RESUMO
The microbiota, the host-associated community of microbes, play important roles in health status and whole body homeostasis of all organisms, including marine species. In bivalves, the microbiota composition has been mainly investigated in adults, whereas little information is available during development. In this work, the microbiota composition of the first larval stages of Mytilus galloprovincialis was evaluated by 16S rRNA gene-based profiling, at 24 and 48 hours post fertilization in comparison with those of eggs and sperm. The main genera detected in both larvae (Vibrio, Pseudoalteromonas, Psychrobium, Colwellia) derived from eggs. However, a clear shift in microbiota was observed in developing larvae compared to eggs, both in terms of core microbiome and relative abundance of different genera. The results provide a first insight into the composition of the microbial communities associated with gametes and early larvae of mussels. Moreover, the impact on larval microbiome of estrogenic chemicals that potentially affect Mytilus early development, 17ßestradiol-E2, Bisphenol A-BPA and Bisphenol F-BPF (10 µg/L), was investigated. Exposure to estrogenic chemicals leads to changes in abundance of different genera, with distinct and common effects depending on the compound and larval stage. Both potential pathogens (Vibrio, Arcobacter, Tenacibaculum) and genera involved in xenobiotic biotransformation (Oleispira, Shewanella) were affected. The effects of estrogenic compounds on larval microbiome were not related to their developmental effects: however, the results address the importance of evaluating the impact of emerging contaminants on the microbiota of marine invertebrates, including larval stages, that are most sensitive to environmental perturbations.
Assuntos
Bactérias/efeitos dos fármacos , Compostos Benzidrílicos/toxicidade , Estrogênios/toxicidade , Microbiota/efeitos dos fármacos , Mytilus/microbiologia , Fenóis/toxicidade , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Estrogênios não Esteroides/toxicidade , Larva , Microbiota/genética , Mytilus/efeitos dos fármacos , Mytilus/crescimento & desenvolvimento , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genética , Poluentes da Água/toxicidadeRESUMO
The potential bioactivities for alleviating Metabolic Syndrome associated risk factors were evaluated in carob (Ceratonia siliqua L.) fruit by-products, i.e. seed peel, germ and pod. Carob germ and seed peel showed higher phenolic content than pod (99.72, 80.24 and 47.06 µmol GAE g-1, respectively). Pod mostly contained gallic acid and gallotannins; seed peel and germ's showed as most abundant polyphenols quercetin and apigenin derivatives. Carob pod and seed peel revealed stronger antioxidant capacities compared to germ. The strongest antihypertensive activity was found in seed peel, followed by pod and germ. Anti-inflammatory activity showed inhibition of NO production in LPS-induced macrophages, although only pod was able of reducing pro-inflammatory mediators (TNF-α andPGD2). Finally, fat accumulation on mature adipocytes was reduced by carob seed peel and pod extracts. This work shows the potential use of pod carob by-products as food ingredients with special relevance of carob pod for attenuating metabolic syndrome.
RESUMO
Polyphenols are members of a very large family of plant-derived compounds that may have beneficial effects on human health, and thus their study has become an increasingly important area of human nutrition research. Considering that it is increasingly accepted that chronic sub-acute inflammation plays an important role in the development of insulin resistance and of diabetes in animals and in humans, the aim of the present review is to compile information concerning the anti-inflammatory effects of non-flavonoid polyphenols on diabetes prevention and/or treatment. Most of these studies have been carried out with different cultured cells and using animal models displaying different types of diabetes, such as diabetes induced by streptozotocin or streptozotocin-nicotinamide, genetic diabetes or diabetes induced by high-fat feeding. In general terms, non-flavonoid polyphenols reduce the production of inflammatory mediators, such as IL-1ß, IL-8, MCP-1, COX-2 or iNOS in these animal models of diabetes. This effect is accompanied in the vast majority of these studies by improved insulin action. In addition, some of the non-flavonoid polyphenols are also able to ameliorate or prevent several pathological alterations associated with the development of diabetes, such as nephropathy, cardiopathy or retinopathy. Very little information has been reported with regard to human studies to date. Thus, new studies are needed to confirm if the beneficial effects observed in preclinical studies can apply to human beings.
