Most common nanoparticles for theranostic purposes in breast, lung, and prostate cancer: (1) core-shell NPs, (2) metal NPs for Magnetic Resonance Imaging (MRI) contrast, (3) mesoporous NPs, (4) liposomes, (5) polymer nanocapsules, (6) micelles, (7) quantum dots, (8) functionalized NPs; strategies for specific targeting: (A) enhanced permeation and retention effect, (B) functionalization with specific ligands, (C) functionalization with monoclonal antibodies; and main diagnostic applications of NPs for those cancers: (MRI) Magnetic Resonance Imaging, (FL) Fluorescence Imaging, (PET/SPECT) Positron-Emission Tomography/Single Photon-Emission Computer Tomography, (PhAc) Photoacoustic Imaging.