Chromosomal aberrations involved in the development and progression of several human malignancies are a well known and intensely investigated fact. Some of these alterations are specific for a certain disease, allowing improved diagnosis and/or prognosis. Compared to the large number of publications dealing with human cytogenetics, cytogenetic investigations in neoplasias of the dog are rare. Nevertheless, there is a number of publications indicating that canine tumors are likewise affected by chromosomal aberrations.

We have investigated a number of canine neoplasias of different origins, e.g., mammary tumors, skin tumors, oropharyngeal tumors, prostatic tumors, and hematopoietic diseases. Three of these entities (Skin tumors, prostatic tumors and hematopoietic diseases) showed a gain of chromosome 13 material, indicating a possible involvement of canine chromosome 13 in the development and progression of canine neoplasias. This is of notably interest, since there is evidence that dogs with hematopoietic diseases that exhibited trisomy 13 as primary aberrations show significantly longer duration of the first remission and of survival length compared to animals with other chromosomal changes, because of better response to a given chemotherapy.

Thus, combining the results in the literature with the results presented in this review it is likely to assume that the canine chromosome 13 might contain a gene or a group of genes which could be involved in tumor development. Interestingly, canine chromosome 13 shares homology to the terminal region of human chromosome 8q, a chromosomal region frequently involved in the onset of several human malignancies.