Thirty-seven feline and 38 human spontaneous mammary gland
carcinomas were studied immunohistochemically. Commercially available
antibodies directed against high and low molecular weight
keratins (RCK-102 and NCL-5D3),
vimentin,
desmin,
glial fibrillary acidic protein (GFAP), neurofilament (NF)
proteins and muscle actin (HHF35) were used in the
avidin biotin peroxidase complex (ABC) technique on
formalin-fixed
paraffin wax-embedded tumour tissue samples. Healthy feline and human mammary gland tissue adjacent to the
neoplasms was also examined. The distribution pattern of
intermediate filament proteins and muscle actin was comparable in healthy mammary gland tissue of the two species: both RCK-102 and NCL-5D3
antibodies reacted with
luminal epithelial cells of ducts and acini, but basal/myoepithelial cells were stained by RCK-102 exclusively. In addition, basal/myoepithelial cells expressed
vimentin and muscle actin in both species, and GFAP was found in some feline basal/myoepithelial cells. No immunoreactivity to
desmin and NF
proteins was observed. Feline mammary gland
carcinoma cells reacted with RCK-102 (89%), NCL-5D3 (62%),
vimentin (76%) and GFAP (30%)
antibodies, while human mammary gland
carcinoma cells reacted with RCK-102 (95%), NCL-5D3 (100%) and
vimentin (13%)
antibodies. HHF35 immunoreactivity was observed in stromal cells only. These results indicate that mammary gland
carcinomas of both species share a heterogeneous immunophenotype with respect to
intermediate filament proteins, which adds to the list of known similarities between mammary gland
carcinomas of both species.