Dear OncoLink "Ask The Experts,"
My champion bichon frise age 12 recently died of a mammary gland tumor with adenocarcinoma which wound up in aggressive tumors in the front leg joints. Can you tell me if there is any evidence of mammary gland tumors having any hereditary links? I have a grand daughter with a pea sized lump which will be excised asap. Both were spayed at age 6 after 3 litters. Is there any chance this is hereditary?
Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:
There is nothing in the veterinary literature regarding the heritability of susceptibility to mammary carcinoma. The closest information is that smaller breed dogs are more commonly affected than larger breed dogs. By far, the most important factor in susceptibility is age at the time of spaying: spaying any time prior to the third heat coveys some protection, and spaying before the first heat reduces the risk to almost nothing.