Exposure to cigarette smoke causes DNA damage in oropharyngeal tissue in dogs.

More than 40 mutagenic and carcinogenic agents present in cigarette smoke have been identified as causative factors of human cancer, but no relation has been clearly documented in companion animals. In dogs, in addition to smoke inhalation and transdermic absorption, exposure to smoke includes oral ingestion of particles adhered to the animal's fur. This study evaluates the presence and type of histological alterations and DNA integrity in oropharyngeal tissue in dogs exposed and non-exposed to household cigarette smoke by means of histopathology and comet assay studies on biopsy and swab samples.