Treatment consisting of both BRAF and MEK inhibitors improves efficacy in treating metastatic melanoma as the addition of a MEK inhibitor neutralizes the paradoxical MAPK pathway activation that occurs due to BRAF inhibition.6 For that reason, combination treatment reduces the risk of tumorigenesis in other tissues, such as the development of squamous cell carcinoma.19 However, the occurrence of a treatment-associated serous retinopathy increased with this combination, supporting the notion that this adverse event is most likely to be an on-target treatment effect of MAPK targeted drugs.20 This evidence concerns the gene BRAF and metastatic melanoma.