Prognostic Factors in Malignant Melanoma

S100A13 is a new angiogenic marker in human melanoma

Angiogenesis is critical in melanoma progression and metastasis and relies on the synthesis and release of proangiogenic molecules such as vascular endothelial growth factor (VEGF)-A and fibroblast growth factors (FGFs). S100A13 is a small calcium-binding protein that facilitates the release of FGF-1, the prototype of the FGF family. S100A13 is upregulated in astrocytic gliomas, in which it correlates with VEGF-A expression, microvessel density and tumor grading, and promotes a more aggressive, invasive phenotype in lung cancer-derived cell lines. To investigate the involvement of S100A13 in human cutaneous melanoma, we analyzed a series of 87 cutaneous melanocytic lesions: 14 common acquired melanocytic nevi, 14 atypical, so-called 'dysplastic' nevi, 45 melanomas (17 radial growth phase and 28 vertical growth phase) and 14 melanoma metastases. Main clinical and pathological features, including histotype, Breslow thickness, Clark's level and outcome were recorded. Microvessel density was determined with CD105/endoglin staining. Semiquantitative determination of S100A13, FGF-1 and VEGF-A protein expression was obtained by immunostaining. Quantification of S100A13 mRNA was achieved by real-time PCR. We found that S100A13 was expressed in melanocytic lesions; compared with benign nevi, S100A13 protein expression was significantly upregulated in melanomas (P=0.024), in which it correlated positively with the intensity of VEGF-A staining (P=0.041) and microvessel density (P=0.007). The level of expression of S100A13 mRNA also significantly increased with progression of disease, from radial growth phase (0.7+/-0.7) to vertical growth phase (3.6+/-3.1) to metastases (7.0+/-7.0) (P<0.001). Furthermore, S100A13 mRNA correlated positively with VEGF-A (P=0.023), TNM stage (P=0.05), risk of relapse (P=0.014) and status at follow-up (P=0.024). In conclusion, S100A13 is expressed in melanocytic lesions when the angiogenic switch occurs and it may cooperate with VEGF-A in supporting the formation of new blood vessels, favoring the shift from radial to vertical tumor growth. Therefore, S100A13 may represent a new angiogenic and prognostic marker in melanoma.

Low plasma coenzyme Q10 levels as an independent prognostic factor for melanoma progression

BACKGROUND

Abnormally low plasma levels of coenzyme Q10 (CoQ10) have been found in patients with cancer of the breast, lung, or pancreas.

OBJECTIVE

A prospective study of patients with melanoma was conducted to assess the usefulness of CoQ10 plasma levels in predicting the risk of metastasis and the duration of the metastasis-free interval.

METHODS

Between January 1997 and August 2004, plasma CoQ10 levels were measured with high-performance liquid chromatography in 117 consecutive melanoma patients without clinical or instrumental evidence of metastasis according to American Joint Committee on Cancer criteria and in 125 matched volunteers without clinically suspect pigmented lesions. Patients taking CoQ10 or cholesterol-lowering medications and those with a diagnosis of diabetes mellitus were excluded from the study. Multiple statistical methods were used to evaluate differences between patients and control subjects and between patients who did (32.5%) and did not (67.5%) develop metastases during follow-up.

RESULTS

CoQ10 levels were significantly lower in patients than in control subjects (t test: P < .0001) and in patients who developed metastases than in the metastasis-free subgroup (t test: P < .0001). Logistic regression analysis indicated that plasma CoQ10 levels were a significant predictor of metastasis (P = .0013). The odds ratio for metastatic disease in patients with CoQ10 levels that were less than 0.6 mg/L (the low-end value of the range measured in a normal population) was 7.9, and the metastasis-free interval was almost double in patients with CoQ10 levels 0.6 mg/L or higher (Kaplan-Meier analysis: P < .001).

LIMITATIONS

A study with a larger sample, which is currently being recruited, and a longer follow-up will doubtlessly increase the statistical power and enable survival statistics to be obtained.

CONCLUSIONS

Analysis of our findings suggests that baseline plasma CoQ10 levels are a powerful and independent prognostic factor that can be used to estimate the risk for melanoma progression.

High frequency of melanoma-associated antigen or HLA class I loss does not correlate with survival in primary melanoma

Melanoma-associated antigens are at the center of many immunotherapeutic trials in melanoma. Little is known about the impact of antigen expression on the natural course of disease. We stained 110 cases of primary melanoma with a median follow-up of 13 years (range 10-18 years) for melanoma-associated antigens gp100, MelanA/MART-1, MAGE-3, tyrosinase, and for HLA class I molecules. Of 91 cases evaluated, we found immunoreactivity for gp100, MelanA/MART-1, and tyrosinase in 88%, 80%, and 87% of primary tumors, respectively, for MAGE-3 in 37% and for HLA class I in 86% of primary tumors. Loss, that is, heterogeneous expression within primary tumors, was most pronounced for gp100 (73% of primary tumors) and least for MAGE-3 (27% of primary tumors). MelanA/MART-1 and tyrosinase expression loss was 58% and 59% of primary tumors, respectively. There was a high rate of expression loss for HLA class I (74%). Univariate and multivariate statistical analysis of expression in primary tumors and loss of melanoma antigens as well as HLA class I in individual primary tumors showed no significant correlation to overall survival. Loss of gp100 and loss of tyrosinase expression showed a negative survival trend over homogeneous expression of these antigens, although not reaching statistical significance (P = 0.08 and P = 0.09, respectively). We conclude that loss of melanoma antigen expression as well as HLA class I expression is a frequent observation in primary melanoma. However, no statistically significant correlation between loss of these antigens in individual primary tumors and negative impact on overall survival was found in our cohort.

