PROM1 and melanoma: For example, CD133, a critical biomarker of MSC to maintain stemness properties and drug resistance, is reported to be upregulated in melanoma and involved in tumor growth, angiogenesis, and metastasis via mechanisms of PI3K/AKT and MAPK activation [76], suggesting inhibition of PI3K/AKT and/or MAPK signaling pathways not only targets melanoma with BRAF and NRAS or other gene mutations but also battles MSCs [29,30,33,76].