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Biomedical subjects

H G Schnürch

Publications and source records attributed to H G Schnürch.

At least 19 recordsLinked to original sources
PubMed2004

[Vulvar carcinoma. Diagnosis and therapy].

Vulvar cancer is a rare entity. It appears mostly in older women aged 70-79 years with a slow tendency to younger age. More than 90% of the tumors show a squamous differentiation. The correspondent preneoplasia is VIN 3. This lesion occurs in women mostly younger than 35 years. Experts assume vulvar cancer to appear in two different types:HPV-induced type in younger women and non-HPV-dependent type in older women. The preneoplasia VIN 3 already should be treated by resection or destruction. Invasive carcinomas stage I or II can be treated by wide local excision. The inguinofemoral lymph nodes should be resected if invasion exceeds 1 mm in depth. In larger primary tumors, vulvectomy with bilateral inguinofemoral node dissection is indicated. In advanced tumor stages, multimodal concepts are applied: primary radiotherapy or radiochemotherapy may precede a salvage operation.

Aged↗
PubMed1999

[Reconstructive surgery of the efferent urinary tract in pelvic exenteration of gynecological tumors].

In locally advanced or recurrent tumors of the female genital tract anterior or total exenteration may be mandatory in case of tumor invasion into the lower urinary tract or if a second course of radiation therapy is not feasible. The management of resection and reconstruction of the affected lower urinary tract has to be well integrated into the gynecological therapeutic concept. In 11/32 patients the reconstruction of the partially resected lower urinary tract was feasible with preservation of a functionally intact urinary bladder. Urinary diversion following pelvic exenteration was achieved in 13/17 patients with a continent urinary reservoir and in 4/17 patients with an ileal conduit. Operative reinterventions were needed only in patients with continent urinary diversion in 5 cases. All these patients had a past history of primary radiation therapy of their gynecological tumor. In the remaining other 11 patients with a history of primary radiation therapy no complications occurred. 9 of 32 patients survived the operative procedure 40.8 (25-57) month with no evidence of recurrent tumor. Continent urinary diversion represents an excellent therapeutic option for replacement of function lost due to exenterative pelvic surgery. Stringent selection of patients is mandatory to consider the presented therapeutic concept a reasonable tool in the management of the described clinical situations.

Adult↗
PubMed1998

[Relative indicators for disease outcome in breast carcinoma].

Tumor size, axillary nodal status, histologic grading and the hormonal receptor status are the established prognostic factors for breast carcinoma. Concurrent to these factors the clinical validation of the new innovative tumor characteristics from molecular biology is difficult to achieve. Clinicians are more and more interested in indicators of response to particular treatments (predictive factors) and less in prognostic factors relevant for the natural course. The hormonal receptor status is the best known predictive factor with regard to the response to hormonal treatment. Among the innovative parameters the tumor suppressor gene p53 and the oncogene Her2/neu show a good correlation to sensitivity to cytostatic treatment. The detection of more and more molecular mechanisms of tumor growth and tumor spread raise hopes that innovative treatment approaches will lead to an antineoplastic effect. The molecular tumor parameters then may play the role of predictive factors for a specific treatment. For the present the established tumor factors should be used as the base for a treatment plan and the available already known predictive factors should be taken into consideration.

Biomarkers, Tumor↗
PubMed1998

[Tumor risk consultation for predisposed women from high risk cancer families].

Germline mutations of the cancer susceptibility genes BRCA1 and BRCA2 seem to lead to a very high risk for breast and/or ovarian cancer. Therefore, genetic counselling and identification of high-risk families may be essential to offer the opportunity to participate in a specific early cancer detection program and to provide individualized psychological support. In a two year period (August 1994-August 1997) 304 consultees present for genetic counselling at the interdisciplinary cancer genetic clinic (Department of Obstetrics & Gynecology and Human Genetics, Heinrich-Heine-Universität, Düsseldorf). For genetic testing a BRCA1/2 mutation detection strategy including protein truncation test (PTT), single strand conformation polymorphism (SSCP), and direct DNA sequencing is used. 161 families fulfilled the inclusion criteria; at present, 72 families for whom complete analytical material is available are analyzed. Although genetic testing for BRCA1 and BRCA2 is technically challenging, women with a family history of multiple sporadic breast/ovarian cancers and those with a hereditary BRCA1 and BRCA2 gene defect may be distinguished. For the first group of consultees this may ease their concern, for the second group preventive measures including an early cancer detection or prevention program, psychological support or prophylactic surgery may be discussed.

