Tumors can give themselves away early because they shed what are called circulating tumor cells (CTCs) into the blood stream. The trouble is, using current detection methods, it is difficult to distinguish tumor cells from white blood cells, since both are similarly sized and can stick to the same antibodies, according to the NCI Alliance for Nanotechnology in Cancer. Here, again, nanoparticles can save the day. Emory and Georgia Tech researchers have found that polymer-coated and dye-studded gold nanoparticles that are linked to a growth factor peptide rather than an antibody can detect CTCs in patients with head and neck cancer. "The key technological advance here is our finding that polymer-coated gold nanoparticles that are conjugated with low molecular weight peptides such as EGF [epidermal growth factor] are much less sticky than particles conjugated to whole antibodies," Dr. Shuming Nie is quoted as saying in the NCI article. "This effect has led to a major improvement in discriminating tumor cells from non-tumor cells in the blood." Article