Vaccinated against cancer?


Did you know that one of the first lines of defence against cancer is your own immune system?

So that got me thinking, why do we not treat cancer in the same way as we treat infections – with vaccines! Vaccination and antibody-based therapies would be a lot more specific than traditional chemotherapy and radiotherapy techniques, and therefore prevent many side effects.

Now, I’m sure many of you have heard of “cancer vaccines” before – heck, bet some of you have been given one. The Human Papilloma Virus (HPV) vaccination was rolled out across the UK for all young women a few years back. It works like any old vaccination; by improving immunity to HPV and thereby preventing it from causing cancer in the individual. However when I said cancer vaccine that’s not exactly what I meant.

I was thinking something along the lines of producing a vaccine that improves immune recognition of cancer itself, not just the viruses that cause it. Cancer cells are very complex, however, there are key molecules and pathways required for tumour formation in many, if not all, cancer cells. Initially, usually oncogenes and their pathways need to be activated and soon afte rtumour suppressor genes and their pathways need to be inhibited. Thus cancer usually begins by mutation of proto-oncogenes to produce active oncogenes. Therefore my idea of a cancer vaccine would be to produce a vaccine that improves immune recognition of these frequently found oncogenic proteins that lead to the initiation of cancer, and thereby improve the immune surveillance of cancer.

Antibodies bind to their corresponding antigen with a very high specificity, something which would be very useful in cancer treatment.

Obviously, as simple as this sounds, I could already think of multiple reasons why it might not work. Perhaps cancer cells mutate too quickly for a vaccination to be designed against them; perhaps oncoproteins are too similar to proto-oncoproteins and therefore it’s not possible to design a specific enough vaccine; perhaps there are problems with the oncoproteins being trapped within the cell. Nevertheless, I was curious as to whether somebody had tried.

So, I did some research.

Due to the fact that antibodies are thought to be too large to fit into the cell, it has long been held that any potential vaccination would have to target receptors or other proteins that are present on the surface of the cancer cell.

Guo et al. (2011), however, tested three intracellular proteins as immunogens that could be a potential target for a cancer vaccine.  PRL-3 (phosphatase of regenerating liver 3), a cancer-associated phosphatase; EGFP (enhanced green fluorescent protein), a general reporter; and mT (polyomavirus middle T), the polyomavirus middle T oncoprotein. It was found that these proteins were inhibited by their respective antibodies.

In 2012, a group of researchers from Vaxil Biotheraputics released a press release claiming they had come up with the “universal cancer vaccine”. They suggested it worked basically by priming the immune response against a protein that is found to be over-expressed on the surface of many cancer cells; mucin 1 (MUC1). In 2012, they were still in the process of clinical trails. However, even now, I am unable to find any real scientific literature, leading me to think think that maybe this is too good to be true?

Further Reading:
http://stm.sciencemag.org/content/3/99/99ra85.abstract

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