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R K Schmutzler

Publications and source records attributed to R K Schmutzler.

At least 19 recordsLinked to original sources
PubMed2000

Breast MR imaging screening in 192 women proved or suspected to be carriers of a breast cancer susceptibility gene: preliminary results.

PURPOSE: To compare magnetic resonance (MR) imaging with conventional imaging in screening high-risk women. MATERIALS AND METHODS: This prospective trial included 192 asymptomatic and six symptomatic women who, on the basis of personal or family history or genetic analysis, were suspected or proved to carry a breast cancer susceptibility gene. RESULTS: Fifteen breast cancers were identified: nine in the 192 asymptomatic women (six in the first and three in the second screening round) and six in the symptomatic patients. Concerning the asymptomatic women, four of the nine breast cancers were detected and correctly classified with mammography and ultrasonography (US) combined; another two cancers were visible as well-circumscribed masses and were diagnosed as fibroadenomas. MR imaging allowed the correct classification and local staging of all nine cancers. In 105 asymptomatic women with validation of the 1st-year screening results, the sensitivities of mammography, US, and MR imaging were 33%, 33% (mammography and US combined, 44%), and 100%, respectively; the positive predictive values were 30%, 12%, and 64%, respectively. CONCLUSION: The accuracy of MR imaging is significantly higher than that of conventional imaging in screening high-risk women. Difficulties can be caused by an atypical manifestation of hereditary breast cancers at both conventional and MR imaging and by contrast material enhancement associated with hormonal stimulation.

Adult↗
PubMed1999

Exclusion of a major role for the PTEN tumour-suppressor gene in breast carcinomas.

PTEN is a novel tumour-suppressor gene located on chromosomal band 10q23.3. This region displays frequent loss of heterozygosity (LOH) in a variety of human neoplasms including breast carcinomas. The detection of PTEN mutations in Cowden disease and in breast carcinoma cell lines suggests that PTEN may be involved in mammary carcinogenesis. We here report a mutational analysis of tumour specimens from 103 primary breast carcinomas and constitutive DNA from 25 breast cancer families. The entire coding region of PTEN was screened by single-strand conformation polymorphism (SSCP) analysis and direct sequencing using intron-based primers. No germline mutations could be identified in the breast cancer families and only one sporadic carcinoma carried a PTEN mutation at one allele. In addition, all sporadic tumours were analysed for homozygous deletions by differential polymerase chain reaction (PCR) and for allelic loss using the microsatellite markers D10S215, D10S564 and D10S573. No homozygous deletions were detected and only 10 out of 94 informative tumours showed allelic loss in the PTEN region. These results suggest that PTEN does not play a major role in breast cancer formation.

BRCA2 Protein↗
PubMed1999

Messenger RNA determination of estrogen receptor, progesterone receptor, pS2, and plasminogen activator inhibitor-1 by competitive reverse transcription-polymerase chain reaction in human breast cancer.

Estrogen receptor (ER), progesterone receptor (PR), the estrogen-inducible protein pS2, and plasminogen activator inhibitor-1 (PAI-1) are important prognostic factors in primary breast cancer. The protein concentrations of these factors in breast tumors have been well documented. However, few data about the mRNA expression of ER, PR, pS2, and PAI-1 in breast cancer are available, which is mostly due to the limitations of conventional techniques for mRNA analysis. We have described a competitive reverse transcription-PCR system for the simultaneous quantification of ER, PR, pS2, and PAI-1 mRNA in tumor samples. Here, we evaluated 100 tumor biopsies from breast cancer patients for the mRNA expression of ER, PR, pS2, and PAI-1. The results were analyzed for correlations with protein status and with clinical data. Significant correlations between mRNA expression levels and protein concentrations of all tested markers were found. In only a few cases was there an obvious discordance between the measurable amounts of mRNA and protein, especially for ER and PR. In addition, ER, PR, and pS2 mRNA levels correlated significantly with each other. No correlation between PAI-1 mRNA amount and the expression of the other markers was found. With respect to clinical data, ER and PR mRNA levels were found to be inversely correlated to tumor size and histological grade but not to the lymph node status. pS2 and PAI-1 mRNA expression were not correlated with tumor size, grade, or lymph node involvement. In conclusion, competitive reverse transcription-PCR may be used as an alternative for the study of prognostic factors in human breast cancer and other malignancies. However, before mRNA expression is measured for diagnostics, a presumed concordance of mRNA and protein expression must be evaluated very carefully for every gene.

