In 2002, three leading SV40 experts (Drs. Gazdar, Butel and Carbone) who have been involved in studying SV40 for a number of years wrote:
“t is our opinion that SV40 should be included in the list of group 2A carcinogens that is, those that are probably carcinogenic to humans.”
-- Gazdar AF, Butel JS, Carbone M., SV40 and human tumours: myth, association or causality? Nat Rev Cancer. 2002 Dec;2(12):957-64.
This group (2A) is part of the classification scheme provided by the International Agency for Research on Cancer (IARC), which is part of the World Health Organization. IARC’s mission is to coordinate and conduct research on the causes of human cancer, the mechanisms of carcinogenesis, and to develop scientific strategies for cancer control. IARC also publishes a monograph series that provides a ranking system for carcinogenic substances.
Group 1: The agent (mixture) is carcinogenic to humans. The exposure circumstance entails exposures that are carcinogenic to humans.
Group 2A: The agent (mixture) is probably carcinogenic to humans. The exposure circumstance entails exposures that are probably carcinogenic to humans.
Group 2B: The agent (mixture) is possibly carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans.
Group 3: The agent (mixture, or exposure circumstance) is not classifiable as to carcinogenicity in humans.
Group 4: The agent (mixture, exposure circumstance) is probably not carcinogenic to humans.
Substances in Group 2A include a number of toxic chemotherapy drugs, viruses, and other recognizable substances. Examples include:
Chemotherapy in Group 2A
Bischloroethyl nitrosourea (BCNU)
Viruses in Group 2A
Human papillomavirus types 31, 33
Kaposi's sarcoma herpesvirus/human herpesvirus 8
Lead compounds, inorganic
Creosotes (from coal-tars)