Iron is important for DNA synthesis and cell cycle progression, hence, tumor cells have a high requirement for iron to sustain their proliferation.[57] The expression of iron importers, Dmt1 and Tfr1, increased and iron exporter, Fpn, decreased in colonic tumors of DSS-treated mice (Fig. 7A-C) suggesting that there was increased iron uptake by the tumors. This evidence concerns the gene SLC40A1 and neoplasm.