The warning signs of cancer in dogs are very similar to that in people. A lump or a bump, a wound that doesn’t heal, any kind of swelling, enlarged lymph nodes, a lameness or swelling in the bone, abnormal bleeding. Those are all classic signs. But sometimes there are little or no signs, at least early on. So any time an animal isn’t feeling well, or there’s something abnormal or not quite right, the owner needs to bring it to the attention of their veterinarian.