ABCC4 and neoplasm: Importantly, it is of value to note that enforced Dd-mrp4 expression is capable of suppressing significantly growth in all of the tumor cell lines (Caco-2, A549, HeLa, and HepG2 cells), though the levels of growth suppression is somewhat different depending on the tumor cell lines used: the most remarkable suppression of growth was noticed in HepG2 cells (Figure 4).