Prognostic Indicator of Melanoma Survival

The study was presented at the annual meeting of the United States and Canadian Academy of Pathology in Vancouver (Canada).

The study's goal was to evaluate the new CISH method developed by TriPath Oncology, a subsidiary of TriPath Imaging, Inc. (Burlington, NC, USA; www.tripathimaging.com), for determining melastatin expression in primary and metastatic melanoma and to correlate these findings with clinical outcomes. Melastatin is a melanocyte-specific gene discovered by Millennium Pharmaceuticals, Inc. (Cambridge, MA, USA), and has been identified as a potential prognostic biomarker of clinical outcome in patients suffering from cutaneous melanoma, which accounts for almost 75% of all skin cancer deaths.

In the study, melastatin mRNA was detected by CISH on formalin fixed paraffin embedded tissue sections from 56 primary melanoma patients with localized disease (stage I and II) and eight malignant melanoma patients (stage III/IV). The status of melastatin expression measured by using the CISH assay was correlated with known clinical outcome in these specimens. The study showed that in both primary and metastatic melanoma, loss of melastatin was associated with reduced patient survival and was an independent prognostic factor for overall patient survival. The five-year overall survival for complete melastatin expression was 34%; for partial loss, 50%; and for intact melastatin expression, 95%. On multivariate analysis, loss of melastatin expression and Clark's level (tumor thickness) were independent prognostic factors.

"Our study results are very encouraging and indicate that melastatin determination by CISH has the potential to supplement current, standard prognostic assessment of primary cutaneous melanomas in routine clinical practice,” said study director Jeffrey S. Ross, M.D., professor and chairman, department of pathology and laboratory medicine, Albany Medical College (New York, USA). "In this small cohort, CISH analysis of melastatin expression reproduces past radiometric in-situ hybridization findings highlighting that down-regulation of melastatin mRNA in primary melanoma is a prognostic biomarker for overall survival that is independent of other histologic biomarkers.”




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