Cancer is caused by abnormal mutation, growth and uncontrollable division of cells, disrupting normal functioning of biological environment of them. WHO says that cancer is the 2nd most common cause of death globally, with millions of people worldwide suffering from it. Some scientists believe that environmental changes and pollution in the modern era has increased number of cancer occurrences across the globe. However, humans existing during the very beginning of mankind are also known to have suffered from cancer. The disease kills not just humans, but also fish, reptiles, some birds, dogs and cats. Dinosaurs may too have suffered from cancer at times, according to recent discoveries.
Experts explain how weight, height and age of an individual are a contributing factor in development of cancer. Among animals, whales, porpoises and elephants, despite their massive sizes, rarely develop cancer. Elephants have 20 copies of tumor-suppressing genes that do not allow cancer to form. Humans have just one copy of this gene. To understand why whales do not suffer from the deadly disease, skin sample from a female, adult humpback whale named Salt was analyzed by researchers, led by Marc Tollis, who performed RNA and DNA sequencing on it for assembling a genome map. On completion of the task, data was compared to information on genetic makeup of several mammals that included sperm, bowhead and blue whales. It was seen that particular genomic loci, regulating proliferation, cell cycle and in-cell DNA repair processes, evolve faster in whales than in other mammals. Whales also have several duplications of genes that suppress development and growth of cancerous tumors.
Understanding these anti-oncogenic mechanisms that prevent cancer in whales can help scientists and researchers in coming up with anticancer therapies and preventive strategies for effectively fighting cancer in humans, hopefully sometime in the near future. The team of researchers hopes to continue experimenting with whale cell lines in laboratories, so that they may develop prototypical cancer drugs based on biological self-defense mechanisms of the aquatic mammals.