Sipholenol A did not act on KB-3-1 epidermoid drug-sensitive carcinoma cells (which do not express P-gp) and on MRP1-expressing KB-CV60 cells, so the researchers suggested that this triterpenoid is selective for P-gp and consider the sipholenol A as a potential P-pg modulator [13]. The gene discussed is OCA2; the disease is carcinoma.