Can people get cancer? Not likely, but some animals can

Recent headlines about contagious cancers found in some animals might make you wonder: Can I get cancer? In Australia, Tasmanian devils die from aggressive facial tumors caused by an infectious virus. In the Atlantic, some shellfish have developed a form of leukemia caused by cancer cells suspended in the water. Scientists have known for years that dogs can transfer cancer cells from one to the other during intercourse.

“Despite recent headlines about cancer being contagious in other species, current data shows that it’s nearly impossible in humans,” says Dr. Glenn Weiss, director of clinical research and phase I and II clinical trials at our hospital near Phoenix. “There have been attempts to transfer cancer cells to people without cancer, and these attempts have not been successful.”

Controversial experience

In the 1950s and 1960s, New York immunologist Dr. Chester Southam conducted several controversial experiments by injecting live cancer cells into uninformed cancer patients and healthy prisoners. Although patients in both studies developed tumors, their immune systems were quickly attacked and killed. “Foreign cells are just as likely to be rejected as organ donation or bone marrow transplant from a donor,” Dr. Weiss says. “To take, the recipient will likely need significant immunosuppression.” Southam has been widely criticized for his experiments in humans and his medical license has been suspended for a year.

Organ recipients are at an increased risk of developing cancer, but only in rare cases has cancer been linked to an organ donor with cancer. Such cases are so rare that some cancer patients are still eligible to donate their organs. Some receptors develop into cancer because the body’s immune system is suppressed to help prevent organ rejection. Dr. James S. wrote. Welch, a radiation oncologist at Loyola University Health System in a 2011 article on infectious cancer: “Fortunately, survival of transplanted cancers in healthy humans is extremely rare and is documented by only a few cases.” “Therefore, friends and families of cancer patients and we, as caregivers of cancer patients, do not need to worry excessively about the remote possibility of ‘cancer.’”

infectious viruses

Humans can spread infectious viruses that lead to cancer. For example, human papillomavirus (HPV) is responsible for nearly all cases of cervical cancer. It is also associated with most cancers of the vagina and vulva and more than half of all penile cancers. The virus is also associated with 90 percent of anal cancers and 72 percent of oropharyngeal cancers. Hepatitis B and C viruses can cause hepatocellular carcinoma, the most common type of liver cancer.

Dr. Welch wrote that studying infectious cancers in animals could lead to a better understanding of the disease in humans. Why do dogs with CTVT generally fight disease, but Tasmanian devils with DFTD die within six months? DFTD has killed 90 percent of the species. Also, like human cancers, DFTD occurs in several species, and researchers have found that some Tasmanian devils can develop immunity to some species but not others. “The fine details of DFTD immunity combined with immunity to CTVT in dogs are important to their absolute scientific interest,” writes Dr. Welch. “Similarly, the natural resistance that humans have against transmissible malignancies…is of scientific interest.”