Whale Size Linked To Lack Of Cancer Cells?

On the surface, it seems like a rather simple conclusion. While there are outside factors increasing the chances of developing cancer, basically, the bigger an animal is, the more cells it has, meaning an animal like a whale would get cancer more often than a dog. The more cells an animal has, the greater the chance for a cell mutation–cancer–to occur.

However, despite it sounding pretty simple, whales are showing that it might not be as straightforward as expected. Whales, despite their size, are some of the least likely animals to get cancer.

While people are experiencing cancer at a much higher rate in the modern era than ever before, it’s not a new disease. Scientists even found evidence of cancer dating back to 1.7 million years ago in ancestors of humans. Additionally, both domestic animals, like dogs and cats, and wild animals, such as eagles and whales, get cancer. There’s even some evidence of dinosaurs developing this disease.

There have been quite a few studies on why that’s the case. Known as Peto’s paradox, there is evidence that some larger animals including elephants and whales, develop cancer at much lower rates than expected for their size.

So what causes whales to resist cancer so much? It’s been a question for a long time, but scientists might now be closer to a theory, thanks to a group of Australian researchers.

These researchers analyzed the genes of blue and fin whales, some of the largest species out there, to try and discover their secrets to resisting cancer. What they found was that these larger animals have additional genes connected to their immune system. Additionally, whales have genes correlated to their size that other, smaller animals don’t have.

It’s thought that a whale’s cancer resistance might be a part of one of these genes. This means that there is a pretty good possibility that something to do with the whale’s size is also increasing their cancer resistance.

Likely, whales, or the ancestors of whales, developed cancer-resistant genes as they began to grow into larger and slower animals. It’s possible that whales had cancer at much higher rates than seen now, and it was killing off many groups before they could reproduce. So, as whales developed gene mutations to help them fight cancer, certain groups started to survive enough to reproduce and, therefore, pass on these genes.

Of course, genes are complicated. Sometimes, it only takes one gene to do something like reduce the chances of whales getting cancer, and sometimes, it’s a series of genes working together. It will likely take some more time before the exact answer is found, but the research does provide a good place for scientists to start focusing their studies.

Source: Into The Blue: Exploring genetic mechanisms behind the evolution of baleen whales