The present invention refers to cells from a subpopulation of progenitors of endothelial cells loaded with gold nanoparticles sensitive to excitation with infrared radiation with consequent release of thermal energy, to a composition having a plurality of these cells and to their use in the diagnosis and treatment of solid tumours thanks to the selective localization of the composition in the tumour mass, which can be thus identified easily for diagnostic purposes by marking the cells with appropriate marking agents, or treated by stimulation with pulsed laser beam up to the complete cauterization of the tumour mass for a targeted and highly effective therapeutic action.
