1
|
In or Out? New Insights on Exon Recognition through Splice-Site Interdependency. Int J Mol Sci 2020; 21:ijms21072300. [PMID: 32225107 PMCID: PMC7177576 DOI: 10.3390/ijms21072300] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/13/2020] [Accepted: 03/23/2020] [Indexed: 01/02/2023] Open
Abstract
Noncanonical splice-site mutations are an important cause of inherited diseases. Based on in vitro and stem-cell-based studies, some splice-site variants show a stronger splice defect than expected based on their predicted effects, suggesting that other sequence motifs influence the outcome. We investigated whether splice defects due to human-inherited-disease-associated variants in noncanonical splice-site sequences in ABCA4, DMD, and TMC1 could be rescued by strengthening the splice site on the other side of the exon. Noncanonical 5′- and 3′-splice-site variants were selected. Rescue variants were introduced based on an increase in predicted splice-site strength, and the effects of these variants were analyzed using in vitro splice assays in HEK293T cells. Exon skipping due to five variants in noncanonical splice sites of exons in ABCA4, DMD, and TMC1 could be partially or completely rescued by increasing the predicted strengths of the other splice site of the same exon. We named this mechanism “splicing interdependency”, and it is likely based on exon recognition by splicing machinery. Awareness of this interdependency is of importance in the classification of noncanonical splice-site variants associated with disease and may open new opportunities for treatments.
Collapse
|
2
|
Muller D, Rouleau E, Schultz I, Caputo S, Lefol C, Bièche I, Caron O, Noguès C, Limacher JM, Demange L, Lidereau R, Fricker JP, Abecassis J. An entire exon 3 germ-line rearrangement in the BRCA2 gene: pathogenic relevance of exon 3 deletion in breast cancer predisposition. BMC MEDICAL GENETICS 2011; 12:121. [PMID: 21939546 PMCID: PMC3198910 DOI: 10.1186/1471-2350-12-121] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022]
Abstract
Background Germ-line mutations in the BRCA1 and BRCA2 genes are major contributors to hereditary breast/ovarian cancer. Large rearrangements are less frequent in the BRCA2 gene than in BRCA1. We report, here, the first total deletion of exon 3 in the BRCA2 gene that was detected during screening of 2058 index cases from breast/ovarian cancer families for BRCA2 large rearrangements. Deletion of exon 3, which is in phase, does not alter the reading frame. Low levels of alternative transcripts lacking exon 3 (Δ3 delta3 transcript) have been reported in normal tissues, which raises the question whether deletion of exon 3 is pathogenic. Methods Large BRCA2 rearrangements were analysed by QMPSF (Quantitative Multiplex PCR of Short Fluorescent Fragments) or MLPA (Multiplex Ligation-Dependent Probe Amplification). The exon 3 deletion was characterized with a "zoom-in" dedicated CGH array to the BRCA2 gene and sequencing. To determine the effect of exon 3 deletion and assess its pathogenic effect, three methods of transcript quantification were used: fragment analysis of FAM-labelled PCR products, specific allelic expression using an intron 2 polymorphism and competitive quantitative RT-PCR. Results Large rearrangements of BRCA2 were detected in six index cases out of 2058 tested (3% of all deleterious BRCA2 mutations). This study reports the first large rearrangement of the BRCA2 gene that includes all of exon 3 and leads to an in frame deletion of exon 3 at the transcriptional level. Thirty five variants in exon 3 and junction regions of BRCA2 are also reported, that contribute to the interpretation of the pathogenicity of the deletion. The quantitative approaches showed that there are three classes of delta3 BRCA2 transcripts (low, moderate and exclusive). Exclusive expression of the delta3 transcript by the mutant allele and segregation data provide evidence for a causal effect of the exon 3 deletion. Conclusion This paper highlights that large rearrangements and total deletion of exon 3 in the BRCA2 gene could contribute to hereditary breast and/or ovarian cancer. In addition, our findings suggest that, to interpret the pathogenic effect of any variants of exon 3, both accurate transcript quantification and co-segregation analysis are required.
