摘要:

Ultraviolet-B (UV-B) triggers a cascade of events involving cell cycle control genes leading ultimately to DNA repair or apoptosis. The hypothesis examined here is that the genetic abnormality predisposing to melanoma affects the ability of the cell to respond appropriately to UV-B, so favouring mutagenesis. Epstein-Barr virus-transformed lymphoblastoid cell lines from hereditary melanoma kindreds were irradiated with UV-B, and changes in p53, p21 and Bcl-2 expression and cell cycle phase distribution were analysed. Twenty-two cell lines were tested: 12 carriers of melanoma susceptibility and 10 non-carriers (unaffected first degree relatives). At 24 h after irradiation with 50 J/m2, 15 of the 22 cell lines showed a rise in G2/M. After 400 J/m2, all the cell lines showed a reduction or loss of G2/M and 17 of the 22 showed an S phase delay. More carriers than non-carriers of melanoma susceptibility showed significant S phase delay after 50 J/m2(seven out of 12 carriers versus two out of 10 non-carriers). Six of the 10 pairs (carrier versus non-carrier) tested showed discordant cell cycle responses; however the nature of the difference was not universal. Bcl-2 reduction was seen 4 h post-irradiation in all the carriers and non-carriers. The p53 and p21 responses, although showing some individual variations, were not related to carrier status. These results show individual variations in response to UV-B irradiation among cell lines from the members of hereditary melanoma kindreds, but no consistent differences between carriers and non-carriers of melanoma susceptibility.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The regulation of apoptosis is believed to be dependent on the balance of the activities of different intracellular signalling systems. Activation of the SAPK/JNK pathway is implied in pro-apoptotic signalling, while activation of the MEK1/ERK pathway may have a viability-promoting effect. We show here that treatment with the MEK1 inhibitor PD98059 sensitizes the human melanoma cell line C8161 to cisplatin-induced apoptosis. In these cells, cisplatin at 40 μM did not elicit significant cell death, whereas massive cell death was seen when cells were pretreated for 20 h with 40 μM PD98059 before the addition of cisplatin. Concomitant addition of PD98059 and cisplatin did not have any sensitizing effect, and PD98059 on its own did not induce apoptosis. However, in three other human melanoma cell lines PD98059 did not potentiate cisplatin-induced apoptosis. Instead, in one of these cell lines (AA), PD98059 protected against cisplatin-induced cytotoxicity. We conclude that blocking of the MEK1/ERK pathway may, in some instances, potentiate the cytotoxic effect of cisplatin on human melanoma cell lines, whereas in other instances it may have a protective effect. Thus it cannot be regarded as a general approach to sensitizing melanoma cells to drug-induced apoptosis.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The mouse melanoma cell lines B16, K1735 and Cloudman S91-M3 (and various sublines) are frequently used as melanoma models. Extensive comparative data of their immunological features are not available. In order to define the immunological profiles of these cell lines, relevant tumour markers were studied. S91-M3 melanoma cells constitutively expressed high levels of major histocompatibility complex (MHC) I, in contrast to K1735-M2 and B16-F1 cells. MHC II expression was restricted to B16-F1 cells following interferon-γ treatment. Tyrosinase, tyrosinase-related protein-2 and gp100 were detected in B16-F1 and S91-M3 cells, but not in K1735-M2 cells. Constitutive surface expression and secretion of intercellular adhesion molecule-1 was found on S91-M3 cells. No substantial secretion of interleukin-10 could be detected. In contrast, low levels of latent transforming growth factor-β were found in the cell supernatants of B16-F1 and K1735-M2 cells. The expression pattern of Fas, FasL and FLICE inhibitory protein was comparable in all three cell lines. Thus our findings indicate that each cell line presents a characteristic immunological profile, confirming that B16-F1 is an appropriate murine tumour model for tumours with low levels of MHC I but expressing melanoma-associated antigens. S91-M3 represents a complementary, more immunogenic model. In contrast, K1735-M2 does not seem to be an appropriate model for melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Automated melanoma diagnosis is a popular focus of research, with numerous papers describing techniques and results. In our study, we identified two possible problems with the current method of automated diagnosis, where systems are intended to reproduce histopathology results. We propose a new method of identifying problematic skin lesions, namely attempting to reproduce algorithmically the perceptions of dermatologists as to whether the lesion should be excised. In the best case, our initial model reproduced the decision of dermatologists in over 80% of cases. These results suggest that reproducing the decision to excise may be a valuable adjunct to current methodology.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Epiluminescence light microscopy (ELM) has proven useful in the diagnosis of pigmented skin lesions (PSLs). However, in some cases this technique does not sufficiently increase the diagnostic accuracy in distinguishing pigmented Spitz naevi (PSNs) from melanoma. With the aim of obviating these problems of qualitative interpretation, methods based on the mathematical analysis of PSLs, such as digital dermoscopy analysis (DDA), have recently been developed. In the present study we used a digital dermoscope (DBDermo-MIPS, Dell'Eva-Burroni) to analyse PSNs and melanomas with similar clinical and dermoscopic features for any correlation between variables and to determine its discriminating power with respect to histological diagnosis. The 100 lesions underwent histological examination by three experienced dermatopathologists and were identified as PSNs (43) or melanomas (57). Thirty-six parameters were identified as possible discriminating variables and were grouped in four categories: geometry, colour, texture, and islands of colour. Statistical analysis was used to identify the variables with the highest discriminating power. Stepwise discriminant analysis selected only four variables: entropy, minimum diameter, red lesion value and peripheral dark (the means of these variables were higher in melanomas than in PSNs). Thus the combined use of digital dermoscopy and stepwise logistic discriminant analysis made it possible to single out the best objective variables for distinguishing PSN and melanoma.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Sentinel lymph node biopsy was attempted in 336 patients with clinically node-negative cutaneous melanoma. All patients were injected with technetium-99m labelled radio-colloid, with 108 patients simultaneously receiving vital blue dye for sentinel node identification. Sentinel lymph nodes were identified in 329 patients, giving a technical success rate of 97.9%. Metastatic disease was identified in 39 (11.9%) of the patients in whom sentinel nodes were found. Patients with negative sentinel nodes were observed and patients with positive sentinel nodes underwent comprehensive lymph node dissection. The presence of metastatic disease in the sentinel nodes and primary tumour depth by Breslow or Clark levels were joint predictors of survival based on Cox proportional hazards modelling. Disease recurrences occurred in 26 (8.8%) patients with negative sentinel lymph nodes, with isolated regional recurrences as the first site in 10 (3.4%). No patients with Clark level II primary tumours were found to have positive sentinel nodes or disease recurrences. One patient with a thin (< 0.75 mm) Clark level III primary had metastatic disease in a sentinel node. Patients with metastases confined to the sentinel nodes had similar survival rates regardless of the number of nodes involved

