Yes, they can. Not just vaccines though, any injection. Google fibrosarcoma for more information. This page for example:The Treatment of Feline Fibrosarcoma with Lipopolysaccharide and Cyclophosphamide;

"Fibrosarcoma remains an intractable and devastating disease both in human and veterinary medicine. In the domestic cat, fibrosarcoma has now been associated with the use of vaccines and the development of these tumours appears to occur in around 0.02% of vaccine injections (Hendrick et al, 1994)"

Also this is a good website with loads of articles and links:The Truth About Vaccines

For example this article:
http://www.truthaboutvaccines.org/docs/VaccineInfo.pdf

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