Cancer is a leading cause of deaths. Millions of people are diagnosed with cancer every year. Many cancer cells have a protein all over their surface, while healthy cells typically do not express the protein as strongly. By conjugating, or binding, the gold nanoparticles to an antibody the researchers were able to get the nanoparticles to attach themselves to the cancer cells which may help us unravel the inner workings of a cancer cell and produce better treatments. In terms of drug delivery systems, nano particles enable unique approaches for cancer treatment. A large number of nanoparticle delivery systems have been developed for cancer therapy and currently they are in the preclinical stages of development. More recently developed nanoparticles are demonstrating the potential sophistication of these delivery systems by incorporating multifunctional capabilities and targeting strategies in an effort to increase the efficacy of these systems against the most difficult cancer challenges. This article reviews the available preclinical and clinical nanoparticle technology platforms and their impact on cancer therapy.