Do you know how many people are suffering from cancer? The number may be larger than what you expect. According to the
American Cancer Society [ACS] (2003), 1 of every 4 deaths in the US is from cancer, and there will be 556,500 deaths this
year, more than 1500 people per day. The high probability of developing this deadly disease can explain why it causes so many
deaths. In the US, men have a 1 in 2 risk of developing cancer throughout their lifetime, while for women the risk is more
than 1 in 3 (ACS 2003). But what if this risk could be reduced? A group of researchers at The Scripps Research Institute may
have the solution: a vaccine against cancer.
This newly developed vaccine targets and kills cancer cells by cutting off their blood supply (Niethammer et al. 2002),
since cancerous tumors cannot survive without necessary nutrients supplied by blood. To cut blood vessel formation, the vaccine
targets the endothelial cells (cells that make up the inside of blood vessels) of tumors. The endothelial cells possess unique
antigens (proteins on the surface of cells), which are inserted to the vaccine. When the vaccine reaches human body, the immune
system will present the antigens to anti-bodies called T-cells. T-cells will become activated and target the endothelial cells
by recognizing their antigens. T-cells then circulate through the bloodstream attacking the endothelial cells. Since different
types of tumors posses the same endothelial cells (McKeown 2002), T-cells can eliminate every kind of cancer cells.
Researchers conducted experiments on mice to test the effectiveness of this vaccine. Six mice were immunized with the vaccine
and then they received a potentially lethal dose of lung cancer cells. A control group of six mice received the same does
of cancer cells. After 30 days, all the mice in the control group died while every vaccinated mouse survived. Five of the
six survived mice received another dose of cancer cells 120 days after the first injection. No tumors were found in four mice,
and the remaining one possessed tumors on less than 10% of its lung surface. Furthermore, the four cancer-free mice showed
prolonged resistance of up to ten months (Niethammer et al. 2002). Although the vaccine is not 100% effective, these results
are encouraging.
Besides the cancer-fighting effect of the vaccine, these researchers also examined the possible side effects on fertility,
nervous system, and wound healing. The vaccine did not significantly affect the fertility of the immunized mice, which on
average had the same number of pups and took nearly the same time to give birth as compared with the control group. Similarly,
the tests on the body weight, balance, and overall behavior suggest that the nervous systems of the mice were not damaged
by vaccination. Finally, wounds inflicted on the backs of the vaccinated group took only one day longer to heal than wounds
on the control group. Despite this slight delay in healing, the wounds of the immunized mice healed without any complication
(Niethammer et al. 2002). These results suggest that the negative effects of the vaccine are minimal.
The experimental results indicate that the positive effects of the vaccine outweigh the negative ones. Although the vaccine
has only been tested in mice, the development of the vaccine has suggested an effective approach for preventing cancer. Using
the same cancer-fighting approach, scientists could easily develop a similar vaccine for humans. Although we have no guarantee
for a perfect vaccine, an anti-cancer vaccine is not a wish anymore.
Sources:
Niethammer A., Xiang R., Becker J., Wodrich H., Pertl U., Karsten G., Eliceiri B. & Reisfeld R. (2002).
A DNA vaccine
against VEGF receptor 2 prevents effective angiogenesis and inhibits tumor growth. Nature Medicine, Vol. 8, No. 12, 1369 –1375.
Stable
URL: http://dx.doi.org/10.1038/nm794
American Cancer Society (2003). Cancer Facts & Figures 2003. Retrieved January 21, 2003, from http://www.cancer.org/downloads/STT/CAFF2003PWSecured.pdf
Keith McKeown (2002). A Group at The Scripps Research Institute Designs DNA Vaccine that Inhibits Growth Of Cancerous
Tumors [Electronic Version]. The Scripps Research Institute Website. Retrieved January 21, 2003, from http://www.scripps.edu/news/press/110402.html
