Transcription factors and other dysregulated proteins in melanoma prognosis.

Approximately one third of patients with cutaneous melanoma later develop a metastatic disease, having then an extremely poor rate of survival. Because of the highly unpredictable nature of melanomas, finding those patients who are likely to develop a metastatic disease and those patients who probably will survive is an ongoing challenge. The current "conventional" prognosticators, such as Breslow thickness, Clark level of invasion, and ulceration, cannot perfectly predict the clinical course of this disease at an individual level. Although the sentinel lymph node biopsy procedure and reverse transcription polymerase chain reaction techniques have significantly improved the staging of patients with melanoma, new molecular prognostic markers may help in selection of appropriate patients for strenuous adjuvant therapies and for randomized clinical trials. Furthermore, these markers also improve our basic understanding of the biology of cutaneous melanoma, potentially offering new targets for novel treatment strategies. This paper reviews the current literature on transcription factors and other dysregulated proteins involved in melanoma prognosis.

Reduced level of CD44 and hyaluronan associated with unfavorable prognosis in clinical stage I cutaneous melanoma.

The cell surface glycoprotein CD44 and its ligand, hyaluronan (HA), enhance growth and metastatic capacity of melanoma cells in vitro, but their clinical significance in primary cutaneous melanoma is still unclear. Therefore, we studied whether the levels of CD44 and HA associate with disease progression and survival of cutaneous melanoma. A series of 292 clinical stage I cutaneous melanomas was analyzed by immunohistochemistry using an anti-CD44H antibody (clone 2C5). HA was demonstrated histochemically using a biotinylated HA-specific affinity probe (bHABC). The reduced staining levels of CD44 and HA were associated with each other and indicators of progressive disease. Reduced CD44 and HA level, high tumor thickness, high pT category, high Clark's level, bleeding, and male gender predicted short univariate recurrence free survival (RFS) and overall survival (OS). In Cox's multivariate analysis (N: = 251), the decreased level of CD44, high tumor thickness, and bleeding predicted independently short RFS. High tumor thickness and bleeding were associated with short OS. We conclude that the reduced cell surface CD44 and HA levels associate with poor prognosis in clinical stage I cutaneous melanoma. The notion that the decreased level of CD44 independently predicts short RFS suggests that reduced cell surface CD44 enhances the spreading potential in localized cutaneous melanoma and that quantification of CD44 offers a prognostic tool for its clinical evaluation.

Failure in post-transcriptional processing is a possible inactivation mechanism of AP-2alpha in cutaneous melanoma.

The loss of transcription factor AP-2alpha expression has been shown to associate with tumourigenicity of melanoma cell lines and poor prognosis in primary cutaneous melanoma. Altogether these findings suggest that the gene encoding AP-2alpha (TFAP2A) acts as a tumour suppressor in melanoma. To learn more of AP-2alpha's down-regulation mechanisms, we compared the immunohistochemical AP-2alpha protein expression patterns with the corresponding mRNA expression detected by in situ hybridization in 52 primary melanomas. Of the 25 samples with AP-2alpha protein negative areas, 16 (64%) expressed mRNA throughout the consecutive section. Nine specimens (36%) contained equally mRNA- and protein-negative areas, suggesting that the loss of AP-2alpha protein associated with lack of the mRNA transcript. The highly AP-2alpha protein-positive tumours (n = 27) were concordantly mRNA positive in 25 (92.6%) cases. Thirteen primary tumours were further analysed using microsatellite markers D6S470 and D6S263 for loss of heterozygosity (LOH) of a locus harbouring TFAP2A. LOHs or chromosome 6 monosomy were found in four out of five (80%) informative AP-2alpha mRNA- and protein-negative tumour areas, but also within five out of 13 (38%) informative AP-2alpha mRNA-positive tumour areas. This chromosome region is thus suggestive of harbouring a putative tumour suppressor gene of cutaneous melanoma, but this referring specifically to TFAP2A could not be completely verified in this analysis. We conclude that a failure in post-transcriptional processing of AP-2alpha is a possible inactivation mechanism of AP-2alpha in cutaneous melanoma.

p21(WAF1/CIP1) expression in stage I cutaneous malignant melanoma: its relationship with p53, cell proliferation and survival.

