MTOR and cancer: The ability to use fluorescence-based imaging techniques such as confocal and multiphoton microscopy, Fluorescence Lifetime Imaging Microscopy (FLIM) and Light Sheet Fluorescence Microscopy (LSFM) represents a very powerful, insightful and novel avenue for drug target investigation and development, for both mTOR pathway studies and its associated protein-protein and protein-drug interactions and cancer therapy [43,44].