The first published report to establish a link between infection with a virus and the regression of cancer appeared in 1912. Reviewed in [1,2,3,4,5,6] This report described a woman whose cervical cancer improved following treatment to prevent rabies. The woman had been bitten by a dog, and she was subsequently injected with a vaccine made of attenuated (i.e., weakened) rabies virus. Over the next 60 years, many other viruses, including Newcastle disease virus (NDV), were shown to have anticancer potential.[7,8,9,10,11,12] Reviewed in [1,3,4,5,6,13,14,15,16,17,18,19,20,21,22,23,24,25] The first report of positive results using NDV as a treatment for human cancer was published in 1964. By that time, attenuated strains of NDV had been used for almost 2 decades to prevent Newcastle disease in birds, and the inability of this virus to cause serious illness in humans had been established.
As indicated previously (refer to the General Information section of this summary for more information), cells infected with NDV can be killed directly by the virus or indirectly through an immune system response to the infection. The immune system uses a variety of approaches to kill virus-infected cells, including attack by cytotoxic cells (i.e., natural killer cells and/or cytotoxic T cells); attack by antivirus antibodies, which are made by B cells; and the release of cytokines. Reviewed in [2,6,15,18,22,25,26,27,28]
Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the formal ranking system used by the PDQ Editorial Boards to assess evidence supporting the use of specific interventions or approaches. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Cytokines can be directly cytotoxic to virus-infected cells (e.g., tumor necrosis factor [TNF] -alpha Reviewed in [14,15,20]). In addition, they can stimulate increases in the activity and/or numbers of specific types of immune system cells (e.g., interferon -alpha, interferon-gamma, and TNF-alpha Reviewed in [2,29,30,31]).
As also indicated previously (refer to the General Information section of this summary for more information), if the immune system is responding to virus-infected cancer cells (or fragments of cancer cells), then better recognition of tumor-specific antigens may occur, and an increased ability to kill uninfected cancer cells may be acquired. Reviewed in [15,18,19,23,26,30,32,33,34,35,36,37,38] The immune system would use the same approaches to kill uninfected cancer cells that it uses to kill virus-infected cells. For example, it has been shown that TNF-alpha is directly cytotoxic to some, but not all, cancer cells, whereas normal cells are not harmed by this cytokine.[39,40,41,42]