字幕表 動画を再生する 英語字幕をプリント Cancer is a serious disease, but can I catch it by playing basketball with my friend who has it? Of COURSE I can't. I never play basketball. Sup guys, Trace here at the YouTube Space in Los Angeles. Just changing things up a bit, trying some new things at DNews. I was being glib earlier, but it's not entirely a joke. In the 90s, a lack of education about the HIV and AIDS epidemic in the U.S. saw people believing they could contract the disease by sharing a basketball with Magic Johnson. Now, some media outlets are repping the news that cancer might be contagious, but stop worrying; in humans, cancer is definitely not contagious. In the 1970s, the humble clam created quite a wash of press when it was discovered they were developing leukemia at a fantastic rate. Researchers from Columbia University suggested it wasn't a virus causing cancer, but that the CANCER ITSELF was contagious -- and they were right! Contagious cancer is extremely rare. With a few exceptions, the cancer cells themselves are host specific, meaning if an organism dies from cancer, the cancer dies too. Scientists found this new contagious cancer when they scooped up these maladapted molluscs and tested their tumors; finding they were all the same genotype! The cells are clones! They believe a sad little clam developed a type of cancer which, somehow, continues cell division outside of the clam's body. The tumor cells divide and are swept away in the ocean currents, occasionally encountering other clams, latching on and dividing more -- causing cancerous tumors in previously unaffected clams. This is a clam nightmare scenario. This is only the third time scientists have found contagious cancers; but don't worry, none are primate-born. 11,000 years ago, genetic maladaptation in a dog evolved and was spread to other dogs -- just like the clams, it somehow was able to jump from dog to dog and still afflicts them to this day. Yes, dogs can catch cancer from each other. Canine Transmissible Venereal Tumor (CTVT) was documented 200 years ago, and has been seen on dogs on every continent. The cancer develops a cauliflower-shaped bleeding tumor on the dog's genitals. When the dogs mate, or just hump, the tumor spreads like an STI and infects the new host, eventually causing another tumor. Over the last 11,000 years, CTVT has evolved and lives as a parasite in the dogs body, eventually disappearing -- that's not the case for the second type of infectious cancer. Tasmanian devils, which are real, not just a cartoon -- they don't even spin! You lied to me Looney Tunes! Tasmanian Devils can catch cancer from their fellows, poor devils, when they bite each other in competition over food. Devil facial tumour disease (DFTD) is an infectious cancer which has somehow evolved a cloaking device as described by National Geographic. The cancer cells lack a group of proteins which identify foreign cells to the immune system called MHC -- without them the immune system doesn't attack, the cancer takes hold, facial tumors develop and are so intense the animals can't eat -- causing death. Cancer is a extraordinarily broad term for abnormal cell growth caused by unfortunate genetic mutations in cells. You can increase the likelihood of errors by exposure to radiation, smoking, stress, obesity, viruses, smoking, or other carcinogens; but as of yet there are NO KNOWN CONTAGIOUS TUMORS in primates or humans; though bacteria like Helicobacter pylori can increase the chances of developing stomach cancer; and a few of the strains of HPV famously increase chances of cervical cancer. // GET VACCINATED // But, they're not contagious cancers; they just make conditions more favorable to develop cancer. What do you want to know more about? Have a science question? An Idea for a future show? Let me know in the comments. And while you're thinking about tumors -- why not learn EXACTLY what they are? Some are benign, some aren't and you might have one in you RIGHT NOW -- Julia lays it all out in this video. Thanks for watching DNews!