Gene expression profile changes between melanoma metastases and their daughter cell lines: implication for vaccination protocols.

Vaccination protocols based on autologous tumor material often require in vitro culturing of tumor cells to obtain enough cellular material for the production of the vaccine. Cancer cells and particularily melanoma cells are known for their genomic instability. Therefore, it can be assumed that melanoma cells acquire genomic changes and thereby changes in the transcriptome during in vitro culturing. This may lead to a shift of epitopes expressed on the tumor cells. We analyzed the transcriptome of in vitro cultured melanoma cells prepared from melanoma metastases. Comparing the gene expression changes between the tumors and their offspring cell lines, we demonstrate that with increasing passage numbers, gene expression changes increase drastically.