Adult↗
PubMed1998

Expression of the ATM gene is significantly reduced in sporadic breast carcinomas.

The gene mutated in ataxia telangiectasia (A-T) patients (ATM) is located on chromosome 11q22-23, a region frequently altered in mammary tumors. Patients homozygous for ATM mutations are prone to develop a variety of different neoplasms. Female heterozygotes have been reported to carry a 5- to 8-fold increased risk of breast cancer. However, germline mutations in the ATM gene are rare in women with sporadic breast carcinomas. Most of the alterations described in A-T patients result in a functionally inactive ATM protein. Moreover, it has been suggested that mutations of the ATM gene in A-T patients influence the amount of ATM mRNA and that this may affect the severity of the disease. In the present study, we have analyzed ATM transcripts in a series of 39 breast carcinomas, 14 benign breast lesions and 12 normal breast tissue samples. ATM mRNA levels were determined by semiquantitative competitive RT-PCR. Competitor RNA molecules for the ATM gene and the housekeeping gene beta-2-microglobulin (B2M) were generated by PCR mutagenesis. Low concentrations of ATM transcripts were detected in breast carcinomas, intermediate levels in benign lesions and highest levels in normal breast tissue specimens (F-test, p = 0.0013). Our results indicate that reduced expression of the ATM gene may contribute to the development and/or malignant progression of breast carcinomas.

Ataxia Telangiectasia Mutated Proteins↗
PubMed1997

Genomic deletions in the BRCA1, BRCA2 and TP53 regions associate with low expression of the estrogen receptor in sporadic breast carcinoma.

Sporadic breast carcinoma is associated with multiple genetic alterations. The clinical relevance of these alterations, however, needs further clarification. In the present study we analyzed 266 spontaneously arising breast carcinomas for allelic losses in the BRCA1 and TP53 regions on chromosome 17, the BRCA2 region on chromosome 13, the ATM (mutated in ataxia-telangiectasia) region on chromosome 11 and on the chromosomal arms 7q and 16q. In addition the following clinical and pathological parameters were evaluated: age at diagnosis, tumor size, presence or absence of regional and distant metastases, hormone-receptor status, histopathological classification and tumor grading. The analysis of genetic and clinical observations revealed significant associations: absence of expression of the estrogen receptor was linked to a high rate of allelic losses of markers in the BRCA1, TP53 and BRCA2 regions. Expression of the progesterone receptor coincided with allelic loss on the long arm of chromosome 16. High-grade malignant lesions and ductal differentiation were frequently associated with allelic losses in the proximal portion of chromosome 17q. The accumulation of multiple allelic deletions was linked to high-grade malignant tumors, to tumor size, and to loss of expression of the estrogen receptor. Our data point to a relationship between clinically relevant prognostic factors and specific genomic deletions in the BRCA1, BRCA2 and TP53 region.

Breast Neoplasms↗
PubMed1997

An optimized protocol for mRNA quantification using nested competitive RT-PCR.

Nested competitive reverse transcription polymerase chain reaction is an effective tool for the quantification of low level expressed mRNAs. Competitive RNA standards with small deletions allow the use cRT-PCR. The sensitivity is further increased by the utilization of nested PCR protocols. To optimize quantification of low abundance mRNAs we modified established protocols for use of automated labstations and semiautomated sequencers. In placental tissue, known for a very high CYP19 (P450AROM, aromatase) expression, cRT-PCR and nested cRT-PCR yielded virtually identical results which could be confirmed by Northern blotting. CYP19 mRNA in breast tumour tissue ranged below detection levels for Northern blotting; however, using our modified assay CYP19 showed 1.5 to 15 fold higher expression levels than in normal glandular breast tissue. Our approach proved to be useful for the quantification of a gene with low level expression. The employment of labstations and semiautomated sequencers allows rapid analysis of large sample numbers.