Assuntos
Anti-Inflamatórios/uso terapêutico , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Fenóis/uso terapêutico , Animais , Ensaios Clínicos como Assunto , Curcumina/uso terapêutico , Modelos Animais de Doenças , Humanos , Hidroxibenzoatos/uso terapêutico , Alcamidas Poli-Insaturadas/uso terapêutico , Estilbenos/uso terapêuticoRESUMO
In the epidermal growth factor receptor (EGFR) pathway, polymorphisms in EGFR and its ligand EGF have been studied as biomarkers for anti-EGFR treatment. However, the potential pharmacogenetic role of other EGFR ligands such as amphiregulin (AREG) and epiregulin (EREG) has not been elucidated. We studied 74 KRAS and BRAF wild-type metastatic colorectal cancer patients treated with anti-EGFR plus irinotecan. Twenty-two genetic variants in EGFR, EGF, AREG and EREG genes were selected using HapMap database and literature resources. Three tagging single-nucleotide polymorphisms in the AREG gene region (rs11942466 C>A, rs13104811 A>G, and rs9996584 C>T) predicted disease control in the multivariate analyses. AREG rs11942466 C>A and rs9996584 C>T were also associated with overall survival (OS). The functional polymorphism, EGFR rs712829 G>T, was associated with progression-free and OS. Our findings support that intergenic polymorphisms in the AREG gene region might help to identify colorectal cancer patients that will benefit from irinotecan plus anti-EGFR therapy.
Assuntos
Anfirregulina/genética , Biomarcadores/metabolismo , Camptotecina/análogos & derivados , Neoplasias Colorretais/genética , Receptores ErbB/antagonistas & inibidores , Polimorfismo Genético , Sequência de Bases , Camptotecina/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Primers do DNA , Feminino , Humanos , Irinotecano , Masculino , Metástase Neoplásica , Polimorfismo de Nucleotídeo Único , Reação em Cadeia da Polimerase em Tempo RealRESUMO
BACKGROUND AND AIMS: Epidemiological and clinical studies suggest that low-glycemic index diets could protect against weight gain. However, the relationship between these diets and adipokines or inflammatory markers is unclear. In the present study we examine how the dietary glycemic index (GI) and dietary glycemic load (GL) are associated with several adipokines and related metabolic risk markers of obesity and diabetes in a cross-sectional and longitudinal manner. METHODS AND RESULTS: 511 elderly community-dwelling men and women at high cardiovascular risk were recruited for the PREDIMED trial. Dietary data were collected at baseline and after 1 year of follow-up. The GI and GL were calculated. Plasma leptin, adiponectin and other metabolic risk markers were measured at baseline and after 1 year. At baseline, subjects in the highest quartiles of GI showed significantly higher levels of TNF and IL-6 than those in the lowest quartiles. Dietary GI index was negatively related to plasma leptin and adiponectin levels. After 1 year of follow-up, subjects with a higher increase in dietary GI or GL showed a greater reduction in leptin and adiponectin plasma levels. There was no association between GI or GL and the other metabolic markers measured. CONCLUSION: Our results suggest that the consumption of high-GI or high-GL diets may modulate plasma concentrations of leptin and adiponectin, both adipostatic molecules implicated in energy balance and cardiometabolic risk.
