LTF and cancer: To address our hypothesis, we assessed the effect of bovine Lf (bLf) on cell proliferation, apoptosis induction, extracellular acidification rate, intracellular pH, as well as the localisation of V-H+-ATPase in three different breast cell lines, namely the highly metastatic cancer cell line Hs 578T, the poorly metastatic cancer cell line T-47D, and the non-tumorigenic cell line MCF-10-2A.