Because of the failure so far to find effective treatment for patients with advanced stages of melanoma, increasing efforts have been made to find prognostic factors identifying patients in the risk zone for development of metastasis.

This thesis investigates the prognostic powers of a few selected serological and immunohistochemical biomarkers.

In the first and second study, patients operated on for localized malignant melanoma were investigated regarding the prognostic impact of angiogenic serological markers and circulating levels of S100. We concluded that the S100 assays, especially S100BB, are potential biomarkers in patients with malignant melanoma, correlated to both survival and disease free survival. However, no such conclusion could be drawn from the first study, where we found no correlation to survival and investigated angiogenic markers.

In the third and fourth study four new potential immunohistochemical biomarkers where investigated in collaboration with the Swedish Human Protein Atlas Program, and those where TRP-1, galectin-1, DLG5 and syntaxin-7.

We found that TRP-1 correlated inversely with tumor stage and galectin-1 correlated to Ki-67.

DLG5 showed a significant inverse correlation to Ki67 and the expression of STX7 was inversely correlated to tumor stage, suggesting that decreased expression is associated with more aggressive tumors.

None of the investigated markers in study III and IV correlated with disease free survival or overall survival.

In the fifth and last study, we examined the expression of SOX10, a transcription factor, in different melanocytic lesions. Also, a proliferation assay was carried out in a human melanoma cell line. The results reveal the presence of SOX10 in different melanocytic lesions, with a weak inverse correlation to survival and a significant inverse correlation to T-stage. A significant decrease in proliferation rate for SOX10 silenced cells was found and our data also suggests an increased migratory response in SOX10 silenced cells.