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Gene Expression Profiling-Based Identification of Molecular Subtypes in Stage IV Melanomas with Different Clinical Outcome.

Author:
  • Göran B Jönsson
  • Christian Busch
  • Stian Knappskog
  • Jürgen Geisler
  • Hrvoje Miletic
  • Markus Ringnér
  • Johan R Lillehaug
  • Åke Borg
  • Per Eystein Lonning
Publishing year: 2010
Language: English
Pages: 3356-3367
Publication/Series: Clinical Cancer Research
Volume: 16
Issue: 13
Document type: Journal article
Publisher: American Association for Cancer Research

Abstract english

PURPOSE: The incidence of malignant melanoma is increasing worldwide in fair-skinned populations. Melanomas respond poorly to systemic therapy, and metastatic melanomas inevitably become fatal. While spontaneous regression, likely due to immune defense activation, rarely occurs, we lack a biological rationale and predictive markers selecting patients for immune therapy. Experimental design: We performed unsupervised hierarchical clustering of global gene expression data from stage IV melanomas in 57 patients. For further characterization we used immunohistochemistry of selected markers, genome-wide DNA copy number analysis, genetic and epigenetic analysis of the CDKN2A locus and NRAS/BRAF mutation screening. RESULTS: The analysis revealed four distinct subtypes with gene signatures characterized by expression of immune response, pigmentation differentiation, proliferation or stromal composition genes. Even though all subtypes harbored NRAS and BRAF mutations, there was a significant difference between subtypes (p<0.01), with no BRAF/NRAS wild-type samples in the proliferative subtype. Additionally, the proliferative subtype was characterized by high frequency of CDKN2A homozygous deletions (p<0.01). We observed different prognosis between the subtypes (p=0.01), with a particularly poor survival for patients harboring tumors of the proliferative subtype compared to the others (p = 0.003). Importantly, the clinical relevance of the subtypes was validated in an independent cohort of 44 stage III/IV melanomas. Moreover, low expression of an a priori-defined gene set associated to immune response signaling was significantly associated to poor outcome (p=0.001). CONCLUSIONS: Our data reveal a biologically-based taxonomy of malignant melanomas with prognostic impact and support an influence of the anti-tumoral immune response on outcome.

Keywords

  • Cancer and Oncology

Other

Published
  • CREATE Health
  • ISSN: 1078-0432
Åke Borg
Åke Borg
E-mail: ake [dot] borg [at] med [dot] lu [dot] se

Principal investigator

Oncology and Pathology, MV

+46 46 275 25 52

MV 404 C21B2

90

Project manager

Familial Breast Cancer

90

Professor

Oncology and Pathology, MV

MV 404 C21C2

90