Assuntos
Biomarcadores/sangue , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/prevenção & controle , Carboidratos da Dieta/administração & dosagem , Índice Glicêmico , Obesidade/prevenção & controle , Adipocinas/sangue , Adiponectina/sangue , Idoso , Idoso de 80 Anos ou mais , Glicemia/análise , Doenças Cardiovasculares/sangue , Estudos Transversais , Diabetes Mellitus Tipo 2/sangue , Dieta Mediterrânea , Feminino , Seguimentos , Humanos , Interleucina-6/sangue , Leptina/sangue , Modelos Logísticos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Avaliação Nutricional , Obesidade/sangue , Resistina/sangue , Fatores de Risco , Espanha/epidemiologia , Fator de Necrose Tumoral alfa/sangueRESUMO
BACKGROUND: Single-nucleotide polymorphisms (SNPs) in genes involved in DNA repair are good candidates to be tested as phenotypic modifiers for carriers of mutations in the high-risk susceptibility genes BRCA1 and BRCA2. The base excision repair (BER) pathway could be particularly interesting given the relation of synthetic lethality that exists between one of the components of the pathway, PARP1, and both BRCA1 and BRCA2. In this study, we have evaluated the XRCC1 gene that participates in the BER pathway, as phenotypic modifier of BRCA1 and BRCA2. METHODS: Three common SNPs in the gene, c.-77C>T (rs3213245) p.Arg280His (rs25489) and p.Gln399Arg (rs25487) were analysed in a series of 701 BRCA1 and 576 BRCA2 mutation carriers. RESULTS: An association was observed between p.Arg280His-rs25489 and breast cancer risk for BRCA2 mutation carriers, with rare homozygotes at increased risk relative to common homozygotes (hazard ratio: 22.3, 95% confidence interval: 14.3-34, P<0.001). This association was further tested in a second series of 4480 BRCA1 and 3016 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2. CONCLUSIONS AND INTERPRETATION: No evidence of association was found when the larger series was analysed which lead us to conclude that none of the three SNPs are significant modifiers of breast cancer risk for mutation carriers.
Assuntos
Neoplasias da Mama/genética , Carcinoma/genética , Proteínas de Ligação a DNA/fisiologia , Epistasia Genética/fisiologia , Genes BRCA1 , Genes BRCA2 , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Carcinoma/epidemiologia , Proteínas de Ligação a DNA/genética , Feminino , Grupos Focais , Genes BRCA1/fisiologia , Genes BRCA2/fisiologia , Predisposição Genética para Doença , Heterozigoto , Humanos , Pessoa de Meia-Idade , Fenótipo , Polimorfismo de Nucleotídeo Único , Proteína 1 Complementadora Cruzada de Reparo de Raio-X , Adulto JovemRESUMO
Biallelic inactivation of ATM gene causes the rare autosomal recessive disorder Ataxia-telangiectasia (A-T). Female relatives of A-T patients have a two-fold higher risk of developing breast cancer (BC) compared with the general population. ATM mutation carrier identification is laborious and expensive, therefore, a more rapid and directed strategy for ATM mutation profiling is needed. We designed a case-control study to determine the prevalence of 32 known ATM mutations causing A-T in Spanish population in 323 BRCA1/BRCA2 negative hereditary breast cancer (HBC) cases and 625 matched Spanish controls. For the detection of the 32 ATM mutations we used the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry technique. We identified one patient carrier of the c.8264_8268delATAAG ATM mutation. This mutation was not found in the 625 controls. These results suggest a low frequency of these 32 A-T causing mutations in the HBC cases in our population. Further case-control studies analyzing the entire coding and flanking sequences of the ATM gene are warranted in Spanish BC patients to know its implication in BC predisposition.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Supressoras de Tumor/genética , Proteínas Mutadas de Ataxia Telangiectasia , Estudos de Casos e Controles , DNA/análise , DNA/genética , Análise Mutacional de DNA , Família , Feminino , Testes Genéticos , Humanos , Masculino , Prognóstico , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Mutations in BRCA1 and BRCA2 genes confer a high risk of breast and ovarian cancer but the incomplete penetrance of these mutations suggests that other genetic and/or environmental factors may modify this risk. We present a family where all affected members carried a mutation in the BRCA1 gene and the index case had suffered from cancer twice in the last 27 years, whereas her monozygotic twin sister, also a carrier of the mutation, remained healthy. As copy number variants (CNVs) contribute to phenotypic diversity, a comparative genomic hybridization array (CGH) was performed to see whether the differences in the CNV profile were a modifier factor of the phenotype in our monozygotic twins. Our results show that differences in the CNVs profile were not the cause of the extremely variable penetrance observed in our MZ twin. The search for an explanation should not therefore be limited to genetic changes at the level of the DNA sequence.
Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Dosagem de Genes , Mutação , Neoplasias Ovarianas/genética , Gêmeos Monozigóticos/genética , Adulto , Hibridização Genômica Comparativa , Análise Mutacional de DNA , Feminino , Predisposição Genética para Doença , Humanos , Pessoa de Meia-Idade , Linhagem , Fenótipo , EspanhaRESUMO
Most patients with acute myeloid leukemia (AML) and t(8;21) or inv(16) have a good prognosis with current anthracycline- and cytarabine-based protocols. Tandem analysis with flow cytometry (FC) and real-time RT-PCR (RQ-PCR) was applied to 55 patients, 28 harboring a t(8;21) and 27 an inv(16), including one case with a novel CBFbeta/MYH11 transcript. A total of 31% (n=17) of CR patients relapsed: seven with t(8;21) and 10 with inv(16). The mean amount of minimal residual disease (MRD) detected by FC in relapsed and nonrelapsed patients was markedly different: 0.3 vs 0.08% (P=0.002) at the end of treatment. The mean number of fusion transcript copies/ ABL x 10(4) also differed between relapsed and non-relapsed patients: 2385 vs 122 (P=0.001) after induction, 56 vs 7.6 after intensification (P=0.0001) and 75 vs 3.3 (P=0.0001) at the end of chemotherapy. Relapses were more common in patients with FC MRD level >0.1% at the end of treatment than in patients with < or = 0.1%: cumulative incidence of relapse (CIR) was 67 and 21% (P=0.03), respectively. Likewise, using RQ-PCR, a cutoff level of >10 copies at the end of treatment correlated with a high risk of relapse: CIR was 75% for patients with RQ-PCR >10 compared to 21% for patients with RQ-PCR levels < or = 10 (P=0.04). Combined use of FC and RQ-PCR may improve MRD detection, and provide useful clinical information on relapse kinetics in AML patients.
Assuntos
Cromossomos Humanos Par 16/genética , Cromossomos Humanos Par 21/genética , Cromossomos Humanos Par 8/genética , Leucemia Mieloide/genética , Neoplasia Residual/genética , Doença Aguda , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Inversão Cromossômica , Análise Citogenética , Feminino , Citometria de Fluxo , Seguimentos , Humanos , Cinética , Leucemia Mieloide/metabolismo , Leucemia Mieloide/terapia , Masculino , Pessoa de Meia-Idade , Neoplasia Residual/diagnóstico , Neoplasia Residual/terapia , Prognóstico , Recidiva , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Taxa de SobrevidaRESUMO
Retroviral insertional mutagenesis in BXH2 mice commonly induces myeloid leukemias. One of the most frequently involved genes in experimental studies is Meis 1. In contrast to other genes in murine models, Meis 1 has not been affected by recurrent chromosomal translocations or point mutations in human leukemias. We found a constant downregulation of the Meis 1 gene mRNA in AML1-ETO acute myeloid leukemias and in those cases harboring in frame mutations in the bZIP domain of CEBPalpha. The absence of the Meis 1 mRNA was not caused by inactivating point mutations in the coding sequence. Promoter hypermethylation was present in more than half of the cases (9/14), including samples obtained from the widely employed Kasumi-1 cell line. Double treatment with 5-Aza-2'-deoxycytidine and trichostatin A of the Kasumi-1 cell line partially reverses Meis 1 inhibition. HoxA9 levels were also low. In a cell line model (U937 Tet AML1-ETO), AML1-ETO expression was not associated with Meis 1 suppression at 72 h. Nevertheless, Meis 1 repression is dependent on the AML1-ETO transcript levels in treated leukemic patients. Chimeric products that arise from chromosomal translocations may be associated with locus-specific epigenetic inactivation. It remains to be investigated when this methylation process is acquired and which are the basic mechanisms underlying these molecular events in AML1-ETO and CEBPalpha-mutated AML.
