (100%) showed a mutation and/or allelic loss at the D17S30 locus. Of the 17 NSCLCs informative at the DS17S30 locus, 10 (59%) showed allelic loss, of which five (50%) were also mutated on the remaining TP53 allele. These results suggest that TP53 gene alterations are involved in the pathogenesis of primary NSCLC and that such alterations may serve a selective role in the development of NSCLC by diminishing the apoptotic potential of bronchial epithelial cells heterozygous for a TP53 point mutation. This may also explain the accumulation of multiple TP53 point mutations in 3/24 of our NSCLC samples.

Alleles↗