| 1. |
- Samuelson, Emma, 1974, et al.
(författare)
-
Absence of Ras mutations in rat DMBA-induced mammary tumors.
- 2009
-
Ingår i: Molecular carcinogenesis. - : Wiley. - 1098-2744 .- 0899-1987. ; 48:2, s. 150-5
-
Tidskriftsartikel (refereegranskat)abstract
- Animal cancer models reduce genetic background heterogeneity and thus, may facilitate identification and analysis of specific genetic aberrations in tumor cells. Rat and human mammary glands have high similarity in physiology and show comparable hormone responsiveness. Thus, spontaneous and carcinogen (e.g., NMU and DMBA)-induced rat mammary models are valuable tools for genetic studies of breast cancer. In NMU-induced rat mammary tumors, activating mutations in Hras codon 12 have frequently been reported and are supposed to contribute to the mammary carcinogenic process. Involvement of Ras mutations in DMBA-induced tumors is less clear. In the present study we investigated the mutation status of the three Ras genes, Hras, Kras, and Nras, in DMBA-induced rat mammary tumors. We examined codons 12, 13, and 61 of all three genes for mutations in 71 tumors using direct sequencing method that in experimental conditions is sensitive enough to detect single nucleotide mutations even when present in only 25% of the test sample. No activating Ras gene mutation was found. Thus, in contrast to NMU-induced rat mammary tumor, tumorigenesis in DMBA-induced rat mammary tumors seems to be independent on activating mutations in the Ras genes. Our finding suggests that the genetic pathways selected in mammary tumor development are influenced by and perhaps dependent on the identity of the inducing agent, again emphasizing the importance of tumor etiology on the genetic changes in the tumor cells.
|
|
| 2. |
|
|
| 3. |
- Samuelson, Emma, et al.
(författare)
-
Molecular classification of spontaneous endometrial adenocarcinomas in BDII rats
- 2009
-
Ingår i: Endocrine-Related Cancer. - : Bioscientifica. - 1351-0088 .- 1479-6821. ; 16:1, s. 99-111
-
Tidskriftsartikel (refereegranskat)abstract
- Female rats of the BDII/Han inbred strain are prone to spontaneously develop endometrial carcinomas (EC) that in cell biology and pathogenesis are very similar to those of human. Human EC are classified into two major groups: Type I displays endometroid histology, is hormone-dependent, and characterized by frequent microsatellite instability and PTEN, K-RAS, and CTNNB1 (β-Catenin) mutations; Type II shows non-endometrioid histology, is hormone-unrelated, displays recurrent TP53 mutation, CDKN2A (P16) inactivation, over-expression of ERBB2 (Her2/neu), and reduced CDH1 (Cadherin 1 or E-Cadherin) expression. However, many human EC have overlapping clinical, morphologic, immunohistochemical, and molecular features of types I and II. The EC developed in BDII rats can be related to type I tumors, since they are hormone-related and histologically from endometrioid type. Here, we combined gene sequencing (Pten, Ifr1, and Ctnnb1) and real-time gene expression analysis (Pten, Cdh1, P16, Erbb2, Ctnnb1, Tp53, and Irf1) to further characterize molecular alterations in this tumor model with respect to different subtypes of EC in humans. No mutation in Pten and Ctnnb1 was detected, whereas three tumors displayed sequence aberrations of the Irf1 gene. Significant down regulation of Pten, Cdh1, p16, Erbb2, and Ctnnb1 gene products was found in the tumors. In conclusion, our data suggest that molecular features of spontaneous EC in BDII rats can be related to higher-grade human type I tumors and thus, this model represents an excellent experimental tool for research on this malignancy in human.
|
|
| 4. |
- Behboudi, Afrouz, 1967, et al.
(författare)
-
Molecular classification of mucoepidermoid carcinomas-prognostic significance of the MECT1-MAML2 fusion oncogene.
- 2006
-
Ingår i: Genes, chromosomes & cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 45:5, s. 470-81
-
Tidskriftsartikel (refereegranskat)abstract
- Mucoepidermoid carcinomas (MECs) of the salivary and bronchial glands are characterized by a recurrent t(11;19)(q21;p13) translocation resulting in a MECT1-MAML2 fusion in which the CREB-binding domain of the CREB coactivator MECT1 (also known as CRTC1, TORC1 or WAMTP1) is fused to the transactivation domain of the Notch coactivator MAML2. To gain further insights into the molecular pathogenesis of MECs, we cytogenetically and molecularly characterized a series of 29 MECs. A t(11;19) and/or an MECT1-MAML2 fusion was detected in more than 55% of the tumors. Several cases with cryptic rearrangements that resulted in gene fusions were detected. In fusion-negative MECs, the most common aberration was a single or multiple trisomies. Western blot and immunohistochemical studies demonstrated that the MECT1-MAML2 fusion protein was expressed in all MEC-specific cell types. In addition, cotransfection experiments showed that the fusion protein colocalized with CREB in homogeneously distributed nuclear granules. Analyses of potential downstream targets of the fusion revealed differential expression of the cAMP/CREB (FLT1 and NR4A2) and Notch (HES1 and HES5) target genes in fusion-positive and fusion-negative MECs. Moreover, clinical follow-up studies revealed that fusion-positive patients had a significantly lower risk of local recurrence, metastases, or tumor-related death compared to fusion-negative patients (P = 0.0012). When considering tumor-related deaths only, the estimated median survival for fusion-positive patients was greater than 10 years compared to 1.6 years for fusion-negative patients. These findings suggest that molecularly classifying MECs on the basis of an MECT1-MAML2 fusion is histopathologically and clinically relevant and that the fusion is a useful marker in predicting the biological behavior of MECs.
|
|
| 5. |
- Behboudi, Afrouz, 1967, et al.
