Thursday, October 3, 2019

Universal Vaccine to Prevent Cancer

Cancer cases art credit: Canon Medical Systems USA, Inc.
Cancer Facts


Wouldn't it be a miracle if we had a vaccine that could prevent cancer?

We may soon have one.

Here's the story...

Discovery of new source of cancer antigens may expand cancer vaccine capabilities, Arizona State University, medicalxpress.com, 2 Oct 2019.

"What all of the cancer tumor mutations have in common is making neoantigens, or small protein fragments called peptides made inside a cancer cell that the host's immune system has never seen before. The aberrant peptides ——only found in cancer cells——can prime the immune system in a vaccine."

"Surprisingly, the source of these neoantigens was found not at the DNA level but rather, errors in the RNA of tumors."

For more than a decade, scientist Stephen Albert Johnston and his team at Arizona State University's Biodesign Institute have pooled their energies into an often scoffed-at, high-risk, high-reward goal in medicine: to develop a universal vaccine to prevent cancer.

The mindset is simple, according to Johnston. Treat cancer just like an infectious disease. So, when his team looked deep within tumors, their research gold was discovering 200,000 cancer neoantigens, the components of cancer vaccines, that had been missed by others. They also found that enough of these neoantigens occurred repeatedly in different tumors that it might be possible to make one vaccine for all tumors.

Now, in a new paper published in Scientific Reports, his research team has demonstrated the first experimental proof-of-concept bearing the fruit of their labors.

Their tour-de-force study examined mutations in more than 50 cancer cell lines, and 85 tissue samples from Mayo Clinic Arizona cancer patients, as well as the blood from patients from five different late stage cancer types: lung, breast, brain, gastric and pancreatic cancers.

They have found a common, new source of tumor mutations that could offer three levels of therapy with a cancer vaccine: 1) a broadly protective, or pan-cancer vaccine 2) cancer-type specific vaccines (e.g. breast vs. pancreatic), 3) personalized cancer vaccines based on mutations unique to an individual.

To discover the neoantigens in tumors, Johnston's team developed a new type of chip. They made chips that presented all of the 200,000 possible neoantigens, allowing them to simply screen for the antibodies in the blood patients raised against them. This is much simpler than the common practice which involves obtaining DNA from the tumor and sequencing it, a starting point for "personal cancer vaccines' that many companies are now pursuing.

"Personal cancer vaccines are complicated and expensive," said Johnston. "Also, only about 40% of tumors have enough mutations in the DNA to make a vaccine from. We discovered that even 'cold tumors' at the DNA level make lots of mistakes at the RNA level. And the mistakes we focus on are frameshift peptides which are much more immunogenic than the point mutations used in personal cancer vaccines. Most importantly, we can make off-the shelf vaccines for therapeutic or even preventative vaccines which will be much less expensive."

-more-

Kenny Rogers - The Gambler - 1979

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