• Occupational exposure

    The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation. [From http://www.reference.md/files/D016/mD016273.html]
  • Oncogene

    A gene that is a mutated (changed) form of a gene involved in normal cell growth. Oncogenes may cause the growth of cancer cells. Mutations in genes that become oncogenes can be inherited or caused by being exposed to substances in the environment that cause cancer. [NCI]
  • Oncolytic virus

    A virus that can infect and multiply within cancer cells, leading them to die. These viruses may be manufactured or naturally occurring and can be used to target and destroy specific tumor cells. They may also induce an immune response. [Patient Resource LLC]