BRCA1 Protein↗
PubMed1998

[Pelvic exenteration from the surgical viewpoint].

Pelvic exenteration (PE) is associated with specific problems in the indication of excision and reconstructive surgery. Indication are colorectal cancer or cervical cancer recurrence. In each case intensive and early cooperation of gynecologist, surgeon and urologist is warranted. Thus, PE is indicated in some T3 N1 and T4 rectal carcinoma patients without distant metastases and may be superior to chemotherapy. In cervix carcinoma recurrence, PE with or without intestinal reconstruction is of specific importance. While intestinal reconstruction may improve the quality of life in R0 resected patients we reluctantly perform this in noncurative treated patients, since their expected survival time is limited and reconstructive surgery in these pretreated patients (radiation and surgery) increases the risk of morbidity.

Adult↗
PubMed1997

Multistep carcinogenesis of breast cancer and tumour heterogeneity.

Breast cancer emerges by a multistep process which can be broadly equated to transformation of normal cells via the steps of hyperplasia, premalignant change and in situ carcinoma. The elucidation of molecular interdependencies, which lead to development of primary breast cancer, its progression, and its formation of metastases is the main focus for new strategies targetted at prevention and treatment. Cytogenetic and molecular genetic analysis of breast cancer samples demonstrates that tumour development involves the accumulation of various genetic alterations including amplification of oncogenes and mutation or loss of tumour suppressor genes. Amplification of certain oncogenes with concomitant overexpression of the oncoprotein seems to be specific for certain histological types. Loss of normal tumour suppressor protein function can occur through sequential gene mutation events (somatic alteration) or through a single mutational event of a remaining normal copy, when a germline mutation is present. The second event is usually chromosome loss, mitotic recombination, or partial chromosome deletion. Chromosome loci 16q and 17p harbour tumour suppressor genes, which seem to be pathognomonic for the development or progression of a specific histological subtype. There are an overwhelming number of abnormalities that have been identified at the molecular level which fit the model of multistep carcinogenesis of breast cancer. When the functions of all of these genes are known and how they participate in malignant progression, we will have the tools for a more rational approach to diagnosis, prevention and treatment. This review deals only with the factors that are involved in the conversion of a normal breast cell into a malignant cell rather than those required for invasion and metastases. A key critical long-term step in the molecular analysis of breast cancer will be to link the specific molecular damage with the effects of environmental carcinogens.

Breast Neoplasms↗
PubMed1996

Clinical impact of detection of loss of heterozygosity of BRCA1 and BRCA2 markers in sporadic breast cancer.

The development of familial and sporadic breast cancer is based on genetic alterations of tumour-suppressor genes, for which loss of heterozygosity (LOH) is one mechanism of gene inactivation. To investigate LOH of BRCA1 (17q21) and BRCA2 (13-q12-13) in sporadic breast cancer, polymerase chain reaction (PCR)-based fluorescent DNA technology for detection of microsatellite polymorphisms was applied. A total of 137 breast cancer and 15 benign breast specimens with matched normal tissue were examined. Fluorescent-labelled PCR products were analysed in an automated DNA sequencer (ALFTM Pharmacia). Losses at both loci were correlated with different histological types, age, tumour size, lymph node status, grading and steroid hormone receptor expression, [SHR: oestrogen receptor (ER), progesterone receptor (PgR)]. For BRCA1 (D17S855, THRA1, D17S579) losses could be detected in invasive ductal carcinoma (IDC; n = 108) in 32-38%, invasive lobular carcinoma (ILC; n = 19) in 21-42% depending on the marker applied, but not in benign breast tumours (n = 15). Losses of BRCA1 markers correlated with larger tumour size, higher grade, and PgR expression. For BRCA2 (D13S260, D13S267, D13S171) losses could be detected in 108 IDCs in 30-38%, in 19 ILCs in 17-39% depending on the marker applied, but not in benign breast tumours. Losses of BRCA2 markers correlated only with higher grade. Microsatellite analyses combined with detection of fluorescent-labelled PCR products by an automated laser DNA sequencer can be used for routine determination of LOH. In sporadic breast cancer, LOH of BRCA1 of BRCA2 does not add decisive prognostic value as stated for familial breast cancer.

