Designing a cancer vaccine

The great blogger known as owlposting has an awesome new podcast episode with Alex Rubinsteyn and Ben Vincent, two scientists who work on cancer immunotherapy, on ‘How to design a cancer vaccine’. The general idea behind a cancer vaccine is to prevent cancer cells from evading the immune system by training patients’ own immune cells to recognize them and kill them off.

Unfortunately, many past attempts to develop personalized cancer vaccines have failed. This is in part because they were designed based on the genetic profiles of cancer cells, rather than the actual proteins those cancer cells expressed on their surface. Measuring which proteins were actually presented would typically require samples to be collected differently than they usually are (fixed with formalin, rather than frozen) and the measurement was expensive and, in older versions, not very accurate. There were other problems too: mRNA vaccines were a new platform and faced their own regulatory scrutiny and immune cells were hard to steer well. They tend to over-respond to just a few target mutations, which might distract immune cells from the real ones, or they might be set loose on the wrong ones, which could be dangerously toxic.

But now, things might be different. Prediction and measurement have gotten better, the mRNA platform has been tested in billions of people, and there’s a clearer regulatory path for personalized drugs. I really enjoyed the episode and feel cautiously hopeful. It’s also worth listening to hear about how weird cancer cells are: they can, for example, reawaken ancient viral DNA buried in our genomes or even switch on genes that are normally only active in the sperm or placenta. You can listen here.