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P Kaskel

Publications and source records attributed to P Kaskel.

At least 19 recordsLinked to original sources
PubMed2001

Extra c-myc oncogene copies in high risk cutaneous malignant melanoma and melanoma metastases.

Amplification and overexpression of the c-myc gene have been associated with neoplastic transformation in a plethora of malignant tumours. We applied interphase fluorescence in situ hybridization (FISH) with a locus-specific probe for the c-myc gene (8q24) in combination with a corresponding chromosome 8 alpha-satellite probe to evaluate genetic alterations in 8 primary melanomas and 33 advanced melanomas and compared it to 12 melanocytic nevi, 7 safety margins and 2 cases of normal skin. Additionally, in metaphase spreads of 7 melanoma cell lines a whole chromosome 8 paint probe was used. We investigated the functionality of the c-myc gene by detecting c-myc RNA expression with RT-PCR and c-myc protein by immunohistochemistry. 4/8 primary melanomas and 11/33 melanoma metastases showed additional c-myc signals relative to the centromere of chromosome 8 copy number. None of the nevi, safety margins or normal skin samples demonstrated this gain. In 2/7 melanoma cell lines (C32 and WM 266-4) isochromosome 8q formation with a relative gain of c-myc copies and a loss of 8p was observed. The highest c-myc gene expression compared to GAPDH was found in melanoma metastases (17.5%). Nevi (6.6%) and primary melanomas (5.0%) expressed the c-myc gene on a lower level. 72.7% of the patients with c-myc extra copies had visceral melanoma metastases (UICC IV), patients without c-myc gain in 35.0% only. The collective with additional c-myc copies also expressed the gene on a significantly higher level. These results indicate that a c-myc gain in relation to the centromere 8 copy number might be associated with advanced cutaneous melanoma.

Adolescent↗
PubMed2001

Coexpression patterns of EGFR, HER2, HER3 and HER4 in non-melanoma skin cancer.

The receptor tyrosine kinases (RTKs) epidermal growth factor receptor (EGFR), HER2, HER3 and HER4 are involved in the pathogenesis of multiple human malignant neoplasias. However, their role in the carcinogenesis of basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) remains to be elucidated. In order to further define the role of these RTKs, 56 human skin tissue samples of normal skin, BCC and SCC were studied by conventional and differential and quantitative reverse transcriptase-polymerase chain reaction (rtPCR). EGFR and HER3 were predominantly expressed in the BCCs and SCCs, while HER2 was ubiquitously expressed. HER4 was not expressed in any sample. Since in vitro studies have provided compelling evidence that heterodimer formation of these receptors are associated with different signal transduction processes, coexpression patterns might be decisive for the induction and maintenance of a malignant phenotype. These results confirm this concept: isolated HER2 expression and EGFR/HER2 were predominantly found in normal skin, while HER2/HER3 and the triple expression of EGFR/HER2/HER3 were seen more frequently in the BCCs and SCCs compared with normal skin (50% and 40% compared with 26%, respectively). The activation of HER3, in addition to EGFR and HER2, might therefore be associated with the malignant phenotype. However, due to the small numbers in this study, further confirmation of the patterns is needed.

Biopsy↗
PubMed2001

Increased blood levels of human S100 in melanoma chick embryo xenografts' circulation.

The chorioallantoic membrane (CAM) of the fertilized egg allows grafting of human melanomas for short-term investigations and offers the opportunity to investigate the behavior of metastasizing cells and the release of S100beta into peripheral blood. Tissue from one primary melanoma as well as cutaneous and subcutaneous metastases of 10 melanoma patients with elevated levels of S100 in the peripheral blood before surgery were transplanted onto the CAM of chick embryos at day 5/6 of development. Grafts were nourished by the host blood supply 2 days after transplantation. Histologically, 3 days after grafting, metastasizing melanoma cells could be found near the vessels of the host membrane, penetrating the endothelial layer and entering the blood system. Growth conditions remained stable for 6 days after transplantation. Blood samples were taken from a larger CAM vessel before collecting the xenografts 5 days after grafting. Measurement of human S100 in peripheral blood was performed in a blinded manner. No negative control showed elevated levels of human S100 protein. Samples deriving from melanoma xenografts contained highly elevated levels of S100 protein in 80% of cases. The data strongly support the concept of graft-host interaction concerning adherence of tumors and extravasation of human melanoma cells.

Animals↗
PubMed2001

UVB-induced decrease of p16/CDKN2A expression in skin cancer patients.

The lack of p16 expression has been shown in cultured melanoma cells, however contradictory evidence for p16 expression in melanoma tissues exist. Ultraviolet (UV) C and UVB have been shown to affect p16 expression, which impairs cell cycle regulation in vitro and in vivo. In this study, p16/CDKN2A gene expression was determined by reverse transcription polymerase chain reaction in seven skin cancer patients, in one dysplastic nevus patient and in seven healthy individuals, prior to UVB exposure and at various times after application of one minimal erythema dose (MED). Five of the seven skin cancer patients showed a down-regulation of p16/CDKN2A expression after UVB exposure, while controls remained unaltered. The UVB-induced decline of p16/CDKN2A in skin cancer patients might offer new insights into photocarcinogenesis. The putative sequence of events could start with a down-regulation of p16/CDKN2A expression, which would lead to impaired cell cycle regulation. Altered expression patterns of p16/CDKN2A following UVB exposure could be of value for identifying people with an increased risk of UV-induced skin cancer.

