The longest-living vertebrates that we know of – Greenland sharks – can live for centuries without ever developing cancer, and scientists have unveiled their secret. Spoiler alert: it’s in their DNA.
As it happens, a genomic study may have revealed how Greenland sharks (Somniosus microcephalus), the slow-moving water dwellers that can grow over six meters (20 feet) in length and more than one ton (2,205 lbs.) in weight, can live for 400 years cancer-free, per a New Scientist report on March 4.
Specifically, Shigeharu Kinoshita at the University of Tokyo in Japan and his colleagues have sequenced a Greenland shark’s genome, examining the genes in each chromosome, and reaching up to 37,000 genes found so far (86.5% completion).
400-year-old sharks’ genes
During the process, they have discovered a higher number of copies of genes involved in activating the NF-κB signaling pathway compared to other species, like the whale shark (Rhincodon typus) or the white-spotted bamboo shark (Chiloscyllium plagiosum), found to live to about 54 and 25 years, respectively.
Indeed, this pathway becomes involved when the body’s immune system reacts to threats and is present in processes like inflammation and tumor growth. In previous experiments, disrupting NF-κB has resulted in continuous tumor cell spread and pathogens dodging immune system defenses.
As Kinoshita explained,“since immune responses, inflammation, and tumor formation significantly affect aging and lifespan, the increase in genes involved in NF-κB signaling might be related to the Greenland shark’s longevity.”
Interestingly, bigger animals have been found to have a higher cancer risk, but have also evolved better defenses against it, and the recent study helps explain why, according to Aaron MacNeil at Dalhousie University in Nova Scotia, Canada.
Elsewhere, cancer research continues to advance and has included uncovering how RAS mutant proteins promote some of the deadliest cancers, exposing neurons that hinder treatment, and designing a new imaging technique for diagnosis inspired by butterfly wings – just to name a few.
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