Simian virus 40 (SV40), which contaminated polio vaccine widely distributed between 1955 and 1962, does not seem to have increased the likelihood of an exposed person developing the blood cancer non-Hodgkin lymphoma (NHL), according to a report from the National Cancer Institute.

The new findings support those from another recent study that showed no link between use of another SV40-tainted vaccine and NHL, mesothelioma, or brain tumors. There had been concerns that the virus may promote these malignancies because SV40 DNA had been found in various tumor specimens.

In a population-based study reported Tuesday in the Journal of the National Cancer Institute, Dr. Eric A. Engels, from the NCI in Rockville, Maryland, and colleagues tested for anti-SV40 antibodies, indicating exposure to SV40, in blood samples obtained from 724 patients with NHL and from 622 matched “controls” without NHL.

The samples were tested at two independent laboratories. The two labs, respectively, reported positive results for 7.2 and 9.8 percent of NHL patients, and for 10.5 and 9.6 percent of the control group - so the virus was not associated with increased NHL risk.

Further analysis showed that SV40 exposure was not linked to any particular type of non-Hodgkin lymphoma, either, the researchers state.

The results suggest that SV40 is not a major cause of NHL, although Engels’ team acknowledges that they couldn’t test for the presence of the virus in actual tumors because they didn’t have enough specimens.

SOURCE: Journal of the National Cancer Institute, September 15, 2004.