PGP and gastric cancer: Further associations between ERK and ABC transporters were demonstrated in gastric cancers, where activated ERK1/2 induces MRP1 and BCRP [122], in acute myeloid leukemia, where ERK1/2 up-regulates Pgp and MRP1 [123], and in ovarian cancer, where the inhibition of ERK1/2 and AKT lowers the levels of BCRP [124].