However, a long path has yet to be trod to validate plasmalemmal V-ATPase as a biomarker for Lf-based therapy, namely regarding its validation through in vivo studies and in rational clinical trials, the identification of the cancer types where Lf could be applied, the determination of administration route, the optimization of the dose and frequency, and the development of an effective high-throughput method for the detection of V-ATPase at the plasma membrane of cancer cells in clinical settings. This evidence concerns the gene LTF and cancer.