Cancer affects not only people, but also the dogs we love. Canine cancer is becoming more common, and many families are searching for answers. One important piece of the puzzle is genetics.

Genetics help explain why some dogs develop cancer and others do not, even when they live similar lives.

Understanding this connection can help dog families:

• Recognize risk earlier
  

• Make informed care decisions

• Work closely with veterinarians on prevention and monitoring
  

What Is Canine Cancer?

Cancer happens when abnormal cells grow out of control. These cells can:

• Form tumors
  

• Spread into healthy tissues
  

Dogs can develop many types of cancer, including:

• Skin cancer
  

• Bone cancer
  

• Lymphoma
  

• Mammary gland tumors
  

Common Signs of Cancer in Dogs

Signs vary by cancer type and stage, but may include:

• New or growing lumps
  

• Swelling
  

• Weight loss
  

• Changes in appetite
  

• Low energy or lethargy
  

Early detection matters. Finding cancer early can improve treatment options and quality of life. Always consult a licensed veterinarian if something feels off.

What Affects a Dog’s Cancer Risk?

Cancer rarely has just one cause. It usually develops due to a combination of factors.

1. Genetic Factors

Every dog inherits genes from their parents. Some genes:

• Protect against cancer
  

• Increase cancer risk when mutations are present
  

Certain genetic mutations can make cancer more likely, especially in specific breeds. Understanding genetics helps veterinarians and researchers:

• Identify higher-risk dogs
  

• Improve screening and prevention strategies
  

2. Breed Predisposition

Some breeds are more likely to develop certain cancers due to shared genetic traits.

Examples include:

• Large and giant breeds → higher risk of bone cancer
  

• Some terrier breeds → higher risk of bladder cancer
  

Breed predisposition does not mean a dog will get cancer. It means:

• Awareness is especially important
  

• Monitoring may start earlier or happen more often
  

3. Environmental Factors

Genes are only part of the story. A dog’s environment also matters.

Risk-increasing exposures may include:

• Second-hand smoke
  

• Pesticides and harsh chemicals
  

• Too much sun exposure
  

• Poor or unbalanced diet
  

Reducing environmental risks can lower overall cancer risk, even in genetically predisposed dogs.

How Genetics Contribute to Cancer Development

Genetics influence cancer in several key ways:

Tumor Suppressor Genes

• These genes help control normal cell growth
  

• When they stop working properly, cells can grow unchecked
  

Oncogenes

• These genes promote cell growth
  

• Mutations can cause cells to divide too quickly
  

DNA Repair Genes

• These genes fix mistakes when cells copy DNA
  

• If damaged, mutations can build up and lead to cancer
  

Epigenetic Changes

• These affect how genes are turned “on” or “off”
  

• They do not change DNA itself, but they can influence cancer risk
  

Inherited Mutations

Some dogs inherit mutations that raise their cancer risk. These mutations do not guarantee cancer, but they increase susceptibility.

Breed-Specific Cancer Risk

Research shows that some breeds have higher rates of specific cancers due to shared genetics.

Examples include:

• Retrievers → higher risk of lymphoma and hemangiosarcoma
  

• Boxers → higher risk of mast cell tumors and intestinal cancers
  

• Giant breeds → higher risk of aggressive bone cancers
  

Knowing these patterns helps families and veterinarians:

• Watch for early signs
  

• Start screenings sooner
  

• Make proactive health decisions

Genetic Testing and Canine Cancer

Genetic testing can offer helpful insights, but it is not perfect.

Benefits of Genetic Testing

• Identifies dogs at higher risk
  

• Supports earlier monitoring

• Helps guide responsible breeding
  

• Allows for personalized prevention plans
  

Limitations of Genetic Testing

• Not all cancer-related genes are known
  

• Results can be complex and confusing
  

• Genetics do not account for environmental factors
  

Genetic testing should always be used alongside veterinary guidance, not as a standalone answer.

Preventive Steps Dog Families Can Take

While genetics cannot be changed, many risk factors can be managed.

Reduce Environmental Risks

• Avoid second-hand smoke
  

• Limit exposure to harsh chemicals
  

• Create a clean, low-toxin home
  

Support a Healthy Weight

• Obesity is linked to higher cancer risk
  

• Balanced nutrition and regular movement matter
  

Schedule Regular Veterinary Visits

• Routine exams help catch changes early
  

• Screening plans may vary by breed and age
  

Feed a Nutritious Diet

• High-quality, balanced food supports immune health
  

• Fresh, whole ingredients can be beneficial
  

Stay Observant

• Get to know your dog’s normal body and behavior
  

• Report new lumps, changes, or concerns promptly

A Compassionate Reminder

Cancer is complex, and no single factor causes it. Genetics, environment, and lifestyle all play a role. Learning about these factors empowers families to take thoughtful, proactive steps while working closely with veterinary professionals.

At the Drake Dog Cancer Foundation, we believe that knowledge, compassion, and early awareness can make a meaningful difference—for dogs and the people who love them.

If you ever have concerns about your dog’s health, please consult a licensed veterinarian for guidance and care.

References

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Davis BW, Ostrander EA. Domestic dogs and cancer research: a breed-based genomics approach. ILAR J. 2014;55(1):59-68. doi: 10.1093/ilar/ilu017. PMID: 24936030; PMCID: PMC4158346.

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