Age Factors↗
PubMed1996

[Therapy of preinvasive vulvar neoplasia--standardized or individual?].

The mostly diagnosed preinvasive vulvar neoplasia is of squamous origin called "vulvar intraepithelial neoplasia" (VIN). The knowledge about the biological character of these lesions especially grade 3 is limited. Progression to invasive cancer is expected in > 40 % of untreated patients who are mostly immunocompromised or elderly. After surgical treatment of VIN the risk of invasive cancer is about 4 %. There are no significant differences in later progression and relapse rates between different surgical approaches. Risk factors for relapse are: younger age, positive margins, grade 3, multicentricity, associated intraepithelial neoplasias of the vagina and uterine cervix and immunosuppression. The aim of treatment is the removal of all lesions with negative margins. Individually adapted surgical excision is mandatory to conserve the function and figure of the vulva. Standard surgical procedures are wide local excision or laser vaporisation after safe histological characterisation.

Adult↗
PubMed1996

Early cancer detection programmes for women at high risk for breast and ovarian cancer: a proposal of practical guidelines.

Women from families with multiple breast and/or ovarian cancers may be at increased risk to develop breast/ovarian cancer themselves. Due to personal experience with family members having these diseases they are anxious and ask for specific prophylactic measurements or treatment. The detection of two susceptibility genes, BRCA1 and BRCA2, has given insight into the genetic background of part of the familial breast/ovarian cancer syndromes. This has led to an increased demand in genetic counselling, testing, and early cancer detection programmes. Prospective data from early cancer detection programmes in this high risk population are yet not available. Based on data from epidemiological risk studies, breast and ovarian screening programmes and follow up data from breast cancer trials recommendations for an early cancer detection programme have been summarized. At the present these recommendations are tested in a prospective trial.

Adult↗
PubMed1996

Detection of sequential genetic alterations relevant for breast cancer development.

Breast cancer emerges as a multistep process with transformation of normal cells via steps of hyperplasia, premalignant change and in situ carcinoma. Cytogenetic and molecular genetic analyses of breast cancer samples indicate that tumour development involves the accumulation of various genetic alterations, including amplification of oncogenes and mutation or loss of tumour suppressor genes. Microdissection of histological sections is needed to correlate the specific histological change and the genetic alteration. For detection of oncogene amplification quantitative differential polymerase chain reaction (PCR) can be used. For assessment of loss of heterozygosity PCR-based microsatellite polymorphisms detecting differences in short tandem repeat sequences are much more informative than standard two-allele restriction fragment length polymorphism markers. Still, the direct correlation of the genetic alterations to specific histological findings is the key to reveal insight into tumour biology and thereby gain prognostic information for the individual breast cancer patient.

Breast Neoplasms↗
PubMed1995

ERBB2 gene amplification detected by fluorescent differential polymerase chain reaction in paraffin-embedded breast carcinoma tissues.

For quantificative determination of ERBB2 gene amplification in archival human carcinoma specimens we have developed a rapid, non-radioactive approach, which is based on the differential polymerase chain reaction (PCR) and fluorescent DNA technique. Sequences from the ERBB2 gene and from a single-copy reference gene were amplified simultaneously by PCR, in which one of each primer pair was fluorescently labelled. PCR products were separated by polyacrylamide gel electrophoresis in an automated DNA sequencer and directly quantified after laser activation and emission scanning using appropriate software. This fluorescent differential polymerase chain reaction (fd-PCR) method was used for quantificative determination of ERBB2 gene amplification in 195 formalin-fixed, paraffin-embedded breast carcinoma tissues. ERBB2 gene amplification was found in 52 (26%) of these tumors and correlated significantly with tumor size, absence of estrogen receptor (ER) and pS2 expression, but not with absence of progesterone receptor (PR) or presence of epidermal growth factor receptor (EGF-R) expression, lymph-node metastases or grading. In univariate analysis, ERBB2 gene amplification showed no significant correlation with clinical outcome, either in the whole population or in the subgroup defined by positive axillary lymph-node metastases. However, within the node-negative subgroup, patients with ERBB2 gene amplification had significantly decreased relapse-free survival and overall survival (p < 0.05). The fd-PCR assay is a valuable tool for determination of amplification of ERBB2 gene as well as further oncogenes. In this way, more detailed information about individual tumor biology may be acquired by a routine assay.