Adolescent↗
PubMed2001

Outdoor activities in childhood: a protective factor for cutaneous melanoma? Results of a case-control study in 271 matched pairs.

BACKGROUND: A matched case-control study was performed in Munich, Germany, in 1996-97 to evaluate the risk of cutaneous melanoma due to ultraviolet (UV) exposure behaviour in Southern Bavaria, Germany. OBJECTIVES: Patients with cutaneous melanoma and controls were investigated by two physicians using a standardized questionnaire to identify risk factors for the development of melanoma, such as professional and leisure sun exposure behaviour. In each person, a total body examination was performed to detect benign skin alterations, phenotypic characteristics and precursor lesions for skin cancer. PATIENTS/METHODS: A total of 271 melanoma patients and 271 controls were individually matched for residence, age and gender. A multiple conditional logistic regression analysis was performed. RESULTS: Of 56 factors, those risk factors with a strong effect on the development of melanoma were: the existence of melanoma in first degree relatives, solar lentigo, actinic keratosis, actinic cheilitis, skin phototype, immediate skin reaction to UV light at the start of the outdoor season, sunburn in childhood and sun exposure during holidays in sunny areas 20 years before melanoma was diagnosed; outdoor activities in childhood were found to be protective. CONCLUSIONS: Sunburn in childhood and increased sun exposure during annual holidays in sunny areas should be avoided. In contrast, outdoor activities in childhood, including soccer and gardening, should be encouraged because they are associated with a lower risk of melanoma formation.

Adolescent↗
PubMed2000

Antiapoptotic bcl-2 and bcl-xL in advanced malignant melanoma.

Apoptosis is an important cofactor in the pathogenesis of a plethora of malignancies. However, little is known about modulation of the expression of bcl gene family in melanocytic tumors. To determine the role of bcl-2, bcl-x and bax in melanocytic tumors we investigated the differential expression of these genes via RT-PCR in tissue samples from human benign nevi, primary melanomas and melanoma metastases in comparison with normal skin. Bcl-2 was strongly expressed in 14/16 metastases (87.5%), whereas only 7/13 primary melanomas (53%), 7/15 nevi (46%) and 7/16 normal tissue samples (43%) showed expression of bcl-2 (P < 0.05). There was a strong indication of a correlation between tumor thickness and bcl-2 expression in nodular malignant melanomas. Expression of bcl-x was found in 16/16 melanoma metastases (100%), 11/13 primary melanomas (84%), 12/15 nevi (80%) and 10/16 normal tissue samples (62%) (P < 0.05). Bcl-xL expression increased from primary melanoma to melanoma metastases, whereas bcl-xS showed a decreasing expression level during melanoma progression. No differences in bax expression were seen between melanoma metastases, primary melanoma, nevi and normal tissue. Immunohistochemical investigations of another 53 tissue samples showed similar results. Our results strongly indicate that bcl-2 and bcl-xL gene expression increases with progression of malignant melanoma. Bcl-2 and bcl-xL expression could reflect an increased malignant potential caused by an inhibition of apoptosis and growth advantage for metastatic melanoma cells.

Apoptosis↗
PubMed2000

Lymph node dissection in cutaneous melanoma: surgical and oncological implications.

The concept of Sentinel Lymph Node Dissection (SLND) has strongly influenced the surgical approach towards primary melanoma in the last decade. Initiated by the disappointing results of elective lymph node dissection (ELND) in this malignancy, the concept of analyzing the first draining lymph node (Sentinel) of a regional basin was developed as a diagnostic means to avoid unnecessary ELND in case of negative SLNs. According to recent standards detection of the SLN should be performed by a triple approach: injection of 90 nm Technetium and patent blue in the periphery of the primary melanoma, and intraoperative tracing of radioactivity with the aid of a hand-held gamma probe. Histopathological examination of alternating series sections of the whole lymph node appears to be the best analytic approach. Molecular biologic procedures such as tyrosinase RT-PCR are time-consuming to perform and produce contradictory results. SLND for cutaneous melanoma is an interdisciplinary diagnostic approach involving surgery, dermatology, pathology, and nuclear medicine. In spite of a variety of published promising results derived from clinical trials ranging from a few dozens to several hundred included patients the diagnostic and prognostic value of SLND remains to be confirmed by ongoing controlled prospective clinical trials. At this stage, SLND can by no means be considered a therapeutic procedure. These aspects have to be kept in mind when informed consent is obtained from patients as well as in the individual determination of the risk-benefit ratio.

Clinical Trials as Topic↗
PubMed2000

Trauma and melanoma formation: a true association?