Aromatase↗
PubMed1996

Association of allelic losses on human chromosomal arms 11Q and 16Q in sporadic breast cancer.

Breast-carcinoma development presumably results from multiple mutational events in tumor-associated genes. Certain results indicate that some tumor-suppressor genes may combine their pathogenetic potential to synergistically promote tumor growth. In an effort to identify such mechanisms in breast tumors, a series of 77 (group I) paired blood tumor samples from patients with sporadic mammary carcinomas was analyzed for loss of heterozygosity with 15 polymorphic markers on the chromosomal arms 7q, 11q, 13q, 16q, 17p and 17q. A significant association was observed for the combination of allelic losses on chromosomes 11q and 16q. In order to confirm these findings, we studied a second independent series of 189 breast-tumor patients (group 2) with comparable histopathological tumor stages. Group 2 was examined for the same genetic alterations using the identical set of polymorphic markers. The data from this group confirmed the detected association of loss of heterozygosity on chromosomes 11q and 16q and indicate the cooperation of putative tumor-suppressor genes on the chromosomal arms 11q and 16q in a sub-set of breast carcinomas. The regions involved harbor the candidate genes ATM (mutated in ataxiatelangiectasia) on chromosome 11q23 and UVO (uvomorulin, cadherin E) and BBCI (breast basic conserved I) on chromosome 16q22-q24.

Alleles↗
PubMed1996

Evidence for a novel tumor suppressor gene on chromosome 15 associated with progression to a metastatic stage in breast cancer.

Loss of heterozygosity (LOH) studies have emerged as a valuable indicator for tumor suppressor genes involved in the formation or progression of carcinomas. We here present data indicating that human chromosome 15 harbours a novel putative tumor suppressor gene which appears to play a role during later stages of carcinogenesis and which may be associated with metastasis in breast cancer. In this study, 153 primary and metastatic carcinomas from 101 patients have been analysed for LOH with 13 polymorphic microsatellite markers on chromosome 15. The tumors included carcinoma of the lung in 49 patients, breast carcinoma in 29, colorectal carcinoma in nine, renal carcinoma in five, pancreatic carcinoma in five, urinary bladder carcinoma in two and prostate carcinoma and ovarial carcinoma in one patient each. LOH15 was seen in 42/99 (42%) informative patients. In metastatic tumors, LOH15 was observed in 37/68 (54%). High incidences of allelic losses were detected in metastases from lung (56%), breast (70%) and colorectal (67%) carcinomas. In carcinomas of the breast, there was a significant difference (P<0.01) in LOH15 frequencies between non-metastatic tumors (11%) and brain metastases (70%). Such a difference was not observed on the chromosomal arm 17p which yielded high proportions of LOH in both non metastatic breast tumor (73%) and breast carcinoma metastases (90%). In 16 patients, interstitial deletions could be detected. The common region of overlap extended from D15S231 to D15S641, thus mapping this putative tumor suppressor gene to chromosome 15q14. Our data indicate that a gene on chromosome 15 contributes to the pathogenesis of metastatic carcinoma.

Brain Neoplasms↗
PubMed1995

[Value of the Clearplan Ovulation Test in sterility treatment].

Detection of ovulation is an essential step in sterility treatment. Determination of the luteinising hormone is the most reliable method, which is generally performed by serum analysis. In this study, we proved the reliability of LH analysis in urine. 44 cycles of 35 volunteers with regular ovulatory cycles were examined. From day 11 on, daily LH measurements were performed on serum and urine. Ovulation was established by ultrasound monitoring of follicular development and/or by progesterone detection in the luteal phase. The sensitivity was 89% for serum analysis and 97.5% for urine analysis. The specificity was 100% for both methods. Hence, LH detection in urine is a reliable and secure method for ovulation determination. As an advantage over serum analysis, it requires less consultations, thereby offering a less expensive and stress reduced treatment.

Adult↗
PubMed1995

[Detection of genetic alterations in sporadic breast tumors].