Collapse
Affiliation(s)
- Danièle Muller
- Division of oncogenetic, Department of Biology and Pathology, Regional Cancer Centre Paul Strauss, BP30042, 67065 Strasbourg, France.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Treatment with olaparib in a patient with PTEN-deficient endometrioid endometrial cancer. Nat Rev Clin Oncol 2011; 8:302-6. [PMID: 21468130 DOI: 10.1038/nrclinonc.2011.42] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND A 58-year-old woman presented with metastatic endometrioid endometrial adenocarcinoma after being previously treated with surgery and adjuvant radiotherapy for early-stage endometrial cancer. She had received several lines of chemotherapy for multiple relapses over 9 years and displayed a profound sensitivity to platinum-containing regimens. INVESTIGATION CT scans demonstrated progressing liver, lung and peritoneal metastases and MRI detected multiple intracerebral metastases. DIAGNOSIS New brain metastases secondary to progressive endometrioid endometrial carcinoma. MANAGEMENT On the basis of her sensitivity to repeated platinum treatment she was treated with the oral poly(ADP)-ribose polymerase (PARP) 1 inhibitor olaparib as part of a phase I trial. Repeat MRI scan at week 10 of treatment showed a significant reduction in the size of the brain metastases without steroid treatment or radiotherapy and the patient reported subjective improvement in tumor-related symptoms. After 8 months of olaparib treatment the patient developed objective disease progression. The tumor biopsy was negative for somatic BRCA1 and BRCA2 mutations, but displayed loss of PTEN, which has been suggested to be another predictive marker for sensitivity to PARP inhibitors. The patient remained alive for 10 months after completing olaparib, having gone on to derive further clinical benefit from repeat exposure to platinum-based therapy.
Collapse
|
4
|
Dedes KJ, Wetterskog D, Mendes-Pereira AM, Natrajan R, Lambros MB, Geyer FC, Vatcheva R, Savage K, Mackay A, Lord CJ, Ashworth A, Reis-Filho JS. PTEN deficiency in endometrioid endometrial adenocarcinomas predicts sensitivity to PARP inhibitors. Sci Transl Med 2011; 2:53ra75. [PMID: 20944090 DOI: 10.1126/scitranslmed.3001538] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
PTEN (phosphatase and tensin homolog) loss of function is the most common genetic aberration in endometrioid endometrial carcinomas. In addition to its well-described role in cell signaling, PTEN is involved in the maintenance of genomic stability. Loss of PTEN function causes defects in repair of DNA double-strand breaks by homologous recombination and, therefore, sensitizes cells to inhibition of the poly(adenosine diphosphate ribose) polymerase (PARP). Here, we determined the PTEN status of eight endometrioid endometrial carcinoma cell lines and correlated it with in vitro sensitivity to the PARP inhibitor KU0058948. PTEN-deficient cells showed a significantly greater sensitivity to KU0058948 than the two endometrioid endometrial carcinoma cell lines with wild-type PTEN. The cell lines lacking PTEN expression were unable to elicit a homologous recombination damage response as assayed by RAD51 focus function (a marker of competent homologous recombination DNA repair) upon irradiation and treatment with PARP inhibitors. PTEN silencing in PTEN wild-type Hec-1b cells resulted in reduced RAD51 foci formation after DNA damage and increased sensitivity to PARP inhibition. PTEN reexpression in PTEN-null cell lines resulted in enhanced RAD51 foci formation and in relative resistance to KU0058948. Given that up to 80% of endometrioid endometrial cancers lack PTEN expression, our results suggest that PARP inhibitors may be therapeutically useful for a subset of endometrioid endometrial cancers.