Assuntos
Azacitidina/análogos & derivados , Metilação de DNA , Proteínas de Homeodomínio/genética , Leucemia Mieloide/genética , Proteínas de Neoplasias/genética , Proteínas de Fusão Oncogênica , Regiões Promotoras Genéticas/genética , Fatores de Transcrição , Doença Aguda , Adulto , Azacitidina/farmacologia , Medula Óssea , Estudos de Casos e Controles , Linhagem Celular Tumoral , Subunidade alfa 2 de Fator de Ligação ao Core , Metilação de DNA/efeitos dos fármacos , Decitabina , Regulação para Baixo/efeitos dos fármacos , Proteínas de Homeodomínio/fisiologia , Humanos , Ácidos Hidroxâmicos/farmacologia , Leucemia Mieloide/tratamento farmacológico , Proteína Meis1 , Proteínas de Neoplasias/fisiologia , RNA Mensageiro/análise , Proteína 1 Parceira de Translocação de RUNX1Assuntos
Proteínas de Ligação a DNA/genética , Leucemia Mieloide/genética , Mutação/genética , Síndromes Mielodisplásicas/genética , Proteínas de Neoplasias/genética , Proteínas Proto-Oncogênicas , Fatores de Transcrição/genética , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Subunidade alfa 2 de Fator de Ligação ao Core , Análise Mutacional de DNA , Feminino , Humanos , Leucemia Mieloide/diagnóstico , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/diagnóstico , Polimorfismo Conformacional de Fita SimplesRESUMO
We report a family with a new phenotype of autosomal recessive muscle dystrophy caused by a dysferlin mutation. The onset of the illness is distal, in the muscles of the anterior compartment group. The disease is rapidly progressive, leading to severe proximal weakness. Muscle biopsy showed moderate dystrophic changes with no vacuoles. Dysferlin immunostaining was negative. Gene analysis revealed a frameshift mutation in the exon 50 (delG5966) of the DYSF gene. This phenotype further demonstrates the clinical heterogeneity of the dysferlinopathies.
Assuntos
Síndrome do Compartimento Anterior/genética , Proteínas de Membrana , Proteínas Musculares/genética , Distrofias Musculares/genética , Adulto , Síndrome do Compartimento Anterior/patologia , Disferlina , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Músculos/patologia , Distrofias Musculares/patologia , Mutação/genética , Linhagem , FenótipoRESUMO
INTRODUCTION: Muscular dystrophies due to calpain deficiency are the first example of a muscular dystrophy due to the mutation of a gene codifying for a non-structural enzymatic protein of unknown function and substrate. DEVELOPMENT: More than 70 mutations have been described in the gene structure, localized to chromosome 15. Although the time course and topography is fairly homogeneous, correlation between the different mutations and the phenotype has still to be analyzed. The age of onset of symptoms is usually between 8 and 14, with no difference between the sexes. There is a slow but uniformly progressive course starting in the pelvis and extending to the shoulder and the distal musculature. Almost all patients are confined to a wheelchair twenty years after onset of the disease. There is no facial, oculomotor or bulbar involvement and gemellar pseudohypertrophy is rare. However, a winged scapula and marked lumbar hyperlordosis is universal. No cardiac or cognitive changes have been observed. Muscle CT shows a pattern of atrophy, mainly of the posterior and medial muscle compartments and of the posterosuperficial group of the legs, which varies depending on the time the disorder has been present. This condition is the commonest etiological group of the dystrophy syndromes, especially of those of late infancy or juvenile onset, in the open populations studied to date. Muscle biopsy, stained by all methods available, is essential to rule out other types of progressive dystrophies secondary to deficiencies of structural proteins.
Assuntos
Calpaína/deficiência , Calpaína/genética , Distrofias Musculares/genética , Adulto , Biópsia , Criança , Pré-Escolar , Diagnóstico Diferencial , Glicoproteínas/genética , Humanos , Músculo Esquelético/patologia , Distrofias Musculares/diagnóstico , Mutação Puntual/genéticaRESUMO
The bcl-2 gene is rearranged in most cases of follicular lymphoma and the breakpoint clusters are found in two specific regions: mbr and mcr. Rearrangements of the immunoglobulin heavy chain genes (IgH) result in a deregulation of the gene and increased transcription of mRNA for the bcl-2 protein. In cases of rearrangement of the light chains (variant translocations), a third breakpoint has been described at the 5' part of the bcl-2 locus (vcr). In the present case, we report the molecular analysis of an FL transformed into a blastic phase unresponsive to chemotherapy. Molecular studies revealed a typical bcl-2 rearrangement at the major locus (mbr). Vcr rearrangements was also observed with only a single restriction enzyme. At the same time, SSCP analysis of exon 5 of the p53 locus disclosed an abnormal conformer. Direct sequencing revealed a point mutation at codon 163 (A --> G). Immunohistochemical analysis of the affected sites disclosed overexpression of p53 and bcl-2. It is concluded that p53 mutation can contribute to blastic transformation in cases of follicular lymphomas with double rearrangement at the bcl-2 locus (mbr/vcr).
