A low molecular weight agent with antineoplastic activity. Benzoylphenylurea binds to the colchicine binding site on tubulin, thereby blocking tubulin polymerization and disrupting mitotic function. This agent also inhibits DNA polymerase, and has been shown to arrest leukemia cells in the G1-S transition phase of the cell cycle. Check for active clinical trialsusing this agent. or A chemical that comes from certain substances when they are not burned completely. It is found in car exhaust, smoke from wood fires, tobacco, oil and gas products, charred or grilled foods, and other sources. It may also be found in water and soil. Benzo(a)pyrene can cause a skin rash, a burning feeling, skin color changes, warts, and bronchitis. It may also cause cancer. It is a type of polycyclic aromatic hydrocarbon. Also called 3,4-benzpyrene.