OBJECTIVE: Loss of heterozygosity (LOH) indicates the existence of tumor suppressor genes (TSG) in the affected chromosomal loci. In order to uncover the involvement of such genes, we analyzed LOH in different chromosomal regions of sporadic breast carcinomas. MATERIAL AND METHOD: 47 breast cancer patients were screened for LOH with microsatellite markers on 18 different loci. DNA fragments were amplified by PCR from tumor and reference tissue. The PCR products were run on 8% denaturing polyacrylamide gels and visualized by silver straining. RESULTS: The following LOH-rates were found for the different loci: D6S497 (6p21, WAF-Region): 0%, D7S495: 9%, D7S522: 13%, D7S523: 22%, D11S488 (11q24-25): 38%, D13s321 and D13s765 (13q13-14, Rb-Region): 30% and 17%, D13S260 and D13S267 (13q12.3, BRCA2-Region): 28% both, D16S539 (16q22-24, E-Cadherin-Region): 35%, D17S5 (17p13.3): 17%, TP53 (17p13.1): 32% D17S250 (17q11-12): 22%, D17S855 (17q21 within the BRCA1 gene): 25%, D17S579 (17q21 telomer from BRCA1): 13%, D17S846 (centromere from BRCA1): 17%, 17q24 (SSTR 2): 9%, D22S684 (22q12, NF2-Region): 20%. Overall 66% of the tumors exhibited LOH. Lymphnode positive tumors showed significantly higher LOH rates than lymphnode negative tumors. CONCLUSIONS: Highest LOH-rates were found on chromosomes 11, 13, 16 and 17 indicative of relevant TSG's in the examined loci. In addition the findings indicate prognostic relevance of multiple LOH's in breast cancer.

Alleles↗
PubMed1994

[GnRH agonist treatment for in vitro fertilization in hyperandrogenemia].

Luteinising hormone (LH) is essential for steroidogenesis and folliculogenesis. In hyperandrogenic patients, however, an increased androgen production with the consecutive development of polycystic ovaries is caused by elevated LH levels. Suppression of androgens by the use of a GnRH agonist (a) may be a causal therapeutic approach. Therefore, we initiated a study comparing the combined GnRHa/HMG stimulation with HMG alone in hyperandrogenic patients undergoing in-vitro fertilisation (IVF). Altogether, 62 cycles were treated. Group 1 (n = 33) received a single depot injection of 3.6 mg goserelin on cycle day 22 followed by individualised HMG stimulation 14 days later. Group 2 (n = 29) started with the HMG stimulation on cycle day 3. In group 1, a pregnancy rate per transfer of 36.4% was achieved compared to only 20% in group 2. There was a strikingly lower abortion rate in group 1 that resulted in a significantly higher on going pregnancy rate. The results are in favour of the combined GnRHa/HMG stimulation as a first line therapy for hyperandrogenic IVF patients.

Adult↗
PubMed1993

An estrogen receptor genetic polymorphism and a history of spontaneous abortion--correlation in women with estrogen receptor positive breast cancer but not in women with estrogen receptor negative breast cancer or in women without cancer.

We previously identified a polymorphism in the human estrogen receptor gene. In a preliminary study on women with estrogen receptor positive (ER+) breast tumors, we found that the presence of the rarer of the two alleles, the B' allele, is correlated with a history of spontaneous abortion. Because that study evaluated only women with estrogen receptor positive (ER+) breast cancer, it was unknown whether the observed correlation was restricted to the cancer group or was independent of breast cancer. We have now extended our analysis to include not only additional women with ER+ breast cancer, but also those with estrogen receptor negative (ER-) breast cancer and women without cancer. Results of the current study continue to show an association between the B' allele and a history of spontaneous abortion in the ER+ breast cancer group. There was no such correlation either in the ER- breast cancer group or in the group without cancer. Also, we continue to observe, in the ER+ breast cancer group, a significantly higher concentration of ER protein in tumors from homozygous wild type women (genotype BB), than in the tumors from women who are heterozygous for the rarer allele (genotype BB'). We conclude that the combination of spontaneous abortion and the BB' ER genotype may be a marker for breast cancer susceptibility.

