Molecular pathology of malignant melanoma: changing the clinical practice paradigm toward a personalized approach

Melanocytic proliferations are notoriously difficult lesions to evaluate histologically, even among experts, as there is a lack of objective, highly reproducible criteria, which can be broadly applied to the wide range of melanocytic lesions encountered in daily practice. These difficult diagnoses are undeniably further compounded by the substantial medicolegal risks of an "erroneous" diagnosis. Molecular information and classification of melanocytic lesions is already vast and constantly expanding. The application of molecular techniques for the diagnosis of benignity or malignancy is, at times, confusing and limits its utility if not used properly. In addition, current and future therapies will necessitate molecular classification of melanoma into one of several distinct subtypes for appropriate patient-specific therapy. An understanding of what different molecular markers can and cannot predict is of the utmost importance. We discuss both mutational analysis and chromosomal gains/losses to help clarify this continually developing and confusing facet of pathology.