(författare)
-
Clear cell hidradenoma of the skin-a third tumor type with a t(11;19)--associated TORC1-MAML2 gene fusion.
- 2005
-
Ingår i: Genes, chromosomes & cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 43:2, s. 202-5
-
Tidskriftsartikel (refereegranskat)abstract
- Recent studies have shown that the t(11;19)(q21;p13) translocation in mucoepidermoid carcinomas and benign Warthin's tumors results in a fusion of the N-terminal CREB-binding domain of the cAMP coactivator TORC1 (a.k.a. MECT1 and WAMTP1) to the Notch coactivator MAML2. Here we show that a third tumor type, clear cell hidradenoma of the skin, also expresses this gene fusion. RT-PCR analysis of a clear cell hidradenoma with a t(11;19)(q21;p13) translocation revealed expression of a TORC1-MAML2 fusion transcript consisting of exon 1 of TORC1 fused to exons 2-5 of MAML2. Because the fusion was only detected in a single case, the frequency of this aberration in clear cell hidradenomas remains unknown. These results demonstrate that the t(11;19) in mucoepidermoid carcinoma, Warthin's tumor, and clear cell hidradenoma targets the same genes and results in identical gene fusions, indicating that at least subgroups of these glandular tumors evolve through activation of the same molecular pathways.
|
|
| 6. |
- Bergman, Annika, et al.
(författare)
-
No germline mutations in supposed tumour suppressor genes SAFB1 and SAFB2 in familial breast cancer with linkage to 19p.
- 2008
-
Ingår i: BMC Medical Genetics. - : BioMed Central. - 1471-2350. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The scaffold attachment factor B1 and B2 genes, SAFB1/SAFB2 (both located on chromosome 19p13.3) have recently been suggested as tumour suppressor genes involved in breast cancer development. The assumption was based on functional properties of the two genes and loss of heterozygosity of intragenic markers in breast tumours further strengthened the postulated hypothesis. In addition, linkage studies in Swedish breast cancer families also indicate the presence of a susceptibility gene for breast cancer at the 19p locus. Somatic mutations in SAFB1/SAFB2 have been detected in breast tumours, but to our knowledge no studies on germline mutations have been reported. In this study we investigated the possible involvement of SAFB1/SAFB2 on familiar breast cancer by inherited mutations in either of the two genes.RESULTS: Mutation analysis in families showing linkage to the SAFB1/2 locus was performed by DNA sequencing. The complete coding sequence of the two genes SAFB1 and SAFB2 was analyzed in germline DNA from 31 affected women. No missense or frameshift mutations were detected. One polymorphism was found in SAFB1 and eight polymorphisms were detected in SAFB2. MLPA-anlysis showed that both alleles of the two genes were preserved which excludes gene inactivation by large deletions.CONCLUSION: SAFB1 and SAFB2 are not likely to be causative of the hereditary breast cancer syndrome in west Swedish breast cancer families.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Sjöling, Åsa, 1968, et al.
(författare)
-
Assessment of allele dosage at polymorphic microsatellite loci displaying allelic imbalance in tumors by means of quantitative competitive-polymerase chain reaction.
- 2005
-
Ingår i: Cancer genetics and cytogenetics. - : Elsevier BV. - 0165-4608 .- 1873-4456. ; 157:2, s. 97-103
-
Tidskriftsartikel (refereegranskat)abstract
- Analysis of allelic imbalance at polymorphic marker loci is usually employed to identify chromosomal regions affected by recurrent aberrations in tumor genomes. Such regions are likely to harbor genes involved in the onset and/or progression of cancer. Although often used to identify regions of loss of heterozygosity caused by deletions/rearrangements near tumor suppressor gene loci, allelic imbalance can also reflect regional amplification, indicating the presence of oncogenes. It is difficult to tell these two situations apart after ordinary polymerase chain reaction (PCR), but here we describe a method that distinguishes allelic loss from allelic gain. The level of allelic imbalance was determined by quantitative PCR (QPCR) in the presence of an internal control DNA that displayed a third allele at the locus studied. To validate the efficiency of allele quantitation, we analyzed an amplified region in a set of rat fibrosarcomas. In four tumor samples with amplification of the Met oncogene, we could show with QPCR that there was amplification of one of the alleles at a microsatellite marker located close to Met. QPCR may be useful for cancer studies because experiments may be predesigned for using either suitable microsatellite markers or the abundant and polymorphic poly-A tails of rodent identifier sequences.
|
|
| 10. |
- Behboudi, Afrouz, Professor, 1967-, et al.
(författare)
-
CRTC1 (CREB regulated transcription coactivator 1)
- 2006
-
Ingår i: Atlas of Genetics and Cytogenetics in Oncology and Haematology. - : Atlas of Genetics and Cytogenetics in Oncology and Haematology. - 1768-3262. ; :2006-05-01
-
Forskningsöversikt (refereegranskat)
|
|
