Quaternary Phosphonium Salts Outperformed Vemurafenib (PLX) and Etoposide Against BRAF&lt;sup&gt;V600D,V600E&lt;/sup&gt; PLX-Resistant Melanoma and MDR Neuroblastoma, Exhibiting No/Low Toxicity on 3T3/HaCaT Cells. Here, BRAF is linked to melanoma.