CARTA Members in the News: Drs Nissi and Ajit Varki (UC San Diego School of Medicine)

Dec 10, 2020

Comparative anthropogeny helps shed light on cancer risk.

For many years, scientists have struggled to explain why humans are much more prone to cancers than our closest evolutionary cousins, the chimpanzees. Now a team led by UC San Diego researchers and CARTA Members, Drs Nissi and Ajit Varki (Ajit is also CARTA co-director), has discovered a possible reason, and it all comes down to a protein-coding gene gone rogue. The proteins in question are cell surface markers produced by the SIGLEC12 gene and play a role in self vs invader identification of cells. At some point during human evolution, a mutation prevented this gene from recognizing these differences, wreaking havoc in the immune system. While most of these mutations were removed by way of natural selection, a minority of people still retain the bad copy, making them more susceptible to cancer even in the absence of other risk factors. Chimpanzees, however, maintain the healthy version of SIGLEC12 with no ill effects.

You can read more in the UC San Diego Health Newsroom: "Evolution May Be to Blame for High Risk of Advanced Cancers in Humans" (Buschman, H. 08 Dec. 2020) or check out the Open Access article: Siddiqui, S.S., Vaill, M., Do, R., Khan, N., Verhagen, A.L., Zhang, W., Lenz, H.‐J., Johnson‐Pais, T.L., Leach, R.J., Fraser, G., Wang, C., Feng, G.‐S., Varki, N. and Varki, A. (2020), Human‐specific polymorphic pseudogenization of SIGLEC12 protects against advanced cancer progression. FASEB BioAdvances.


Jones, A. 01, April 2021. Editor's Choice in Cancer Biology: "Rogue" Protein Could Contribute to Humans' High Cancer Rates. The Scientist.

Celine. T. 15 Dec. 2020. Human Evolution Could Be to Blame for Being Prone to Cancer, Study Says. The Science Times