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M A Pierotti

Publications and source records attributed to M A Pierotti.

At least 73 records · Page 4Linked to original sources
PubMed1998

Prognostic value of loss of heterozygosity and KRAS2 mutations in lung adenocarcinoma.

The prognostic values of loss of heterozygosity (LOH) at loci frequently involved in non-small cell lung cancer and of KRAS2 gene mutations were studied in lung adenocarcinoma patients. LOHs were relatively common, ranging from 24% at chromosome 10p to 55% at chromosome 17p13. KRAS2 mutations at codon 12 were present in 26% of cases, were more common in male than in female patients and were associated with a smoking habit. No association between LOH at any site and clinical stage or survival rate was found. On the other hand, we observed a trend between the presence of any type of KRAS2 mutations and poor survival. Analysis of specific KRAS2 mutations showed a strong effect of Asp (GAT) and Val (GTT) mutations, resulting in a very poor survival compared with wild type group, whereas the most common mutation (Cys, TGT) was not associated with prognosis. Our results indicate the importance of specific activating mutations of the KRAS2 gene as genetic markers of clinical outcome for patients with lung adenocarcinoma.

Adenocarcinoma↗
PubMed1998

Full activation of MEN2B mutant RET by an additional MEN2A mutation or by ligand GDNF stimulation.

Germline mutations of RET gene, encoding a receptor tyrosine kinase, have been associated with the MEN2A and MEN2B inherited cancer syndromes. In MEN2A mutations affecting cysteine residues in the extracellular domain of the receptor cause constitutive activation of the tyrosine kinase by the formation of disulfide-bonded homodimers. In MEN2B a single mutation in the tyrosine kinase domain (Met918Thr) has been identified. This mutation does not lead to dimer formation, but has been shown (both biologically and biochemically) to cause ligand-independent activation of the Ret protein, but to a lesser extent than MEN2A mutations. Intramolecular activation by cis-autophosphorylation of RetMEN2B monomers has been proposed as a model for activation, although alternative mechanisms can be envisaged. Here we show that the activity of RetMEN2B can be increased by stable dimerization of the receptor. Dimerization was achieved experimentally by constructing a double mutant receptor with a MEN2A mutation (Cys634Arg) in addition to the MEN2B mutation, and by chronic exposure of RetMEN2B-expressing cells to the Ret ligand GDNF. In both cases full activation of RetMEN2B, measured by 'in vitro' transfection assays and biochemical parameters, was seen. These results indicate that the MEN2B phenotype could be influenced by the tissue distribution or concentration of Ret ligand(s).

3T3 Cells↗
PubMed1998

Role of the TFG N-terminus and coiled-coil domain in the transforming activity of the thyroid TRK-T3 oncogene.

The thyroid TRK-T3 oncogene results from the fusion of the tyrosine kinase (TK) domain of NTRK1 (one of the receptors for the Nerve Growth Factor) on chromosome 1 to sequences of a novel gene, TFG, on chromosome 3. The 68 kDa TRK-T3 fusion oncoprotein displays a constitutive tyrosine kinase activity resulting in its capability to transform mouse NIH3T3 cells. The TFG portion of TRK-T3 contains a coiled-coil domain most likely responsible for the constitutive, ligand-independent activation of the receptor tyrosine kinase activity. We have previously shown that TRK-T3 oncoprotein forms, in vivo, complexes of three or four molecules. By mean of different experimental approaches, we show here that TRK-T3 activity depends on oligomers formation. In addition, the analysis of different TRK-T3 mutants indicates that the TFG coiled-coil domain and its N-terminal region are both required for the activation and the fully transforming activity of the TRK-T3 oncoprotein, although, most likely, they play a role in different steps of the transforming process. The deletion of the coiled-coil domain abrogates the oligomers formation leading to a constitutive activation; the deletion of the N-terminal region, although not affecting phosphorylation and complexes formation, abrogates transformation, thus suggesting a role in cellular localization and/or interaction with substrata.

3T3 Cells↗
PubMed1998

Molecular abnormalities in liposarcoma: role of MDM2 and CDK4-containing amplicons at 12q13-22.

