Understanding Animal Health: A Glimpse into Veterinary Science

Caitlin White
Jul 8
6 min read

This story contains themes such as cancer; pet loss, and medical descriptions. Please read at your own discretion, and seek help when you are struggling with or triggered by one of the themes discussed at:

https://www.rspca.org.uk/adviceandwelfare/pets/bereavement/coping

https://www.nhs.uk/mental-health/feelings-symptoms-behaviours/feelings-and-symptoms/grief-bereavement-loss/

Many students dream of working with animals, whether as veterinarians, animal care specialists, or researchers. Learning about the health challenges animals face, such as cancer, helps us appreciate the important role veterinarians play in keeping our pets healthy. By understanding what happens when animals get sick, we can better support our pets and consider how we might help animals in our future careers.

What is a recent issue affecting our pets?

One significant, current issue is a rise in Canine non-Hodgkin's Lymphoma (non-HL) has been recorded recently. A shocking 90% of all hematopoietic neoplasms, which are tumours that arise from blood-forming or lymphoid cells, are associated with non-HL. Even more appalling, dogs are diagnosed with non-HL two to five times more frequently than humans. So, the question remains: why is lymphoma the most common cancer on the rise?

Canine non-Hodgkin’s Lymphoma comes from the lymphatic system, namely the lymph nodes and lymphatic organs such as the spleen. Another key source of lymphoma is in the bone marrow. Canine non-HL arise from lymphocytes, similarly to humans. Lymphocytes are specialised cells, otherwise known as white blood cells, which are responsible for targeting pathogens (any disease-causing microorganism), masses or foreign bodies. When genetic mutations take place in these lymphocytes, cancer occurs.

There are different types of lymphoma in dogs. These include: multicentric (multiple lymph nodes), gastrointestinal, mediastinal (in the chest), and extranodal (outside lymphatic system).

There are five stages associated with non-HL, from stage one where a single node is affected (very rare!) to stage five where the bone marrow, nervous system, liver and spleen are affected. Unfortunately, Stage IV or Stage V is the deadliest. Chemotherapy can help many dogs reach remission; however advanced stage low-grade lymphomas can be incurable.

Treatments

As with humans, dogs need chemotherapy! Glucocorticoids are used to promote cell apoptosis (cell death). There is also monotherapy (a single drug or treatment) with medications. Some drugs are orally administered, and others are given intravenously in a hospital setting. With treatment, remission is possible with a survival time of 8-9 months.

How to keep our pets safe

Interestingly, the increased incidence and risk factors are very similar to human non-HL. Several environmental factors, linked to owner habits and the how the dog lives, affect cancer rates.

Dogs who live in industrial areas, exceeding the EPA ozone limits with high levels of 1,3 -butadiene and formaldehyde, have an increased risk of non-HL. Other dangerous areas include households near waste incinerators, polluted sites ,and radioactive areas. All cause DNA expression alterations, be it with the release of carcinogens or toxic chemicals, like PFAs and dioxins.

Although there is a weak association, one might never guess the danger lurking in your very own house – bleach. Mixed with other cleaners or organic matter, bleach can release carcinogenic gases and volatile compounds. Another household risk hides in your garden, namely insecticides and herbicides. Specifically, 2,4 – D – herbicides used in gardens have been studied. It has been found that dogs excrete a biological dose of the chemical, which cause changes in DNA, disrupts hormones, leads to chronic inflammation and gene mutations. In a 2013 study, Scottish Terriers who were exposed to herbicide on their lawns had up to 7 times greater chance of cancer.

Another surprising risk would be the concept of “second-hand smoking”, a common risk associated with human cancers. However, dogs are also at risk of tobacco smoke. It has been found that urinary levels of cotinine (a metabolite of nicotine), was excreted by dogs in households with owners who smoke. However, this also has a weak association as with bleach.

Weight, body condition and diet obviously have a major impact on non-Hodgkin’s Lymphoma. Since obesity is an inflammatory condition, overweight dogs are at a predisposition to cancer. It was also found that dogs who ate homemade food, instead of breed-specific and supportive diets curated for dogs, had an increased risk of non-HL. Weak body condition was also a major risk factor.

As with all diseases, there is a genetic component to non-Hodgkin’s Lymphoma. Certain breeds like Boxers, Golden Retrievers, Rottweilers (and many more) are predisposed to non-HL. It was also found that it can even be carried in families of dogs! With canine B-cell lymphoma, a certain gene called TRAF3 has been isolated, which contributes to the development of the cancer. This gene controls DNA transcription, cell survival and cytokine production. Furthermore, there have been studies linking genetic mutations of enzyme activity, as well as epigenetic changes, with non-HL. A less common genetic factor would be aneuploidy, which is an abnormal number of chromosomes.

Awareness and finding out more...

There are still numerous questions and possibilities for study around canine non-Hodgkin’s Lymphoma. The risk factors leading to canine non-HL, and the increased incidence, are still being studied in depth. No-one quite understands the exact mechanism of the cancer and the reasoning behind development, especially the increased rate of development in this day and age. Another remarkable and rapidly developing area of study would be the use of canine models to study non-Hodgkin’s Lymphoma in humans. The cancer between the two species is strangely similar, and one can help the other to advance research of causes and new treatments. Other unanswered questions include the reasons behind chemotherapy resistance developed by dogs and humans with non-HL. There is also a large area of research surrounding novel treatments, like T-cell therapies, in both humans and dogs. Not only is it the most common cancer but understanding and awareness of the disease is very important, for people with or without a furry friend!

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Figure 1: ChatGPT (2022) A dog with a purple canine lymphoma awareness ribbon. Generated using GPT-5 series (Accessed: 14 March 2026)