Collapse
Affiliation(s)
- Konstantin J Dedes
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, SW3 6JB London, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Double strand break repair components are frequent targets of microsatellite instability in endometrial cancer. Eur J Cancer 2010; 46:2821-7. [DOI: 10.1016/j.ejca.2010.06.116] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 06/18/2010] [Indexed: 11/22/2022]
|
6
|
Diez O, Gutiérrez-Enríquez S, Masas M, Tenés A, Yagüe C, Arcusa A, Llort G. Identification of a new complex deleterious mutation in exon 18 of the BRCA2 gene in a hereditary male/female breast cancer family. Breast Cancer Res Treat 2010; 123:587-90. [PMID: 20232139 DOI: 10.1007/s10549-010-0830-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 02/27/2010] [Indexed: 11/30/2022]
Abstract
We report a novel complex mutation that consists of a deletion of 12 bp and an insertion of 2 bp (c.8402_8413del12ins2bp) in the exon 18 of the BRCA2 gene. This is a frameshift mutation that causes a disruption of the translational reading frame resulting in a stop codon downstream in the 2729 position of the BRCA2 protein. The mutation was present in a Spanish hereditary male/female breast cancer family.
Collapse
Affiliation(s)
- Orland Diez
- Oncogenetics Laboratory, University Hospital Vall d'Hebron, 08035, Barcelona, Spain.
| | | | | | | | | | | | | |
Collapse
|
7
|
Caution should be taken in the methodology used to confirm c.156_157insAlu BRCA2 mutation. Breast Cancer Res Treat 2008; 116:617-8. [PMID: 18633700 DOI: 10.1007/s10549-008-0124-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 10/21/2022]
|
8
|
Abdel-Rahman WM, Knuutila S, Peltomäki P, Harrison DJ, Bader SA. Truncation of MBD4 predisposes to reciprocal chromosomal translocations and alters the response to therapeutic agents in colon cancer cells. DNA Repair (Amst) 2007; 7:321-8. [PMID: 18162445 DOI: 10.1016/j.dnarep.2007.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 10/18/2007] [Accepted: 11/06/2007] [Indexed: 01/27/2023]
Abstract
We previously identified a novel genomic instability phenotype of multiple reciprocal chromosomal translocations in a MLH1-defective, microsatellite unstable (MSI) colon cancer cell line (HCA7) and, further, showed that it was unlikely to be directly caused by the mismatch repair (MMR) defect in this cell line. To gain insight into the molecular basis to this novel translocation phenotype, we examined coding and splice-site nucleotide repeat tracts in DNA repair genes for mutations by direct sequencing together with RT-PCR expression analysis of the associated transcript. The material was a selected panel of 8 MSI cell lines including HCA7. A strong candidate identified through this approach was MBD4 as it showed a homozygous truncating mutation associated with substantial loss of the transcript in HCA7 not seen in the other lines. In previous published studies, heterozygous MBD4 mutations were observed in up to 89% of sporadic MSI microdissected colon tumor foci. Using MFISH, we show that over-expression of the truncated MBD4 (+MBD4(tru)) in DLD1, a MSH6 defective, MSI human colon carcinoma cell line predisposed these cells to acquire structural chromosomal rearrangements including multiple reciprocal translocations after irradiation, reminiscent of those seen in HCA7. We also show that over-expression of MBD4(tru) in DLD1 alters the colony survival after exposure to cisplatin or etoposide. These data suggest a wide role for MBD4 in DNA damage response and maintaining chromosomal stability.