It has recently been shown that mdm2 overexpression with stabilization of p53 represents a characteristic of retroperitoneal well-differentiated-dedifferentiated, here renamed evolved (WD-E), liposarcomas at the immunocytochemical, molecular, and cytogenetic level. This make-up appears to be confined to half the cases in non-retroperitoneal well-differentiated liposarcomas. Since in different tumours MDM2 amplification involves amplicons encompassing flanking genes, such as CDK4, the possibility was investigated that in these tumours, CDK4 could act as an alternative or additional gene involved in the transformation mechanism. Forty-one retroperitoneal (R)/non-retroperitoneal (NR) well-differentiated-dedifferentiated (WD-DD) and 33 myxoid/round cell liposarcomas were reanalysed by immunocytochemical, molecular (nine cases) and fluorescence in situ hybridization (FISH) (one case) techniques. The results showed that all but one R WD-E cases carried the mdm2+, p53+, cdk4+ immunophenotype. In NR-WD liposarcomas, this immunophenotype was shared in five cases and the remainder showed mdm2+, p53-, cdk4+ in four and mdm2-, p53-, cdk4+ in one case, showing ring chromosomes by FISH analysis. TP53 mutations are confirmed to be closely correlated with NR-DD liposarcomas and no CDK4 involvement was found in the myxoid/round cell liposarcoma group. As well as confirming the synergistic effect of MDM2 and CDK4, these results are consistent with the concept that amplicon(s) excluding MDM2 may contribute to transformation and support a role of CDK4 in opposing p53 function, particularly in NR WD liposarcoma.

Blotting, Southern↗
PubMed1998

A novel EWS-ERG rearrangement generating two hybrid mRNAs in a peripheral primitive neuroectodermal tumour (pPNET) with a t(15;22) translocation.

The occurrence of a t(15;22) translocation in a peripheral primitive neuroectodermal tumour (pPNET) has been previously reported. Molecular examination revealed the presence in tumour mRNA of two hybrid transcripts containing the 5' portion of the EWS gene fused to the 3' portion of the ERG gene. Sequence analyses indicated that both aberrant mRNAs most likely originated from the same rearrangement, which produced different hybrid isoforms due to the presence of an alternatively spliced exon in the ERG gene. To the authors' knowledge, this is the first report of the detection of two hybrid EWS-ERG mRNAs within the same tumour.

Adult↗
PubMed1998

Rearrangements of RET and NTRK1 tyrosine kinase receptors in papillary thyroid carcinomas.

A combined cytogenetic and molecular analysis of thyroid tumours has indicated that these neoplasms might represent a significant model for analysing human epithelial cell multi-step cancerogenesis. Thyroid tumours comprise a broad spectrum of lesions with different phenotypes and variable biological and clinical behaviour. Molecular analysis has detected specific genetic alterations in these different tumour types. In particular, the well-differentiated carcinomas of the papillary type are characterised by the activation of the tyrosine kinase receptors (TKRs) RET and NTRK1 proto-oncogenes. Cytogenetic analysis of these tumours has contributed to defining the chromosomal mechanisms leading to the TKRs' oncogenic activation. The results have shown that, in the majority of the cases, intra-chromosomal inversions of chromosome 10 and of chromosome 1 lead to the formation of RET-derived and NTRK1-derived oncogenes, respectively. Exposure to ionizing radiation is associated with papillary carcinomas, and RET activation has been suggested to be related to this event. All these findings are contributing to the definition of genetic and environmental factors relevant to the pathogenesis of thyroid tumours. Moreover, the molecular characterisation of specific genetic lesions could provide significant information about the association between ionising radiation and RET oncogene activation.

Adolescent↗
PubMed1998

Genetic mapping of cancer susceptibility/resistance loci in the mouse.

Genetic linkage experiments using crosses between mouse inbred strains with an inherited predisposition and resistance to lung cancer make it possible to investigate the genetics of the complex inheritance of susceptibility and resistance to lung cancer. We have previously mapped a major locus (pulmonary adenoma susceptibility 1, Pas1) affecting inherited predisposition to lung cancer in mice onto chromosome 6, near Kras2. Appropriate crosses that include Pas1/+ mice provide a model system for identifying loci that can modify the lung cancer predisposition phenotype caused by Pas1. Using this approach, we mapped the pulmonary adenoma resistance 1 (Par1) locus on to mouse chromosome 11; this locus selectively inhibits lung tumor development in Pas1/+ animals and therefore behaves like a modulator gene of Pas1. More recently, we have mapped lung tumor modifier loci specifically affecting the initiation and progression of lung cancer. Thus experimental models provide an essential tool for the mapping of lung cancer susceptibility/resistance genes and for the subsequent cloning of candidate genes.

Adenoma↗
PubMed1998

No evidence of WT1 involvement in a Burkitt's lymphoma in a patient with Denys-Drash syndrome.

