Mechanisms of resistance to BRAF and MEK inhibitors and clinical update of US Food and Drug Administration-approved targeted therapy in advanced melanoma.

Approximately 50% of melanomas harbor an activating BRAF mutation. Combined BRAF and MEK inhibitors such as dabrafenib and trametinib, vemurafenib and cobimetinib, and encorafenib and binimetinib are US Food and Drug Administration (FDA)-approved to treat patients with BRAF V600-mutated advanced melanoma. Both genetic and epigenetic alterations play a major role in resistance to BRAF inhibitors by reactivation of the MAPK and/or the PI3K-Akt pathways. The role of BRAF inhibitors in modulating the immunomicroenvironment and perhaps enhancing the efficacy of checkpoint inhibitors is gaining interest. This article provides a comprehensive review of mechanisms of resistance to BRAF and MEK inhibitors in melanoma and summarizes landmark trials that led to the FDA approval of BRAF and MEK inhibitors in metastatic melanoma.

Invasive Basal Cell Carcinoma of the Skin Treated Successfully with Vismodegib: A Case Report.

INTRODUCTION: Basal cell carcinoma (BCC) is the most common skin cancer. It is primarily a local disease, and it very rarely causes metastatic disease. Chemotherapeutic agents had limited success in management of metastatic disease until the introduction of vismodegib. In this case report, we describe the presentation of a metastatic BCC that was not amenable to surgical resection or local treatment options and was treated successfully with vismodegib. CASE PRESENTATION: A 69-year-old white man was referred to our surgical clinic for evaluation of an erosive left shoulder lesion. Biopsy in the clinic showed BCC with evidence of metastases on positron emission tomography-computed tomography scan. Tumors had invaded multiple bony structures and multiple organs, making surgical resection not an option. The decision was made to treat the patient with vismodegib. At 1-year follow-up, the patient's left shoulder lesion had improved with no evidence of metabolically active distant metastasis. DISCUSSION: Although BCC is the most common skin cancer, it is usually a local disease and treated with local measures. Metastatic BCC is extremely rare, and in cases when surgical resection or local radiation are not viable options, chemotherapeutic agents typically offer very limited improvement. Vismodegib is an oral selective sonic hedgehog pathway inhibitor that shows benefit in patients with locally advanced or metastatic disease.