In 2003, evidence of tumors, including metastatic cancer, was discovered in fossilized "Brachylophosaurus" skeletons. Rothschild and co-workers tested dinosaur vertebrae for tumors using computerized tomography and fluoroscope screening. Several other hadrosaurs, including "Edmontosaurus", "Gilmoreosaurus", and "Bactrosaurus", also tested positive. Although more than 10,000 fossils were examined in this manner, the tumors were limited to "Brachylophosaurus" and closely related genera. The reason for this is not known.