Immunohistochemical study of carbohydrate antigen 19-9 in salivary gland tumors

Objectives: The expression of carbohydrate antigen 19-9 (CA 19-9)has been studied immunohistochemically in carcinomas of pancreas, colorectum, gastric mucosa, endometrium, thyroid gland and upper aerodigestive tract.The serum levels of CA 19-9 can be used to diagnosis and management of patients with pancreatic and colorectal carcinomas. The preoperative Ca 19-9 serum level has been found to correlate with a poor prognosis of pancreatic and colon cancer. The pattern of expression of CA 19-9 in gastric and pancreatic carcinomas has been found to correlate with its serum levels whereas in colorectal carcinomas with the prognosis. The aim of this study was to investigate immunohistochemically the pattern of expression of CA 19-9 in salivary gland neoplasms in an attempt to determine its usefulness as prognostic indicator. Methods: Twenty-one benign salivary gland tumors and 43 malignant, fixed in 10% formalin and embedded in paraffin were retrospectively studied with hematoxylin-eosin stain and the streptavidin-biotin-complex method using the monoclonal antibody 19-9 (Signet).Twenty-three out of 64 cases of salivary gland tumors ( 11 benign and 12 malignant) contained adjacent normal salivary glands. In addition 5 normal salivary glands which obtained from reasons others than neoplasia were examined. Results: The antigen was expressed in mucous acinar and ductal cells in a diffuse and granular pattern. Apical expression was observed occasionally in the luminal cells of intercalated and striated ducts and usually in excretory ductal cells. In 20 out of 23 cases of salivary gland neoplasms the tumor cells and adjacent normal salivary glands expressed CA 19-9. The pattern of expression of the antigen in benign and malignant tumors was similar to that in normal salivary glands. Conclusions: It is suggested that the pattern of expression of CA 19-9 in malignant salivary gland tumors could not be used as a prognostic indicator.