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Various histopathological techniques have been developed in order to improve the detection of micrometastasis in the regional lymph nodes of patients with malignant melanoma. Our standard histopathological examination of lymph nodes included haematoxylin and eosin (H & E) staining and immunohistochemistry (IH) using antibodies to HMB-45 and S-100 proteins of three paraffin sections at one level. In addition, lymph nodes were examined by molecular biological methods using tyrosinase reverse transcription-polymerase chain reaction (RT-PCR). In this study, we investigated the use of step sections and IH in lymph nodes regarded as negative by standard histopathology but positive by tyrosinase RT-PCR, suggesting the presence of tumour cells. In a series of 76 consecutive patients with stage I and II cutaneous melanoma, a total of 156 regional lymph nodes were examined by H & E staining, IH and tyrosinase RT-PCR. All lymph nodes were bisected along their long axis for separate evaluation. In 21 patients, at least one lymph node in the regional nodal basin reported as tumour-negative by standard histopathology was demonstrated to express tyrosinase (total number of nodes = 33). These 33 lymph nodes were re-examined by H & E and IH at 10 additional levels of the paraffin block. Only one lymph node from one patient had occult melanoma cells in deeper levels detected exclusively by IH. Six out of 20 patients with positive findings exclusively on tyrosinase RT-PCR developed tumour recurrences during a median follow-up of 34 months. We therefore conclude that additional step sectioning with IH does not significantly increase the detection of tumour-positive lymph nodes. Patients with melanoma cells detected exclusively by RT-PCR, however, were shown to be at increased risk for tumour recurrence.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The aim of this study was to develop a highly sensitive two-marker assay for the detection of circulating melanoma cells in patients’ blood using a reverse transcriptase-polymerase chain reaction (RT-PCR). We analysed the usefulness of two different sets of markers: tyrosinase and MUC-18 (TYR/MUC-18), and tyrosinase and MART 1 (TYR/MART 1). Total cellular RNA was isolated from 337 blood samples from 80 melanoma patients at different stages of the disease. All patients had undergone primary surgery. Assay sensitivity and specificity were confirmed using three different melanoma cell lines and two different fibroblast lines. In addition, blood from 47 healthy subjects and 10 patients with non-melanoma cancer was used as a negative control. We found that two-marker analysis is more accurate than the single tyrosinase assay. The frequency of melanoma cell detection in patients’ blood was about 10% higher when the TYR/MART 1 two-marker assay was used. Using this assay we did not find any statistical correlation between the molecular markers and the UICC stage of disease or the Breslow thickness or Clark level of the primary melanoma. The frequency of melanoma cell detection with the TYR/MUC-18 two-marker assay was even higher than the TYR/MART 1 assay, but unfortunately the MUC-18 transcript was also present in about 20% of healthy subjects. Therefore we do not recommend the use of MUC-18 as a standard value marker.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

It is currently unclear whether any combination therapy for the treatment of metastatic melanoma is superior to standard single-agent dacarbazine (DTIC) in terms of tumour response and overall survival. The available randomized clinical trial data were combined in a meta-analysis to address this question. Initially a thorough MEDLARS search was conducted covering the time period from January 1970 to January 1999. This literature search was supplemented by manual searches of study bibliographies (including review articles) and review of relevant textbooks. The meta-analysis was performed according to a prospective protocol using strict study eligibility criteria. Data derived from randomized controlled trials comparing single-agent DTIC with combination chemo/immunotherapy were combined using a fixed effects model. Data were stratified into three combination therapy groups: DTIC-containing regimens, non-DTIC-containing therapy, and chemotherapy plus immunotherapy. The primary outcome of interest was the proportion of patients demonstrating a complete or partial response to treatment. A total of 20 randomized trials comprising 3273 patients were initially combined in a meta-analysis. This yielded an odds ratio (OR) of 1.23 (95% confidence interval [CI] 1.02–1.48), demonstrating that combination drug therapies are associated with a 23% increase in response rate compared with single-agent DTIC. The combination of DTIC plus interferon-α produced a tumour response rate 53% greater (95% CI 1.10–2.13) than that seen with DTIC alone. This increase was greater than that seen with DTIC-containing multi-drug regimens, which had an OR of 1.33 (95% CI 0.99–1.78). No difference in overall survival was demonstrated. Non-DTIC-containing treatment programmes showed no advantage over DTIC in terms of tumour response rate (OR = 0.77, 95% CI 0.45–1.32). The combination of DTIC and interferon-α appears more active than standard single-agent DTIC in metastatic melanoma. Further randomized clinical trials employing a DTIC plus interferon arm are necessary to confirm these results.

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0960-8931    

出版商:OVID    

年代:2001

数据来源: OVID