Abortion, Spontaneous↗
PubMed1992

Genetic research in embryology.

Based on findings on the molecular mechanisms of differentiation in drosophila, developmental genes have been identified in mammals similar to those in drosophila. Moreover, sequence similarities between drosophila developmental genes and mammalian growth factors provide evidence for common ancestors of such genes and suggest a complex link between growth and differentiation. As numerous oncogenes display their action as growth factors and are expressed during embryogenesis, differentiation and oncogenesis seem to be two sides of the same coin. Therefore, the aim of molecular embryology is twofold; elucidating differentiation processes and disclosing oncogenesis by studying the physiological function of oncogenes during development. Recent progress in molecular genetic technology now allows gene function to be studied by modification or disruption of genes. Models of clinical diseases have already evolved from such work and it is anticipated that progress in molecular embryology will further stimulate work on the diagnosis and therapy of genetic diseases as well as clinical oncology.

Animals↗
PubMed1991

Incidence of an estrogen receptor polymorphism in breast cancer patients.

We previously identified a polymorphism in the human estrogen receptor (ER) gene, within the coding region for the protein's amino terminal B-domain. In estrogen receptor-positive (ER+) breast tumors, the variant allele was preferentially associated with lower levels of ER, and was clinically correlated with frequent spontaneous abortions. DNA sequencing revealed a point mutation that changes codon 86 from Ala to Val and a silent mutation in codon 87. Because we initially detected the variant allele by analyzing RNA, only those tissues in which the ER gene is actively expressed were suitable for genotype analysis. We now describe an assay that uses genomic DNA as the substrate for determining the ER B genotype, DNA containing the polymorphic region of the ER gene is amplified by the polymerase chain reaction, then the amplified DNA is hybridized with radiolabeled oligonucleotide probes complementary to the wild type and variant ER alleles. This method allowed us to determine the ER B genotype of women with ER+ and ER- tumors, starting with minute amounts of DNA from frozen or paraffin embedded tissues. ER B genotyping was also performed on women without breast cancer using DNA extracted from blood cells. The combined results from analyses of RNA and DNA from 300 breast cancer patients showed that 12% were heterozygotes. In the ER+ group (n = 183), 11.5% carried the variant gene compared to 12.8% in the ER-negative group (n = 117) (chi 2 = 0.11; df = 1; p greater than 0.25).(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1990

Basic and clinical aspects of GnRH-agonists in reproduction.

Within recent years GnRH agonists have gained increasing importance in the treatment of reproductive failure. Their use as a pretreatment for in vitro fertilization increases the pregnancy rate at least under certain conditions. In cases of endometriosis and uterus myomatosus, GnRH agonists achieve high remission rates and may avoid or at least postpone the need for surgical intervention. The physiological basis and current clinical strategies are discussed.

Endometriosis↗
PubMed1989

Differences in membrane properties between unfertilised and fertilised single rabbit oocytes demonstrated by electro-rotation. Comparison with cells from early embryos.

The apparent membrane capacity of tubular rabbit oocytes increases from 1.7-2.0 microF/cm2 before fertilisation to 3.7-4.0 microF/cm2 after fertilisation. The membrane conductivity measured on single cells was also increased by fertilisation from less than 1 mS/cm2 to 14 mS/cm2. Cells obtained from 2-, 4- or 8-cell embryos exhibited intermediate values of membrane capacity (2.3-2.8 microF/cm2) and conductivity (5-22 mS/cm2). The values quoted are those effective between 1 and 10 kHz, the frequency of the rotating field used. The large apparent capacities are probably due to the presence of structures such as microvilli which cause the actual membrane area to exceed the smooth sphere area. It must be assumed that these structures change in form or number on fertilisation, and that they persist in embryos, at least up to the 8-cell stage. No difference was apparent between cells fertilised in vitro or in vivo. Comparison of the above zona-free data with measurements on zona-complete oocytes indicate how fertilised and unfertilised rabbit eggs may be distinguished from one another, even in the presence of the zona pellucida.

Animals↗