Collapse
|
9
|
Díez O, Gutiérrez-Enríquez S, Ramón y Cajal T, Alonso C, Balmaña J, Llort G. Caution should be used when interpreting alterations affecting the exon 3 of the BRCA2 gene in breast/ovarian cancer families. J Clin Oncol 2007; 25:5035-6; author reply 5036-8. [PMID: 17971607 DOI: 10.1200/jco.2007.13.4346] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
10
|
Affiliation(s)
- Patrícia M. Machado
- Molecular Biology Department, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| | - Branca M. Cavaco
- Molecular Biology Department, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| | - Rita Brandão
- Molecular Biology Department, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| | - Joana Eugénio
- Molecular Biology Department, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| | - Sidónia Santos
- Molecular Biology Department, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| | - Ana Opinião
- Breast Cancer Risk Evaluation Clinic, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| | - Fátima Vaz
- Molecular Biology Department and Breast Cancer Risk Evaluation Clinic, Instituto Português de Oncologia de Lisboa, Francisco Gentil, Portugal
| |
Collapse
|
11
|
Awadelkarim KD, Aceto G, Veschi S, Elhaj A, Morgano A, Mohamedani AA, Eltayeb EA, Abuidris D, Di Gioacchino M, Battista P, Verginelli F, Cama A, Elwali NE, Mariani-Costantini R. BRCA1 and BRCA2 status in a Central Sudanese series of breast cancer patients: interactions with genetic, ethnic and reproductive factors. Breast Cancer Res Treat 2007; 102:189-99. [PMID: 17333343 DOI: 10.1007/s10549-006-9303-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Accepted: 06/03/2006] [Indexed: 10/23/2022]
Abstract
The etiology of breast cancer in Africa is scarcely investigated. Breast cancer was responsible for 456/2,233 cancer patients (20.4%) ascertained between 1999 and 2004 at Gezira University, Central Sudan. Male breast cancer accounted for 16/456 patients (3.5%), 275/440 female patients (62.5%) were premenopausal and 150/440 cases (34%) occurred in women with > or =5 childbirths. We characterized for germline BRCA1/2 mutations a one-year series of patients (34 females, 1 male) selected by diagnosis within age 40 years or male gender. Overall 33/35 patients were found to carry 60 BRCA1/2 variants, of which 17 (28%) were novel, 22 (37%) reported in populations from various geographic areas and 21 (35%) reported worldwide. Detected variants included 5 truncating mutations, one of which (in BRCA2) was in the male patient. The 55 non-truncating variants included 3 unclassified variants predicted to affect protein product and not co-occurring with a truncating mutation in the same gene. Patients were from different tribes but AMOVA showed that most BRCA1/2 variation was within individuals (86.41%) and patients clustered independently of tribe in a phylogenetic tree. Cluster analysis based on age at cancer diagnosis and reproductive variables split female patients in two clusters that, by factor analysis, were explained by low versus high scores of the total period occupied by pregnancies and lactation. The cluster with low scores comprised all 4 patients with truncating mutations and 3 of the 4 carriers of unclassified variants predicted to affect protein product. Our findings suggest that in Central Sudan BRCA1/2 represent an important etiological factor of breast cancer in males and young women less exposed to pregnancy and lactation. Factors other than BRCA1/2 may contribute to breast cancer in young highly multiparous women who breast-fed for prolonged periods.
Collapse
Affiliation(s)
- Khalid Dafaallah Awadelkarim
- Unit of Molecular Pathology and Genomics, Center for Sciences on the Ageing, Gabriele d'Annunzio University Foundation, Via Colle dell Ara, Chieti, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
van der Heijden MS, Brody JR, Elghalbzouri-Maghrani E, Zdzienicka MZ, Kern SE. Does tumorigenesis select for or against mutations of the DNA repair-associated genes BRCA2 and MRE11?: considerations from somatic mutations in microsatellite unstable (MSI) gastrointestinal cancers. BMC Genet 2006; 7:3. [PMID: 16417627 PMCID: PMC1382246 DOI: 10.1186/1471-2156-7-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 01/17/2006] [Indexed: 11/30/2022] Open
Abstract
Background The BRCA2 and MRE11 proteins participate in the repair of double-strand DNA breaks by homologous recombination. Germline BRCA2 mutations predispose to ovarian, breast and pancreatic cancer, while a germline MRE11 mutation is associated with an ataxia telangiectasia-like disorder. Somatic mutations of BRCA2 are rare in typical sporadic cancers. In tumors having microsatellite instability (MSI), somatic truncating mutations in a poly [A] tract of BRCA2 are reported on occasion. Results We analyzed gastrointestinal MSI cancers by whole gene BRCA2 sequencing, finding heterozygous truncating mutations in seven (47%) of 15 patients. There was no cellular functional defect in RAD51 focus-formation in three heterozygously mutated lines studied, although other potential functions of the BRCA2 protein could still be affected. A prior report of mutations in primary MSI tumors affecting the IVS5-(5–15) poly [T] tract of the MRE11 gene was confirmed and extended by analysis of the genomic sequence and protein expression in MSI cancer cell lines. Statistical analysis of the published MRE11 mutation rate in MSI tumors did not provide evidence for a selective pressure favoring biallelic mutations at this repeat. Conclusion Perhaps conflicting with common suspicions, the data are not compatible with selective pressures during tumorigenesis promoting the functional loss of BRCA2 and MRE11 in MSI tumors. Instead, these data fit closely with an absence of selective pressures acting on BRCA2 and MRE11 gene status during tumorigenesis.
