SV40 in human tumors: new documents shed light on the apparent controversy

Presently there are over 61 reports from 49 different laboratories that have detected SV40 in human mesothelioma, lymphoma, brain and bone tumors, versus three reports (two from Dr. Shah's laboratory who performed his study under contract from Dr. Strickler at the Viral Epidemiology Branch (VEB) National Cancer Institute (USA) that have failed to detect SV40 in some of these same tumor types. To address whether the negative reports were caused by lack of sensitivity of the technique used in Shah's laboratory, or whether the positive reports were caused by contamination within the greater number of laboratories reporting SV40 detection, two multi-center studies were conducted. The first study, Testa et al., 1998, confirmed the presence of SV40 in mesothelioma. The second study, Strickler et al., produced irregular results indicating that: (a) though never reporting SV40 detection to date, Dr. Shah's laboratory reported the most sensitive technique of all participating laboratories; (b) all participating laboratories essentially agreed the DNA extracts provided under contract to the VEB were negative; (c) all participating laboratories agreed one-half of the negative controls prepared by the VEB contract laboratory were positive due to contamination by the contract laboratory. In addition, (d) the authors concluded the laboratories previously detecting SV40 in human tissue specimens were not reporting contamination. Scientists in the field have since debated how these seemingly contradictory results were produced.

During the course of litigation representing patients with SV40-positive tumors, the author obtained correspondence among members of the VEB multi-center study and sworn testimony by Dr. Shah that address some of the incongruities of the study.

Dr. Shah's laboratory technique used in 1996 was apparently not sufficiently sensitive to detect SV40 in human tumors. When this became apparent, during unilateral pre-trial testing of positive controls by Dr. Shah, the study coordinator of the VEB, Dr. Strickler, apparently compromised the blinded nature of the study and allowed Dr. Shah to modify and improve his technique. When one of the participating laboratories questioned irregularities in the data from Dr. Shah's laboratory and directly questioned Dr. Strickler, the study organizer, about the potential irregularity, Dr. Strickler and Dr. Shah offered letters stating that such irregularities had not occurred and re-confirmed that they had not deviated from the standard protocol.

The facts indicating that Dr. Shah's laboratory technique was not sufficiently sensitive to detect SV40 were not made available to the other laboratories participating in the study and were not published. Instead, according to Dr. Shah's testimony, Dr. Strickler, the VEB multi-center study coordinator, compromised the masked positive controls and knowingly permitted Dr. Shah to re-test and adjust his technique during pre-trial testing. The actual negative pre-trial test results were never published alongside the published trial results indicating Dr. Shah's laboratory had the most sensitive technique to detect SV40 among the nine participating laboratories.