BACKGROUND: We previously reported the case of a patient affected with Denys-Drash syndrome (DDS), who developed disseminated EBV-related Burkitt's lymphoma (BL) after kidney transplantation. Here, we describe the molecular characterisation of the WT1 gene in the constitutional and tumour DNA of this patient. PATIENTS AND METHODS: WT1 exons 2 to 10 were sequenced in constitutional and tumour DNAs. By Southern blotting the latter was also investigated for the presence of gene rearrangements. Gene expression analysis in tumour cells was performed by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: A germline missense mutation affecting one of the zinc finger domains of the gene, and previously reported in other DDS cases, was observed. No alterations of the constitutionally wild-type WT1 allele and no expression of the gene were observed in BL cells. A small group of BLs from other paediatric patients showed a variable expression of WT1. CONCLUSIONS: Our findings indicate that WT1 is unlikely to be involved in the onset of BL in our case. However, a possible role of the gene in at least a subset of these lymphoproliferative diseases may be suggested.

Abnormalities, Multiple↗
PubMed1998

Detection of TP53 mutation, loss of heterozygosity and DNA content in fine-needle aspirates of breast carcinoma.

Recent preclinical and clinical data suggest that TP53 status and TP53 mutations may be important in determining tumour aggressiveness and therapy response. In this study we investigate the feasibility of a structural and quantitative analysis of TP53 on fine-needle aspiration (FNA) material obtained from 31 consecutive female patients with breast carcinoma, enrolled in a primary chemotherapy protocol. Tumours were screened for p53 protein overexpression and TP53 mutations (exons 5-8) using immunocytochemistry, polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing analyses, and finally using fluorescence in situ hybridization (FISH) analysis. Positive nuclear staining was identified in six cases whereas mutations were detected in nine. Although the immunoreactive pattern fitted fully with the characterized TP53 mutation type, the considerable number of null p53 mutations (i.e. four) coupled with the lack of information regarding the localization of TP53 mutations make immunocytochemistry an inadequate indicator of TP53 function deregulation. Combining molecular and FISH analyses, we detected three cases with TP53 deletion and one case with deletion and mutation. Finally, DNA static-image analysis performed on 29 cases showed aneuploidy in 26 cases, which included all TP53-mutated cases. The present results show that FNA may assist clinical decisions by allowing the evaluation of a variety of biological parameters relevant for prognosis and treatment planning.

Adult↗
PubMed1998

Mutations of adenomatous polyposis coli (APC) gene are uncommon in sporadic desmoid tumours.

Desmoids are locally aggressive, non-metastasizing soft-tissue tumours, whose aetiology is still unclear. In patients affected with familial adenomatous polyposis (FAP), the incidence of desmoids is much higher than in the general population. The APC gene, which is responsible for FAP, is involved in the development of desmoids associated with this syndrome. In this study 16 sporadic and four FAP-related desmoids were analysed in order to investigate the possible involvement of APC in non-syndromic cases also. The 5' end (exons 1-11) and the coding portion of exon 15 of APC were screened using the in vitro synthesized-protein assay (IVSP). Exons 5, 6, 8-14, and a region of exon 15 spanning codons 1036-1634 were investigated by single-strand conformation polymorphism (SSCP) analysis. APC germline mutations were identified in all FAP patients, but not in sporadic cases. Somatic mutations were found in three FAP-associated desmoids (75%) and two sporadic tumours (12.5%). In one of the latter cases, both alleles were affected. These findings indicate a limited role of the gene in the development of desmoid tumours outside FAP.

Adenomatous Polyposis Coli↗
PubMed1998

Rapid assessment of replication error phenotype in gastric cancer.

Forty gastric tumors were investigated for microsatellite instability at the D2S119 and L-myc loci. These tumors and 143 other gastrointestinal cancers were previously analyzed for instability at several different microsatellites. By evaluating previous and present results, repeated sequences were selected that frequently underwent replication errors (RERs). To coamplify these sequences, the following multiplex polymerase chain reactions (PCRs) were performed: 1) D2S119/L-myc/D18S59; 2) D2S119/L-myc/D3S1076; and 3) D2S177/L-myc/BAT-RII. Therefore, the 40 gastric tumors in the present survey were rescreened using multiplex PCRs. Each multiplex allowed detection of nearly all RER+ tumors (80% for multiplex 3 and 87% for multiplexes 1 and 2) that had been previously identified by amplifying 9 different loci with independent reactions. Moreover, for multiplexes 1 and 2, the size differences between normal and RER alleles were sufficient to be detected by electrophoresis on conventional polyacrylamide gels after DNA staining with ethidium bromide. This approach allows a rapid and easy assessment of RER phenotype in gastric tumors.

