Detection of alkaline phosphatase in canine cells previously stained with Wright-Giemsa and its utility in differentiating osteosarcoma from other mesenchymal tumors.
BACKGROUND
Osteosarcoma (OSA) is a common primary bone tumor in dogs. Demonstration of alkaline phosphatase (ALP) reactivity by tumor cells on unstained slides is useful in differentiating osteosarcoma from other types of sarcoma. However, unstained slides are not always available.


OBJECTIVE
The objectives of this study were to evaluate the diagnostic utility of detecting ALP expression in differentiating osteosarcoma from other sarcomas in dogs using cytologic material previously stained with Wright-Giemsa stain and to assess the sensitivity and specificity of ALP expression for diagnosing osteosarcoma using a specific protocol.


METHODS
Archived aspirates of histologically confirmed sarcomas in dogs that had been previously stained with Wright-Giemsa stain were treated with 5-bromo, 4-chloro, 3-indolyl phosphate/nitroblue tetrazolium (BCIP/NBT) as a substrate for ALP. Cells were evaluated for expression of ALP after incubation with BCIP/NBT for 1 hour. Sensitivity and specificity of ALP expression for diagnosis of OSA were calculated.


RESULTS
In samples from 83 dogs, cells from 15/17 OSAs and from 4/66 tumors other than OSA (amelanotic melanoma, gastrointestinal stromal tumor, collision tumor, and anaplastic sarcoma) expressed ALP. Sensitivity and specificity of ALP expression detected using BCIP/NBT substrate applied to cells previously stained with Wright-Giemsa stain for OSA were 88 and 94%, respectively.


CONCLUSIONS
ALP expression detected using BCIP/NBT substrate applied to previously stained cells is useful in differentiating canine OSA from other mesenchymal neoplasms.
Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA. julia.ryseff@colostate.edu
Julia K
JK
Ryseff
Andrea A
AA
Bohn
D000469:Alkaline Phosphatase / Q000032:analysis* / Q000378:metabolism; D000818:Animals; D001399:Azure Stains; D044963:Biopsy, Fine-Needle / Q000662:veterinary; D001859:Bone Neoplasms / Q000473:pathology / Q000662:veterinary*; D001842:Bone and Bones / Q000473:pathology; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D007202:Indicators and Reagents; D007211:Indoles; D009363:Neoplasm Proteins / Q000378:metabolism; D009580:Nitroblue Tetrazolium; D012516:Osteosarcoma / Q000473:pathology / Q000662:veterinary*; D012189:Retrospective Studies; D012509:Sarcoma / Q000473:pathology / Q000662:veterinary; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
D001399:Azure Stains; D007202:Indicators and Reagents; D007211:Indoles; D009363:Neoplasm Proteins; D009580:Nitroblue Tetrazolium; C035455:5-bromo-4-chloro-3-indoxyl phosphate; D000469:Alkaline Phosphatase