Exposure of melanoma cells to dacarbazine results in enhanced tumor growth and metastasis in vivo

PURPOSE

In recent years, the incidence of cutaneous melanoma has increased more than that of any other cancer. Dacarbazine is considered the gold standard for treatment, having a response rate of 15% to 20%, but most responses are not sustained. Previously, we have shown that short exposure of primary cutaneous melanoma cells to dacarbazine resulted in the upregulation of interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF). The purpose of the present study was to determine how long-term exposure of melanoma cells to dacarbazine would affect their tumorigenic and metastatic potential in vivo.

MATERIALS AND METHODS

The primary cutaneous melanoma cell lines SB2 and MeWo were repeatedly exposed in vitro to increasing concentrations of dacarbazine, and dacarbazine-resistant cell lines SB2-D and MeWo-D were selected and examined for their ability to grow and metastasize in nude mice.

RESULTS

The dacarbazine-resistant cell lines SB2-D and MeWo-D exhibited increased tumor growth and metastatic behavior in vivo. This increase could be explained by the activation of RAF, MEK, and ERK, which led to the upregulation of IL-8 and VEGF. More IL-8, VEGF, matrix metalloproteinase-2 (MMP-2), and microvessel density (CD-31) were found in tumors produced by SB2-D and MeWo-D in vivo than in those produced by their parental counterparts. No mutations were observed in BRAF.

CONCLUSION

Our results have significant clinical implications. Treatment of melanoma patients with dacarbazine could select for a more aggressive melanoma phenotype. We propose that combination treatment with anti-VEGF/IL-8 or MEK inhibitors may potentiate the therapeutic effects of dacarbazine.

Tumor vascularity in the prognostic assessment of primary cutaneous melanoma

PURPOSE

The vascular supply of the primary tumor is recognized to play an important role in the progression of a number of solid tumors. However, the role of tumor vascularity in the prognostic assessment of melanoma remains unclear. The purpose of this study was to determine the prognostic impact of patterns of vascularity on the outcome associated with cutaneous melanoma.

PATIENTS AND METHODS

Tumor vascularity was documented prospectively using routine histopathologic analysis of 417 primary cutaneous melanomas from the University of California at San Francisco Melanoma Center database. Four patterns of tumor vascularity were recorded: absent, sparse, moderate, and prominent.

RESULTS

Increasing tumor vascularity significantly increased the risk of relapse and death associated with melanoma, corresponding to reduced relapse-free and overall survival. By multivariate analysis, tumor vascularity was the most important determinant of overall survival, surpassing tumor thickness. Increasing tumor vascularity was associated with increased incidence of ulceration in the primary tumor.

CONCLUSION

Tumor vascularity is an important prognostic factor in melanoma, rivaling tumor thickness. Increasing tumor vascularity is highly correlated with ulceration, possibly helping to explain the biologic basis of this known prognostic factor.

Melastatin expression and prognosis in cutaneous malignant melanoma

PURPOSE

Melastatin (MLSN-1), a novel melanocyte-specific gene recently identified using a genomic approach, is expressed in murine and human melanoma cells at levels inversely proportional to metastatic rates in vivo. We studied the relationship between expression of melastatin mRNA in the primary cutaneous tumor and prognosis in patients with localized malignant melanoma.

PATIENTS AND METHODS

Melastatin mRNA was evaluated by in situ hybridization in primary cutaneous melanoma from 150 patients with localized disease (American Joint Committee on Cancer [AJCC] stage I and II). Multivariate Cox proportional hazards regression analysis was performed to assess the prognostic utility of melastatin mRNA expression while adjusting for other prognostic indicators.

RESULTS

Uniform melastatin mRNA expression in the primary tumor was correlated with prolonged disease-free survival (P < .0001). Multivariate analysis revealed that melastatin status, mitotic rate, and tumor thickness influence disease-free survival independently. The 8-year disease-free survival rate in AJCC stage I patients whose tumors diffusely expressed melastatin mRNA was 100%, whereas in stage I patients with melastatin loss, the disease-free survival rate was 77% +/- 15% (median +/- SE). In patients with stage II disease whose tumors diffusely expressed melastatin mRNA, the 8-year disease-free survival rate was 90% +/- 7%, whereas in patients with melastatin loss, the disease-free survival rate was 51% +/- 8%.

CONCLUSION

Downregulation of melastatin mRNA in the primary cutaneous tumor is a prognostic marker for metastasis in patients with localized malignant melanoma and is independent of tumor thickness and other variables. Used in combination, melastatin status and tumor thickness allow for the identification of subgroups of patients at high and low risk of developing metastatic disease.