The basal expression of P-gp facilitates efflux of DOX out of the cell, minimizing its intracellular concentration (Fig 1).[10] Further, repeated DOX exposure leads to the upregulation of P-gp, conferring resistance to the cell that leads to the high rates of tumor recurrence observed clinically once chemotherapy is removed.[2,11,12]. The gene discussed is PGP; the disease is neoplasm.