Collapse
Affiliation(s)
- Michiel S van der Heijden
- From the department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Jonathan R Brody
- From the department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Malgorzata Z Zdzienicka
- Department of Toxicology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Molecular Cell Genetics, Collegium Medicum, N. Copernicus University, Bydgoszcz, Poland
| | - Scott E Kern
- From the department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- From the department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| |
Collapse
|
13
|
Chen FM, Hou MF, Chang MY, Wang JY, Hsieh JS, Ou-Yang F, Huang TJ, Lin SR. High frequency of somatic missense mutation of BRCA2 in female breast cancer from Taiwan. Cancer Lett 2005; 220:177-84. [PMID: 15766593 DOI: 10.1016/j.canlet.2004.10.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 10/16/2004] [Accepted: 10/18/2004] [Indexed: 11/15/2022]
Abstract
Somatic mutation of BRCA2 has been thought to be rare in breast cancers, though common allelic deletions in the BRCA2 locus (13q12-q13) imply an important role of somatic mutation in these tumors. Reasons of the reported rare incidence could be related to very few studies focusing on the mutational analysis of BRCA2 in sporadic tumors. The mutational status of the BRCA2 gene in exon11, the largest exon harboring the RAD51 interacting BRC domains which are critical for BRCA2 function, was screened by polymerase chain reaction/single strand conformation polymorphism (PCR-SSCP) analysis followed by direct sequencing. Tumor and paired normal tissue sample from 175 patients unselected for family history or age were taken after mastectomy for breast cancer and evaluated. There were 20 mutations of BRCA2 gene in exon 11 in 15 cases (15/175, 8.6%). Most mutations we identified were point mutation (19/20, 95%), except for one nucleotide insertion. Furthermore, among these mutations, missense mutations comprised 80% (16/20) of the BRCA2 mutations. All mutations we found were novel mutation after searched in the BIC database. There were three recurrent mutations at codon 1904; and two recurrent mutations at 1907, 1936, 1937 and 1968, respectively. The mutations were associated with ductal carcinoma in situ (P=0.038) and borderline with low histological grade (P=0.072). Besides, there were three cases possessing multiple mutations in the region we studied and one of them demonstrated aggressive lymph node metastasis. These findings implicated that somatic mutations of BRCA2 genes may play a significant role in the pathogenesis of breast carcinoma in Taiwan. In addition, those events were associated with some early clinicopathological features.
Collapse
Affiliation(s)
- Fang-Ming Chen
- Department of Surgery, Kaohsiung Municipal Hsiao-Kang Hospital, 482 Shan-Ming Road Kaohsiung 812, Taiwan, ROC
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Kwiatkowska E, Teresiak M, Breborowicz D, Mackiewicz A. Somatic mutations in the BRCA2 gene and high frequency of allelic loss of BRCA2 in sporadic male breast cancer. Int J Cancer 2002; 98:943-5. [PMID: 11948477 DOI: 10.1002/ijc.10289] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Breast cancer occurs rarely in men and risk factors for the disease include germline mutations of the BRCA2 gene. High frequency of allelic loss at the BRCA2 locus has been reported in sporadic breast tumors, but somatic mutations of BRCA2 are very rare. Here we report the first case of somatic BRCA2 mutation in male breast cancer with demonstrated loss of heterozygosity. We analyzed a series of 27 archival samples from male breast cancer patients for BRCA2 mutations and loss of heterozygosity at BRCA2 locus. The mutation analysis of BRCA2 gene was performed using SSCA-HA and sequencing methods. PCR was used to detect LOH at 3 highly polymorphic microsatellite markers spanning BRCA2 region on 13q by comparing the allelic pattern in matched tumor and blood DNA samples. In this study LOH at the BRCA2 locus was observed in 82.6% of informative cases, confirming previous observations on high frequency of LOH affecting the BRCA2 region in male breast cancer. We identified 5 somatic BRCA2 mutations in a set of 23 sporadic male breast cancers (21%). Two silent and 1 missense alterations were novel BRCA2 variants. Here we also report first somatic frameshift BRCA2 mutation in male breast cancer 8138del5. In 3 tumors with somatic BRCA2 alterations, 1 missense, 1 silent and frameshift LOH at chromosome 13q12-13 were detected and losses involved a wild-type allele of BRCA2 gene.
