Comparative proteomic analysis reveals unique tumor protein composition among the melanoma subtypes pure desmoplastic and superficial spreading.

The U.S. death rate for melanoma has not decreased, despite the use of depth at biopsy and sentinel lymph node status to determine the risk of metastasis. Additional prognostic indicators and therapeutic targets are required, and identification of candidate proteins was the goal of this study. We utilized comparative mass spectrometry to compare five samples of each of two forms of melanoma, pure desmoplastic, which by depth at diagnosis has a favorable prognosis, and superficial spreading. Ontological analysis was applied to identify proteins and networks that were increased in one of the two subtypes. Analysis revealed a protein signature increase in pure desmoplastic melanoma associated with cell-to-cell binding and a signature increase in superficial spreading melanoma responsible for the cellular stress response including a constellation of heat shock proteins. The two subtypes of melanoma compared in this study have two unique protein compositions that correlate with their phenotypes. Further validation studies are warranted to evaluate the utility of identified proteins as prognostic markers and therapeutic targets.