We’re talking differences that are noticeable not just to doctors and cancer researchers, but also to patients. Tumors in most cases form in the milk ducts, and their appearance can vary from leaf-like patterns to irregular star shapes. While women are most often diagnosed with breast cancer, it can also affect men (who account for about one percent of all cases), as well as companion animals.
Subtypes of breast cancer are generally identified according to the presence or absence of “receptors” known to fuel most breast cancers: estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2 (HER2). However, some patients develop a particularly aggressive tumor that does not exhibit any of the three. In what is called triple negative breast cancer, which forms as a result of chemotherapy, many of the more common treatments that are tailored to target one (or a combination of 2-3) of the tumor’s receptors are rendered ineffective. It disproportionately affects young African-American women—at triple the rate it’s diagnosed in women of other races—and in both humans and animals, it’s rare and carries a poor prognosis as compared with other forms of breast cancer. For years, researchers have struggled to find models in which to study the disease.
However, recent findings indicate one species may lead oncologists to a more comprehensive understanding of triple negative breast cancer: dogs. And another study further narrowed the focal point of researchers to a breed that is disproportionately affected by this subtype of breast cancer: shih tzus.
In recent years, cancer researchers have recognized that the wide variety of tumor subtypes suggests a need for new ways to develop treatments and medications designed for individual forms of the disease. Many combinations of new and existing drugs have been tested in efforts to replace treatments like chemotherapy—which, unfortunately, both causes triple negative breast cancer and is usually administered as part of its treatment.
A team of researchers at Virginia Commonwealth University’s Massey Cancer Center stumbled upon a new discovery. They were using mice to determine whether a drug called neratinib could be used to kill lung cancer cells that had become resistant to a different drug, afatinib. It worked. In fact, it worked much better than the scientists had hoped: in subsequent animal studies, they found neratinib enhanced the effectiveness of two drugs that, as it happened, Massey was testing in a phase 2 clinical trial for the treatment of triple negative breast cancer.
The team has since proposed a study that would investigate whether the three-drug cocktail (afatinib, pemetrexed, and sorafenib) would be as lethal for all types of advanced solid tumors (in other words: common subtypes of every kind of cancer from the skin to the pancreas to the brain).
In the meantime, consider the value of a potential new and more effective pharmacological therapy for women diagnosed with triple negative breast cancer. At present, the survival of patients beyond five years post-diagnosis hovers around 77 percent, while 93 percent of women will survive other types of breast cancer. And it’s even more deadly in canines.
It’s no accident that the study published by the scientists at Massey Cancer Center involved laboratory animal testing. As FBR has documented, the medical advancement represented in drastically improved survival rates for a variety of different cancers (cancers that affect men, women, children, and pets) are traceable directly to discoveries made with animal research. These include chemotherapy, surgeries to excise malignant tumors, cutting edge immunotherapy, stem cell therapies, new drugs, and combinations of new and/or existing drugs. Additionally, progress on these fronts is needed in the treatment of animals with breast cancer—which remains the most common type of cancer in female dogs, and is especially fatal in cats.
The humane use of dogs in research about breast cancer, including especially studies of the triple negative subtype, will likely yield promising results. Importantly, dogs also stand to benefit tremendously from new medical discoveries about these diseases. Think of the shih tzus.
National Breast Cancer Awareness Month is drawing to a close, but millions of breast cancer patients and their families will continue to be affected throughout the year. And considering the tremendous cost of the disease for both humans and animals, each of us has a responsibility to support the lifesaving work happening in research labs across the country and around the world—especially that which involves animal models.