Collapse
Affiliation(s)
- Eliza Kwiatkowska
- Department of Cancer Immunology, University School of Medical Sciences and Great Poland Cancer Center, Poznan, Poland
| | | | | | | |
Collapse
|
15
|
Watanabe Y, Nakajima H, Nozaki K, Ueda H, Obata K, Hoshiai H, Noda K. Clinicopathologic and immunohistochemical features and microsatellite status of endometrial cancer of the uterine isthmus. Int J Gynecol Pathol 2001; 20:368-73. [PMID: 11603221 DOI: 10.1097/00004347-200110000-00009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To clarify the clinicopathologic, molecular, and immunohistochemical characteristics of uterine isthmic endometrial cancer (UIE), we examined 13 cases of UIE and compared them with 33 cases of endometrial cancer of the uterine corpus (UCE) with respect to clinicopathologic factors, the expression of p53, the estrogen receptor (ER) and the progesterone receptor (PR) status, DNA ploidy, and microsatellite instability (MSI). Five (38.4%) of the UIE patients had stage I, two (15.4%) had stage II, and six (46.2%) had stage III disease (FIGO 1988). Myometrial invasion was confirmed in 92.3% of the UIE patients, and these patients had a higher (p < 0.05) frequency of > 50% myometrial invasion (46.2%) than the patients with UCE (15.2%). Moreover, the UIE patients had a higher frequency of positive peritoneal cytology (p < 0.05) and pelvic lymph node metastases (p < 0.05). No UIE tumors exhibited MSI, and the tumors in these patients had a higher expression of p53 (p < 0.01), a lower expression of ER (p < 0.05) and PR (p < 0.05), and a higher frequency of DNA aneuploidy (p < 0.01) than the UCE tumors. These findings suggest that the UIE is clearly different from UCE in the clinicopathologic, immunohistochemical features, and microsatellite status.
Collapse
Affiliation(s)
- Y Watanabe
- Department of Obstetrics and Gynecology, Kinki University School of Medicine, 377-2 Ohno-Higashi, Osakasayama, Osaka 589-8511 Japan.
| | | | | | | | | | | | | |
Collapse
|
16
|
de Leeuw WJ, van Puijenbroek M, Merx R, Wijnen JT, Bröcker-Vriends AH, Tops C, Vasen H, Cornelisse CJ, Morreau H. Bias in detection of instability of the (C)8 mononucleotide repeat of MSH6 in tumours from HNPCC patients. Oncogene 2001; 20:6241-4. [PMID: 11593433 DOI: 10.1038/sj.onc.1204795] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2001] [Revised: 06/05/2001] [Accepted: 07/05/2001] [Indexed: 11/09/2022]
Abstract
Recently, we and others reported instability in the (C)8 repeat in exon 5 of MSH6 as a preferential target for somatic mutations in tumours from MSH6 germline mutation carriers. Here, we report that in 45% of tumours from MLH1, MSH2 and MSH6 germline mutation carriers no sequence change in the (C)8 repeat of MSH6 was found upon DNA sequencing analysis of PCR products with a shift in electrophoresis mobility. Using "standard" PCR primers a high frequency of instability (50-86%) of the (C)8 repeat was found, but using a modified PCR reverse primer, accomplishing modulation of non-templated addition of adenine during in vitro PCR amplification by the Taq polymerase, a markedly lower frequency of instability was found in tumours from MLH1, MSH2 and MSH6 mutation carriers (6, 13 and 40%, respectively). Furthermore, a significant difference of the frequency of instability of the (C)8 repeat in tumours from MSH6 mutation carriers was found compared to MLH1, MSH2 mutation carriers. These results might have important implications for the detection of instability of other short mononucleotide repeats, e.g. TGFbetaRII, BAX, IGFRII, PTEN, BRCA2.