Analysis of Variance↗
PubMed1995

[Immunohistochemical detection of epidermal growth factor receptor (EGF-R) in paraffin sections of breast carcinoma tissue: correlation and clinical significance].

Analyses of the level of expression of the epidermal growth factor receptor (EGF-R) of breast cancer tumours may add independent information about the prognosis for individual patients. Furthermore, the use of monoclonal antibodies directed against EGF-R as therapeutic tools (e.g., Mab 425) requires a reliable evaluation of the individual EGF-R content. Various analytical methods have been published, including (1) biochemical detectonn of EGF-R by a radiolabelled physiological ligand, (125I)EGF, (2) enzymatic analyses of EGF-R content (IEMA), (3) immunological analyses of EGF-R content with a monoclonal antibody (ELISA), and (4) immunohistochemical EGF-R detection. Studies with immunohistochemical analyses of EGF-R overexpression in formalin-fixed, paraffin-embedded tumour samples are rare. In a retrospective study, we examined the clinical data from 142 patients and the EGF-R expression in their formalin-fixed, paraffin-embedded tumour samples. The average follow-up was 69 months. EGF-R expression was compared to oestrogen (ER) and progesterone (PgR) receptor expression, histological grade, tumour size, lymph node metastases and menopause. 52 of 142 tumours were EGF-R positive. EGF-R overexpression correlated with high tumour grade, large tumours and elevated numbers of lymph node metastases. There was no significant correlation between ER or PgR and EGF-R expression. Determination of EGF-R overexpression revealed no significant difference in disease-free interval (DFI) or overall survival (OS). In this study, the determination of EGF-R in formalin-fixed, paraffin-embedded tumour samples proved feasible. Unfortunately, this did not add any additional information concerning DFI or OS.

Adult↗
PubMed1994

Growth inhibition of xenotransplanted human carcinomas by a monoclonal antibody directed against the epidermal growth factor receptor.

In the athymic nude mice model with xenotransplanted human carcinomas, the effect of a monoclonal antibody (MAb 425), directed against the human epidermal growth factor (EGFR), on tumour growth was studied. Five different solid human breast carcinomas and one vulvar epidermoid cancer cell line (A431) were transplanted in nude mice, and treated with MAb 425 2.2 mg intraperitoneally (i.p.) on day 7 post-transplantation. Tumours with EGFR concentrations of > or = 16 fmol/mg soluble cytosolic protein showed growth inhibition, whereas the growth pattern of EGFR-negative tumours was unaffected. Variation of MAb 425 dosage (1.1 versus 2.2 mg) revealed no difference in the growth inhibiting effect. Different application schedules (application on day 0, 12 or 26) showed different onsets and durations of tumour growth inhibition. Repeated application (1.1 mg, day 0 and 12) was followed by a prolonged inhibitory effect. Our results suggest that growth inhibition of EGFR-positive tumours by MAb 425 may lead to an additional treatment option for patients with EGFR-positive cancer.

Animals↗
PubMed1993

[The erbB gene family: significance for tumor development, prognosis and new therapeutic modalities].

RNA and DNA viruses can be transforming and tumourigenic agents. The transformation is a consequence of the ability of viruses to integrate into the host cell's DNA and to produce transforming proteins. These proteins are mainly produced by specific integral parts of the viral genome, the oncogenes. Comparison between RNA/DNA sequence of viral oncogenes and normal human genome of non-transformed cells revealed high sequence similarities in specific genomic areas, which were named cellular proto-oncogens. They are important components of the growth regulatory pathways in normal cells. The accumulation of genetic alterations of some proto-oncogens, like the erbB-family, may be part of the mechanism, by which malignant cells can acquire a selective growth advantage. The epidermal growth factor receptor (EGF-R, c-erbB1), Her-2/neu (c-erbB2), and c-erbB3 are members of the erbB-family. The detection of increased abundance of EGF-R or Her-2/neu proteins in human tumours can provide additional information on the disease-free survival and overall survival for patients with breast, ovarian, endometrial or cervical cancer. Molecular and cell-physiological analyses have improved the understanding of tumour biology and provide the opportunity for new therapeutic approaches. Monoclonal antibody targeted therapy directed against EGF-R or Her-2/neu, the use of anti-sense oligonucleotides and oligodeoxynucleotides, and the application of tyrosine kinase and protein C-kinase inhibitors are currently being investigated.

Cell Division↗