ABCB1 and acute lymphoblastic leukemia: A study conducted in two acute lymphoblastic leukemia cell lines, CCRF-HSB-2 (T-ALL) and YAMN90 (B-ALL), found that ABCB1 mRNA increased upon activation of the MAPK/ERK pathway, indicating a potential interaction there [117]; however, it was not established if this regulation is direct or indirect.