Low incidence of SV40‐like sequences in ependymal tumours

Abstract

Between 1955 and 1963, millions of children and adults were exposed to SV40-contaminated poliovirus vaccines. The oncogenic potential of this polyomavirus was revealed when intracerebral inoculation of SV40 into newborn hamsters resulted in the development of ependymomas and choroid plexus papillomas. Subsequently, SV40-like sequences were repeatedly detected in human ependymomas with broadly ranging incidence rates of 7-90%. Most epidemiological studies, however, have not described an increased occurrence of ependymomas. To gain more data on this controversial issue, this study examined 62 archived ependymal tumours from 31 children and 31 adults who underwent surgery between 1990 and 1999. Only three (5%) of the tumours--including 24 classical, 20 anaplastic, and 12 myxopapillary ependymomas; one subependymoma; and five ependymoblastomas--revealed subgenomic SV40 sequences. None of the ependymomas in patients born between 1920 and 1960 demonstrated SV40-like sequences. The positive tumours represent 7% of grade II and III ependymomas (two paediatric and one adult tumour). DNA sequencing of the PCR product revealed identical sequences of SV40 in the positive ependymal tumours. Compared with the results from other countries, this incidence rate is relatively low. Therefore, it seems likely that significant differences between individual countries exist regarding the prevalence of SV40-positive ependymomas. These differences may reflect different degrees of exposure to SV40-contaminated polio vaccine.

Low prevalence of SV40 in Swiss mesothelioma patients after elimination of false-positive PCR results

“…However, one sample set was re-evaluated using 1 g DNA [40], and this did not result in improved detection of SV40 [24]. In conventional PCR, the inclusion of 1 g DNA did not always warrant positive findings [10,18], while smaller DNA inputs did not necessarily lead to negative results [11], in particular with low quality DNA from paraffin-embedded tissue [16,19,20,41]. It should also be noted that amplification of non-specific bands has been reported for commonly used SV40 primers with DNA inputs above 250 ng [10].…”

Absence of simian virus 40 in human brain tumors from northern India

“…In our study and the Austrian study, 10 all of the specimens were fixed in formalin, which could have degraded the DNA. However, few tumors in the German studies were SV40 ϩ , despite use of fresh frozen specimens, 9,11 and other studies using only formalin-fixed tissues yielded positive results. 7,26 Our quantitative testing for the human gene GAPDH indicated that most of our specimens had adequate PCR-amplifiable DNA.…”

Evidence for a role of the Simian Virus 40 in human breast carcinomas

“…The set of primers RA1 (nt 266-245) and RA2 (nt 5,195-5,218) targets the SV40 regulatory region; it allows the distinction between archetypal SV40 strains containing, only a 72-bp insert motif (expected size of PCR product 242 bp), and laboratory-adapted SV40 strains, with duplicated 72-bp insert sequence (expected size of PCR product 314 bp) [46,47]. The set of primers LA1 (nt 2,251-2,274) and LA2 (nt 2,545-2,522) amplify a 294-bp sequence in the VP1 gene encoding the major capsid protein of the virus.…”