Collapse
Affiliation(s)
- W J de Leeuw
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Matias-Guiu X, Catasus L, Bussaglia E, Lagarda H, Garcia A, Pons C, Muñoz J, Argüelles R, Machin P, Prat J. Molecular pathology of endometrial hyperplasia and carcinoma. Hum Pathol 2001; 32:569-77. [PMID: 11431710 DOI: 10.1053/hupa.2001.25929] [Citation(s) in RCA: 232] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Four different genetic abnormalities may occur in endometrioid adenocarcinomas of the endometrium (mircosatellite instability and mutations in the PTEN, k-RAS and beta-catenin genes), whereas nonendometrioid carcinomas of the endometrium often have p53 mutations and loss of heterozygosity on several chromosomes. Occasionally, a nonendometrioid carcinoma may develop as a result of dedifferentiation of a preexisting endometrioid carcinoma; in such a case, the tumor exhibits overlapping clinical, morphologic, immunohistochemical, and molecular features of the 2 types. The insaturation of microsatellite instability in endometrial carcinogenesis seems to occur late in the transition from complex hyperplasia to carcinoma, and it is preceded by progressive inactivation of MLH-1 by promoter hypermethylation. Moreover, the endometrioid adenocarcinomas that exhibit microsatellite instability show a stepwise progressive accumulation of secondary mutations in oncogenes and tumor suppressor genes that contain short-tandem repeats in their coding sequences. Mutations in the PTEN and k-RAS genes are also frequent in endometrioid adenocarcinomas of the endometrium, particularly in the tumors that exhibit microsatellite instability, whereas beta-catenin mutations do not seem to be associated with such a phenomenon.
Collapse
Affiliation(s)
- X Matias-Guiu
- Department of Pathology, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Barcelona, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Koul A, Loman N, Malander S, Borg A, Ridderheim M. Two BRCA1-positive epithelial ovarian tumors with metastases to the central nervous system: a case report. Gynecol Oncol 2001; 80:399-402. [PMID: 11263939 DOI: 10.1006/gyno.2000.6085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cerebral metastasis secondary to ovarian cancer is a rare phenomenon. While no clear relationship to known prognostic factors is found, others suggest this as a biologically diverse behavior of ovarian cancer. CASES In a pilot study, 37 invasive epithelial ovarian cancer samples were analyzed to detect the frequency of BRCA1/BRCA2 mutations in the south of Sweden (results published). A retrospective follow-up revealed that 2 of these (2/37; 5.4%) patients developed central nervous system metastases during the course of their disease. Both patients had advanced surgical stage disease at the time of diagnosis, with histopathological serous type tumors that were negative for estrogen and progesterone receptors. One of these patients carried a germline BRCA1 mutation, whereas a somatic BRCA1 mutation was identified in the other patient. CONCLUSIONS To the best of our knowledge the molecular genetic profile of these tumors is not found in the literature and it is suggested that such analyses could provide some insight for a better understanding of this rare phenomenon.
