Melanoma inhibitory activity in melanoma diagnostics and therapy - a small protein is looming large.

Malignant melanoma is a highly aggressive cancer with a very poor prognosis after the onset of metastasis. We have previously demonstrated that the protein melanoma inhibitory activity (MIA) is involved in the metastasis of and immunosuppression in malignant melanoma. Recently, we further established MIA as a therapeutic target to inhibit metastatic spread in malignant melanoma. We could show that an inhibition of MIA by a synthetic peptide decreased both the number of metastases as well as immunosuppression in a murine model of malignant melanoma. To control recurrence after surgical resection of a primary lesion, it is paramount to have diagnostic tools available that can detect a relapse due to the strong metastatic potential of melanoma. This follow-up is maintained with periodic re-examinations. Due to high cost and the associated radiation exposure, radiology examinations are avoided if possible. The analysis of prognostic markers in patient serum is therefore attractive. In this review, we focus on the quantitative analysis of the MIA protein as a prognostic tool because it has proven to be a useful serum marker for documenting disease progression of malignant melanoma. The MIA quantification assay itself is readily performed using an ELISA kit and common laboratory equipment. Because analysing MIA serum levels in combination with other established markers such as S100B improves their prognostic value, we feel that the quantification of MIA in the serum, among other markers, should be performed as a general standard of care in patients at risk of developing metastatic melanoma.