Assuntos
Crise Blástica/genética , Genes bcl-2 , Genes p53 , Linfoma Folicular/genética , Mutação Puntual , Translocação Genética/genética , Crise Blástica/patologia , Códon/genética , Análise Mutacional de DNA , DNA de Neoplasias/genética , Éxons/genética , Evolução Fatal , Feminino , Genes de Imunoglobulinas , Humanos , Linfoma Folicular/patologia , Pessoa de Meia-Idade , Polimorfismo Conformacional de Fita SimplesRESUMO
BACKGROUND AND OBJECTIVE: Improvements in therapy for patients with B-cell acute lymphoblastic leukemia (ALL) and Burkitt's lymphoma (BL) depend on the identification of subsets of patients who require more intensive therapy. Abnormalities of the p53 gene are the most common molecular lesions in human cancer, and may be of prognostic significance in hematologic malignancies. In this study, we examined the p53 gene status in a group of patients with ALL/BL to determine whether some types of mutants were more frequent in this selected group of patients. METHODS: We selected a group of 16 patients with acute lymphoblastic leukemia (ALL) and Burkitt's lymphoma (BL) in order to investigate the presence of p53 mutations. DNA obtained from affected organs (bone marrow, lymph node and a renal mass) was used for the molecular studies. Single-strand conformation polymorphism (SSCP) analysis of exons 5 to 9 of the gene was used to detect p53 mutants. After detecting an abnormal migration pattern on the SSCP, mutations were determined by direct sequencing. RESULTS: Point mutations were found in eight patients; a misense mutation in seven cases and a non-sense mutation in one case. The normal allele was also identified in 7 mutated samples. The same mutation at codon 282 was identified in three different patients, in whom an identical conformer was detected after SSCP analysis. Mutation at codon 282 was present in an extramedular relapse (renal) appearing after a BMT. No such alteration was present in the bone marrow analyzed at the same time. INTERPRETATION AND CONCLUSIONS: Our findings suggest that p53 mutations are quite frequent in recognized clinical groups. The criteria chosen in this study allowed us to identify a high percentage of the samples with mutation. Different malignant phenotypes could be determined by functional heterogeneity of p53 mutants.
Assuntos
Linfoma de Burkitt/genética , Proteína Supressora de Tumor p53/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Illegitimate recombinase activity promoted by the recombination activating RAG-1 and RAG-2 is assumed to be involved in the pathogenesis of the chromosomal translocations observed in lymphoid neoplasias. We analyzed the complete coding region of the RAG-1 gene in patients with lymphoid neoplasis using a multiple PCR-SSCP (single strand conformation polymorphism) strategy. Nine multiple myelomas, 17 non-Hodgkin's lymphomas, 18 acute lymphocytic leukemias, 37 chronic lymphocytic leukemias and 33 non-neoplastic controls were studied. To screen the entire RAG-1 gene we used primers overlapping genomic segments of the RAG-1 coding sequence (nucleotides 87 to 3311). Samples with an abnormal band pattern in the SSCP were cloned and sequenced. Successful amplification was achieved with our protocol. The multiple PCR-SSCP analysis proved to be a feasible and sensitive strategy for studying variations in the sequence of the RAG-1 gene. No mutations other than the three previously reported sequence variations were detected. Although mutations in this gene do not appear to be common in lymphoid neoplasias, it would be interesting to ascertain whether the different variant forms of RAG-1 protein have an abnormal recombinase activity.