IMMUNOHISTOCHEMICAL DETECTION OF P53 OVEREXPRESSION IN PARAFFIN WAX-EMBEDDED SQUAMOUS-CELL CARCINOMAS OF CATTLE, HORSES, CATS AND DOGS

One hundred and six squamous cell carcinomas (SCCs) of cattle, horses, cats and dogs were analysed immunohistochemically for overexpression of p53 protein. The monoclonal antibody pAb 240, which recognizes only mutant p53, was used. Of 41 bovine ocular SCCs, 26 (63.4%) showed p53 nuclear reactivity. All of six (100%) equine ocular SCCs and seven of nine (77.7%) SCCs of the equine penis or vulva gave positive reaction s. In nine of 11 (81.8%) feline SCCs of the ear and in seven of 14 (50 %) feline SCCs of other locations, p53 immunoreactivity was detected. Only seven of 25 (29.5%) canine cutaneous SCCs gave a positive reactio n. Thus p53 antigen could be detected immunohistochemically in formali n-fixed and paraffin wax-embedded tissues of SCCs of domestic animals. The results support the view that, as in man, p53 overexpression play s an important role in the development of most SCCs of the animal spec ies studied. This was in particular true for feline SCCs of the ear an d for bovine and equine ocular SCCs, which are assumed to be related t o ultraviolet radiation. (C) 1996 W.B. Saunders Company Limited