Background

Malignant melanoma is a genetically diverse disease. The most frequent mutation is BRAF (60%), followed by NRAS (30%) and cKIT (5%) mutations (1). While BRAF, NRAS and cKIT mutations represent the largest fraction of patients, for whom targeted therapies can be proposed using BRAF, MEK or cKIT inhibitors respectively (2), there is also an important group of patients lacking all of these three mutations, referred to as the triple wild type population (3xWT). These patients cannot currently benefit from the wealth of targeted therapies, except immunotherapies, and hence are in dire need for potential actionable targets. In order to better describe this important group of patients, we made use of the database of Caris Molecular Intelligence^™. In this platform the tumors of patients were analyzed by next generation sequencing (NGS) of select hotspot mutations and also protein expression of selected protein markers by immunohistochemistry (IHC) including expression of PD-L1.