Why 'sharks get cancer, mole rats don't'

May 6, 2016, Loyola University Health System
Cover of "Sharks Get cancer, Mole Rats Don't". Credit: NA

A provocative new book by Loyola Medicine radiation oncologist James S. Welsh, MD, Sharks Get Cancer, Mole Rats Don't: How Animals Could Hold the Key to Unlocking Cancer Immunity in Humans, explores how animals can help us understand how the immune system can be used to fight cancer.

Dr. Welsh is a professor in the Department of Radiation Oncology of Loyola University Chicago Stritch School of Medicine.

After publication, the book initially was named to Amazon's list of Hot New Releases in Oncology and Medical Research and reached No. 1 on Barnes & Noble's lists of new books in Immune System Physiology and Immunology.

"Dr. Welsh explores the scientific history of cancer like never before," said Norman Wallis, PhD, executive director of the American College of Radiation Oncology. "With examples ranging from galaxies to dinosaurs, creepy mammals to disgusting sea creatures, and even particle physics, he weaves a story as good as any novel. And it comes together in a way that suggests a future cure for cancer."

Dr. Welsh explores fascinating examples of how, in both and humans, the immune system in some cases effectively kills tumor cells, while in other cases cancer cells escape detection. He also explains how, contrary to popular belief, it's possible to catch cancer—as in the case of Tasmanian devils (marsupials in Australia the size of small dogs).

Tasmanian devils are on the verge of extinction due to a virulent form of contagious cancer. Similarly, clams on the Atlantic seaboard are vanishing due to a contagious leukemia transmitted in sea water. Dogs can contract a contagious cancer as well, but usually overcome it spontaneously. Thereafter, the dogs become impervious to this type of cancer, providing an intriguing clue about the role of the immune system in cancer.

Animals offer many tantalizing clues about the nature of cancer in humans. Contrary to myth, sharks do get cancer. But naked and blind mole rates generally are not susceptible to the disease. In humans, an uncommon form of dwarfism called Laron syndrome confers near total cancer immunity. In another unusual phenomenon, a man died from ovarian cancer after receiving a kidney transplant from a woman who had the disease. In an even odder case, a tapeworm developed "cancer," which spread throughout the patient's body. And in perhaps the book's most extraordinary case, Dr. Welsh describes the seemingly miraculous cure of one of his patients, named Daniel, who had advanced metastatic melanoma. (Dr. Welsh first wrote about the case in a 2014 Discover magazine article.)

The highly aggressive cancer had spread to Daniel's liver and bones, and he appeared to have only a few months to live. Daniel suffered excruciating pain from a tumor in his femur (thigh bone). Dr. Welsh offered Daniel local radiation to shrink the tumor, relieve the pain and reduce the risk of a fracture. This palliative treatment was intended only to relieve symptoms, not cure the disease. But three months later, a CT scan found no trace of cancer anywhere. Daniel benefitted from a rare phenomenon called the abscopal effect, in which localized treatment not only shrinks the targeted tumor but distant tumors as well. It appears the local radiation somehow stimulated Daniel's immune system to attack cancer throughout his body.

"The abscopal phenomenon represents an extreme example of the immune system's ability to recognize and occasionally overpower even highly advanced cancer," Dr. Welsh writes.

Earlier attempts to fight cancer with immunotherapy were disappointing. These treatments strengthened the , but also boosted the strength and number of previously unrecognized or underappreciated immunological guardian cells that actually protect the tumor.

However, newer approaches to immunotherapy are showing promise. "Years of skepticism about immunotherapy are finally fading. . ." Dr. Welsh concludes. "The revolution is on!"

Sharks Get Cancer, Mole Rats Don't is published by Prometheus Books and distributed by Penguin Random House.

Explore further: Radiation combined with immune-stimulating drugs could pack a powerful punch against cancer cells

Related Stories

Radiation combined with immune-stimulating drugs could pack a powerful punch against cancer cells

March 21, 2016
In his final State of the Union address, President Obama tasked Vice President Joe Biden with leading a new National Cancer Moonshot initiative. The hope is that this will put America on course to be "the country that cures ...

Common prostate cancer treatments suppress immune response and may promote relapse

April 8, 2016
Prostate cancer patients and their doctors may want to think twice about the best timing for chemotherapy or radiation therapy in conjunction with a common nonsurgical treatment, based on international research findings led ...

Innate immunity may help limit cancer growth

September 17, 2015
Cancer immunotherapy, a relatively new frontier in cancer treatment, works by enhancing the capacity of one's immune system to attack cancer cells. To date, this field has focused on developing cancer vaccines or engineering ...

Engineering T cells to treat pancreatic cancer

April 18, 2016
Dr. Sunil Hingorani, a member of the Clinical Research and Public Health Sciences divisions at Fred Hutchinson Cancer Research Center, will present recent groundbreaking developments in treating pancreas cancer with engineered ...

No proof that radiation from X rays and CT scans causes cancer

February 3, 2016
The widespread belief that radiation from X rays, CT scans and other medical imaging can cause cancer is based on an unproven, decades-old theoretical model, according to a study published in the American Journal of Clinical ...

Recommended for you

Study tracks evolutionary transition to destructive cancer

February 23, 2018
Evolution describes how all living forms cope with challenges in their environment, as they struggle to persevere against formidable odds. Mutation and selective pressure—cornerstones of Darwin's theory—are the means ...

Researchers use a molecular Trojan horse to deliver chemotherapeutic drug to cancer cells

February 23, 2018
A research team at the University of California, Riverside has discovered a way for chemotherapy drug paclitaxel to target migrating, or circulating, cancer cells, which are responsible for the development of tumor metastases.

Lab-grown 'mini tumours' could personalise cancer treatment

February 23, 2018
Testing cancer drugs on miniature replicas of a patient's tumour could help doctors tailor treatment, according to new research.

An under-the-radar immune cell shows potential in fight against cancer

February 23, 2018
One of the rarest of immune cells, unknown to scientists a decade ago, might prove to be a potent weapon in stopping cancer from spreading in the body, according to new research from the University of British Columbia.

Putting black skin cancer to sleep—for good

February 22, 2018
An international research team has succeeded in stopping the growth of malignant melanoma by reactivating a protective mechanism that prevents tumor cells from dividing. The team used chemical agents to block the enzymes ...

Cancer risk associated with key epigenetic changes occurring through normal aging process

February 22, 2018
Some scientists have hypothesized that tumor-promoting changes in cells during cancer development—particularly an epigenetic change involving DNA methylation—arise from rogue cells escaping a natural cell deterioration ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.