Chondroitin-4-sulfate (CHSA), which is typically co-administered with glucosamine as a dietary supplement for osteoarthritis management, has been found to selectively enhance the tumor growth potential of BRAF V600E-expressing human melanoma cells in xenograft mice derived from patients or cell lines, as well as to impart resistance to BRAF inhibitors (Lin et al., 2018). The gene discussed is BRAF; the disease is melanoma.