Note that mRNA technology is not limited to viruses. The cancer vaccine is actually a misnomer as it is actually a personalized treatment for people who already have cancer [1]:
> The cells from the patient's tumor are analyzed, and genetic sequencing is used to identify twenty neoantigen epitopes that may elicit the strongest immune response in the patient. The sequences encoding the twenty patient-specific epitopes are transcribed and loaded onto a single mRNA molecule. [...] This leads to an induction of both cytotoxic T-lymphocyte (CTL)- and memory T-cell-dependent immune responses that specifically target and destroy the patient's cancer cells that express these neoantigens.
BioNTech has actually started Phase 2 trials for a mRNA-based cancer therapy [2].
[1] https://www.cancer.gov/publications/dictionaries/cancer-drug...
[2] https://www.clinicaltrialsarena.com/news/first-patient-dosed...