BACKGROUND: Little is known about the role of mechanical trauma in the pathogenesis of malignant melanoma. In individual patients, traumatic events have been discussed as a causative factor for the induction of melanoma and diagnosis of melanoma following trauma may raise medico-legal questions. OBJECTIVES: To evaluate the relationship between traumatic single or recurrent events and melanoma characteristics. METHODS: Retrospective questionnaire in 369 melanoma patients. RESULTS: A large number of patients (337 of 369; 91.3%) denied an association between a possible traumatic event and melanoma formation. Thirty-two of 369 patients (8.7%) considered an association of trauma and melanoma formation likely. Of these 32 patients, 22 patients (13 men, nine women) reported a single event, and 10 patients (four men, six women) a persisting irritation. An irritation of a pre-existing melanocytic naevus was reported by two patients with histologically confirmed melanoma on acquired or congenital naevus. CONCLUSIONS: As most of the patients who mentioned a trauma in this study suffered from acral melanoma, or melanoma located on the extremities, a history of trauma should be expected more frequently at these body sites. A review of epidemiological, clinical and scientific research indicates that there seems to be no evidence for single or persistent traumatic events as a causative factor for melanoma formation.

Adolescent↗
PubMed2000

Calcipotriol vs. tazarotene as combination therapy with narrowband ultraviolet B (311 nm): efficacy in patients with severe psoriasis.

BACKGROUND: Phototherapy has been shown to be one of the most effective treatment modalities for patients with psoriasis. Nevertheless, photocombination therapies capable both of reducing cumulative ultraviolet (UV) doses and of accelerating clearance of skin lesions are important and of high interest. There have been no published studies comparing the effect of narrowband UVB irradiation in combination with topical application of tazarotene vs. calcipotriol. OBJECTIVES: To determine, in a half-side manner, whether a combination of UVB (311 nm) and tazarotene is superior to UVB (311 nm) plus calcipotriol or vice versa. METHODS: Ten patients suffering from widespread symmetrical psoriasis were treated for at least 4 weeks with topical calcipotriol and tazarotene in a half-side distribution. Additionally, the whole body was irradiated with narrowband UVB (311 nm) four times a week. Before treatment and once weekly during therapy a modified Psoriasis Area and Severity Index was estimated for each body half. The total treatment time, number of treatment sessions and cumulative UVB dose necessary for clearance of skin lesions were determined in an observer-blind fashion for each patient. Furthermore, all patients completed a quality of life questionnaire. RESULTS: Clearance of psoriasis was observed after a median of 19 treatment sessions (range 14-28) and a median cumulative UVB dose of 22.98 J cm-2 (range 9.24-58.22) simultaneously for both body halves. On the side treated with topical tazarotene gel, four patients complained of itching and dryness of the skin, and skin irritation was observed in three of them. Six patients preferred the application of tazarotene gel, while four preferred calcipotriol. CONCLUSIONS: Our clinical comparison of narrowband UVB with either topical calcipotriol or topical tazarotene revealed no significant therapeutic difference between both regimens. Although these results need to be confirmed in larger patient groups, we feel that both photocombination therapies can broaden the therapeutic options for moderate to severe psoriasis vulgaris and may reduce the cumulative UVB dose during therapy.

Administration, Topical↗
PubMed2000

Treatment of chronic plaque-stage psoriasis and psoriatic arthritis with mycophenolate mofetil.

Mycophenolate mofetil (MMF), a widely used immunosuppressant in organ transplantation, is a recent addition to the therapeutic armamentarium of autoimmune and inflammatory skin disorders in dermatology. We describe 5 patients with moderate to severe chronic plaque psoriasis and 6 patients with psoriatic arthritis that was refractory to conventional systemic and/or topical antipsoriatic treatment who were treated with MMF monotherapy (2 g/d) in a 10-week study. Although MMF was tolerated well in all patients, only patients with moderate psoriasis and psoriatic arthritis improved with therapy, whereas patients with severe psoriasis did not respond to MMF. Although MMF seems to be effective and safe for blistering autoimmune diseases and pyoderma gangrenosum, our data do not allow optimistic statements on the use of MMF in severe plaque-stage psoriasis. However, MMF may develop into an interesting therapeutic alternative for patients with psoriatic arthritis.

Adult↗
PubMed2000

Comprehensive allelotype and genetic anaysis of 466 human nervous system tumors.

Brain tumors pose a particular challenge to molecular oncology. Many different tumor entities develop in the nervous system and some of them appear to follow distinct pathogenic routes. Molecular genetic alterations have increasingly been reported in nervous system neoplasms. However, a considerable number of affected genes remain to be identified. We present here a comprehensive allelotype analysis of 466 nervous system tumors based on loss of heterozygosity (LOH) studies with 129 microsatellite markers that span the genome. Specific alterations of the EGFR, CDK4, CDKN2A, TP53, DMBT1, NF2, and PTEN genes were analyzed in addition. Our data point to several novel genetic loci associated with brain tumor development, demonstrate relationships between molecular changes and histopathological features, and further expand the concept of molecular tumor variants in neuro-oncology. This catalogue may provide a valuable framework for future studies to delineate molecular pathways in many types of human central nervous system tumors.

Alleles↗