Collapse
Affiliation(s)
- A Koul
- Department of Oncology and Gynecological Oncology, University Hospital, Lund, S-221 85, Sweden
| | | | | | | | | |
Collapse
|
19
|
Liu J, Yuan Y, Huan J, Shen Z. Inhibition of breast and brain cancer cell growth by BCCIPalpha, an evolutionarily conserved nuclear protein that interacts with BRCA2. Oncogene 2001; 20:336-45. [PMID: 11313963 DOI: 10.1038/sj.onc.1204098] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2000] [Revised: 11/08/2000] [Accepted: 11/09/2000] [Indexed: 11/08/2022]
Abstract
BRCA2 is a tumor suppressor gene involved in mammary tumorigenesis. Although important functions have been assigned to a few conserved domains of BRCA2, little is known about the longest internal conserved domain encoded by exons 14-24. We identified a novel protein, designated BCCIPalpha, that interacts with part of the internal conserved region of human BRCA2. Human BCCIP represents a family of proteins that are evolutionarily conserved, and contain three distinct domains: an N-terminus acidic domain (NAD) of 30-60 amino acids, an internal conserved domain (ICD) of 180-220 amino acids, and a C-terminus variable domain (CVD) of 30-60 amino acids. The N-terminal half of the human BCCIP ICD shares moderate homology with regions of calmodulin and M-calpain, suggesting that BCCIP may also bind Ca. Human cells express both a longer, BCCIPalpha, and a shorter, BCCIPbeta, form of the protein, which differ in their CVD. BCCIP is a nuclear protein highly expressed in testis. Although BCCIPbeta expression is relatively consistent in cancer cells, the expression of BCCIPalpha varies in cancer cell lines. The BCCIPalpha gene is located at chromosome 10q25.3-26.2, a region frequently altered in brain and other cancers. Furthermore, expression of BCCIPalpha inhibits breast and brain cancer cell growth, but fails to inhibit HT1080 cells and a non-transformed human skin fibroblast. These results suggest that BCCIPalpha is an important cofactor for BRCA2 in tumor suppression.
Collapse
Affiliation(s)
- J Liu
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center; 915 Camino de Salud, NE. Albuquerque, New Mexico, NM 87131, USA
| | | | | | | |
Collapse
|
20
|
Koul A, Malander S, Loman N, Pejovic T, Heim S, Willen R, Johannsson O, Olsson H, Ridderheim M, Borg Å Å. BRCA1 and BRCA2 mutations in ovarian cancer: Covariation with specific cytogenetic features. Int J Gynecol Cancer 2000; 10:289-295. [PMID: 11240689 DOI: 10.1046/j.1525-1438.2000.010004289.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed 37 primary invasive carcinomas for BRCA1 and BRCA2 mutations by screening the entire coding regions of both genes. Seven predicted truncating mutations (four in BRCA1 and three in BRCA2) and one novel BRCA1 missense variant (S1542C) were identified (8/37, 22%). Two of the BRCA1 mutations were somatic changes, whereas the remaining three BRCA1 changes and all mutations of BRCA2 were found to be of germline origin. All eight BRCA-positive tumors were serous or seropapillary carcinomas (8/27 serous tumors, 30%), and all but one were poorly differentiated. The correlation between tumor karyotype and BRCA status showed that clonal chromosomal aberrations were present in all BRCA-positive tumors (8/8) compared with 20 of 29 BRCA-negative ones. The most consistently affected region in BRCA-positive tumors was the long arm of chromosome 6; alterations within this arm with a breakpoint in band 6q21 were seen in four of five BRCA1-positive and in two of three BRCA2-positive tumors, but only in four of 20 karyotypically abnormal tumors without BRCA mutations, suggesting that the genetic pathways of tumor progression differ in the two groups. The high frequency of germline BRCA mutations detected in this pilot study (16% of 37 invasive carcinomas) points to the need for more extended analyses of population-based series of patients to determine the true contribution of these predisposing genes to the overall incidence of ovarian cancer in this population.
Collapse
Affiliation(s)
- A. Koul
- Departments of Oncology, Gynecological Oncology and Pathology, University Hospital, S-221 85, Lund, Sweden;Yale Hospital of New Haven, Connecticut; and Department of Genetics, The Norwegian Radium Hospital and Institute for Cancer Research, Oslo, Norway
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Santarosa M, Viel A, Boiocchi M. Splice variant lacking the transactivation domain of the BRCA2 gene and mutations in the splice acceptor site of intron 2. Genes Chromosomes Cancer 1999; 26:381-2. [PMID: 10534775 DOI: 10.1002/(sici)1098-2264(199912)26:4<381::aid-gcc14>3.0.co;2-n] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|