I don’t know how prestigious the journal is since it started in 2020 but here’s what they are talking about:

https://publichealthpolicyjournal.com/biontech-rna-based-covid-19-injections-contain-large-amounts-of-residual-dna-including-an-sv40-promoter-enhancer-sequence/

I don’t know if characterizing it as “cancer viruses” is very accurate