The expression of p21, p53 and proliferating cell nuclear antigen (PCNA) was analysed by immunohistochemistry in a consecutive series of 369 clinical stage I cutaneous malignant melanoma patients. Correlation of the detected expression levels with each other, with clinicopathological data and with melanoma survival were statistically evaluated. p21 expression was significantly associated with p53 and PCNA expression levels. In addition, high levels of p53 and PCNA were significantly interrelated. Tumour thickness, recurrent disease, high TNM category and older (> or = 55 years) age at diagnosis were inversely associated with p21 expression. Gender, bleeding, tumour thickness, Clark's level of invasion, TNM category and p53 index were all important predictors of both recurrence-free and overall survival of melanoma. In Cox's multivariate analysis including 164 patients with a complete set of data, only high tumour thickness and bleeding predicted poor recurrence-free survival (P = 0.0042 and 0.0087 respectively) or overall survival (P = 0.0147 and 0.0033 respectively). Even though elevated p21 expression may be associated with more favourable prognosis in clinical stage I cutaneous melanoma, our results suggest that cell cycle regulatory effects of p21 can be overcome by some other and stronger, partly yet unknown, mechanisms.

Downregulation of transcription factor AP-2 predicts poor survival in stage I cutaneous malignant melanoma.

PURPOSE: The transcription factor, activator protein (AP)-2, a 52-kd DNA-binding protein, is suggested to inhibit tumor growth through the activation of p21. To test this hypothesis, we analyzed AP-2 and p21 protein expressions in stage I cutaneous malignant melanomas to clarify their significance with regard to tumor progression and survival. PATIENTS AND METHODS: A consecutive series of 369 clinical stage I cutaneous malignant melanoma patients were investigated using immunohistochemistry. The detected expression levels were correlated with each other, with clinicopathologic data, and with melanoma survival. RESULTS: The loss of AP-2 expression was significantly associated with low p21 expression (P=.007), high tumor thickness (P=.001), high Clark's level (P=.046), high tumor-node-metastasis (TNM) category (P=.006), recurrent disease (P=.001), and male sex (P=.03). Tumor thickness, Clark's level, TNM category, bleeding, AP-2 index, and sex were all important predictors of both recurrence-free survival (RFS) and overall survival (OS) of melanoma in this order. In Cox's multivariate analysis, high tumor thickness (P=.0001), low AP-2 index (P=.0153), and bleeding (P=.0143) predicted poor RFS. Poor OS was predicted by high tumor thickness (P=.0008) and bleeding (P=.0092). CONCLUSION: The loss of AP-2 expression seems to be associated with malignant transformation and tumor progression in cutaneous malignant melanoma. This tumor-suppressive action of AP-2 may be mediated through p21 regulation. Furthermore, decreased AP-2 expression is independently associated with elevated risk of subsequent metastatic behavior of stage I cutaneous malignant melanoma.

Mitotic rate and S-phase fraction as prognostic factors in stage I cutaneous malignant melanoma.

Clinical data from 369 patients with clinical stage I cutaneous malignant melanoma treated in Kuopio University Hospital district between 1974 and 1989 with a mean follow-up of 6.4 years were analysed. Clinical parameters, histology, DNA index, S-phase fraction (SPF) and mitotic indices [mitotic activity index (MAI) and volume-corrected mitotic index (M/V index)] were correlated with the outcome of the disease to establish their value as predictors of stage I cutaneous malignant melanoma. In univariate survival analyses, bleeding, gender, tumour thickness, level of invasion according to Clark, TNM category, MAI, M/V index and SPF were the most significant predictors of recurrence-free (RFS) and overall survival. In Cox's multivariate analysis, tumour thickness (P = 0.0021), bleeding (P = 0.0106) and M/V index (P = 0.0058) predicted poor RFS in the 259 patients available for the analysis. Poor overall survival was predicted by MAI (P = 0.0002), bleeding (P = 0.004), SPF (P = 0.009) and male gender (P = 0.034). The present results indicate that mitotic activity index (MAI), volume-corrected mitotic index (M/V index) and S-phase fraction (SPF) are important prognostic factors in addition to the well-established Breslow thickness in stage I cutaneous malignant melanoma.