Chromosomes, Human, Pair 2↗
PubMed1998

Characterization of ten novel and 13 recurring BRCA1 and BRCA2 germline mutations in Italian breast and/or ovarian carcinoma patients. Mutations in brief no. 178. Online.

Germline mutations in the BRCA1 and BRCA2 genes are associated with approximately 80% of families with a high incidence of breast and/or ovarian cancers (OMIM database reference numbers: 113705, 600185). Furthermore, constitutional mutations in the these genes have been reported in women with early-onset breast carcinoma and without family history of cancer. We analyzed by protein truncation test (PTT) and single strand conformation polymorphism (SSCP) followed by sequence analysis, BRCA1 exons 11 and 20 and BRCA2 exons 10 and 11 in 142 Italian cancer patients. These included six male breast cancer cases, 61 women with breast carcinoma diagnosed before 36 years old and selected independently of family history of breast cancer and 75 familial breast and/or ovarian cancer patients. In a previous report, we described 11 different BRCA1 mutations in a subset of 70 cases. Here, we report the characterization of 23 additional mutations, 14 in BRCA1 and 9 in BRCA2, subsequently identified. Ten mutations were not previously described, while the other 13 were recurrent. Of the 61 women with early-onset breast cancer, 11 carried a germline mutation in BRCA1 (18.0%) and four in BRCA2 (6.6%). These frequencies indicate that BRCA1/BRCA2 genetic tests should be advised to women with breast cancer diagnosed at early age, independently of family history of cancer.

BRCA1 Protein↗
PubMed1998

Analysis of the retinoic acid receptor alpha gene as a candidate for the pulmonary adenoma resistance 1 gene.

The retinoic acid receptor alpha (Rara) gene, which maps in the same region as the pulmonary adenoma resistance (Par1) locus on mouse chromosome 11 (Manenti G et al., Nature Genet 12:455-457, 1996), was tested as a candidate gene for Par1. We report here the analysis of loss of heterozygosity, nucleotide sequence comparison, gene expression, and biochemical activity of the Rara gene from the Mus spretus(Par1/+) and A/J (Par1/-) mouse strains. The two Rara alleles were distinguished by two amino-acid variations but had similar biochemical activity and expression levels, leading to the exclusion of Rara as a candidate Par1 gene.

Adenoma↗
PubMed1998

RET/NTRK1 rearrangements in thyroid gland tumors of the papillary carcinoma family: correlation with clinicopathological features.

The papillary carcinoma family (PCF) of thyroid tumors includes a wide variety of neoplastic entities regarded as well-differentiated, poorly differentiated, and undifferentiated papillary thyroid carcinomas. Recent studies have established the presence of alternative oncogenic rearrangements of the RET and NTRK1 genes in a consistent fraction (< or = 50%) of papillary thyroid tumors. RET oncogenic rearrangements are also very frequent (approximately 60%) in Chernobyl radiation-associated papillary thyroid neoplasias, which show an increased aggressiveness in terms of pathological stage at disease onset. These observations prompted us to study the relationship between the presence or absence of RET and NTRK1 oncogenes and the clinicopathological features (age, sex, histopathology, and pTNMC2 staging) of 76 consecutive, non-radiation-related tumors of the PCF. As previously reported, statistical univariate analysis revealed a correlation between the combination of RET and NTRK1 (RET/NTRK1) positivity and young age of patients at diagnosis. In addition, a significant association was found between RET/NTRK1 positivity and locally advanced stage of disease at presentation (pT4: P < 0.015). The multivariate analysis confirmed that RET/NTRK1 activation parallels an unfavorable disease presentation, which may correlate with a less favorable disease outcome. Furthermore, within the PCF, the frequency of RET/NTRK1 positivity was not influenced by the different neoplastic subtypes or the tumor versus degree of differentiation.

Adolescent↗
PubMed1997

Replacement of Fhit in cancer cells suppresses tumorigenicity.

The candidate tumor suppressor gene, FHIT, encompasses the common human chromosomal fragile site at 3p14.2, the hereditary renal cancer translocation breakpoint, and cancer cell homozygous deletions. Fhit hydrolyzes dinucleotide 5',5"'-P1,P3-triphosphate in vitro and mutation of a central histidine abolishes hydrolase activity. To study Fhit function, wild-type and mutant FHIT genes were transfected into cancer cell lines that lacked endogenous Fhit. No consistent effect of exogenous Fhit on growth in culture was observed, but Fhit and hydrolase "dead" Fhit mutant proteins suppressed tumorigenicity in nude mice, indicating that 5',5"'-P1, P3-triphosphate hydrolysis is not required for tumor suppression.

Acid Anhydride Hydrolases↗