Melanoma gene expression and clinical course

Evidence for the in vitro lymphocyte response against autologous melanoma has been accumulating over the past 10 years, leading to the identification of numerous melanoma-associated antigens recognised by T cells. These antigens are targets for specific immunotherapy protocols. However, their expression is heterogeneous during tumour progression and may contribute to therapeutic escape mechanisms and disease progression. This study was designed to chart the importance of these escape mechanisms, and to assess the relationship between gene expression and the clinical profile (especially survival data) of patients with melanoma. We studied the expression of certain melanoma genes in tissue biopsies from 202 patients using reverse transcriptase-polymerase chain reaction (RT-PCR). The evaluated genes were Melan-A, tyrosinase, Na-17A, MAGE-1, MAGE-3 and Ny-ESO-1. We then correlated the results to the patients' survival data. 202 samples (cutaneous, nodal and visceral biopsies) were analysed by RT-PCR. No relationship was found between clinical data and gene expression. No relationship was found between survival data and gene expression, when samples of all stages were combined in the analysis. However, interactions between gene expression and disease stage were significant. When stage III samples alone were considered, MAGE-3 expression alone or in association with the expression of the other tumour-specific genes was found to be significantly associated with a higher disease-free survival (respectively, P = 0.0349; 0.007). Our results provided no evidence for a relationship between gene expression and clinical data, or between gene expression and survival data. However, with regard to certain sub-groups, such as stage III samples, tumour gene expression was significantly associated with survival.