A recent study has found that there are similarities between pre-malignant mammary lesions in canines and humans. These findings indicate that dogs may be ideal models to study progression of the disease while it is still treatable, according to Sulma Mohammed, DVM, an associate professor in comparative pathobiology at Purdue University School of Veterinary Medicine.
“Dogs develop these lesions spontaneously in contrast to other available models and are exposed to the same environmental risk factors as humans,” Mohammed said. “These shared features make the dog an ideal model to compare the breast lesions that will progress to cancer and those that will regress. Such a model will facilitate customized treatment and prevention strategies.”
Dogs also have shorter life spans than people, making it possible to study mammary lesions and invasive tumors that develop after a few years instead of decades, she said.
The researchers focused on the precancerous, or preneoplasia, lesions in tissue around the tumor and not the tumor itself. They studied 212 tissue biopsies from 200 female dogs with tumors that were retrieved from the archives of the Purdue Animal Disease Diagnostic Laboratory and the Veterinary Teaching Hospital, as well as from the Institute of General Pathology and Anatomical Pathology at Sassari University.
The canine slides were then compared to human specimens collected from the Department of Pathology at the Indiana University School of Medicine.
The research team found that preneoplasia lesions are virtually identical, microscopically, in dogs and women.
“Establishing an animal model is paramount for testing new treatment and prevention modalities, especially for lesions that express none of the targeted receptors, such as triple-negative types, before human clinical trials,” she said.
The main form of treatment of breast cancer tumors has been surgical removal. Mohammed and colleagues would like to find out if there is a way to identify the lesion early with noninvasive screening, such as ultrasound or magnetic resonance imaging.
Mohammed’s next step is to determine the prevalence of lesions in dogs with no tumors. She also plans to study cats, which have a 90 percent malignancy rate when they are diagnosed with breast cancer.
The research, which appears in the November issue of the Journal of Cancer Epidemiology, Biomarkers and Prevention, was funded by the U.S. Department of Defense.