title: Constitutive (HO-2) and inducible (HO-1) haem oxygenase in pleomorphic adenomas of the human parotid: an immunocytochemical study.
abstract: This study examines the expression HO-1 and HO-2 isozymes in human parotid pleomorphic adenomas. They are members of the heat shock protein family, and are thought to play a role in the regulation of tumoral blood flow. Immunocytochemistry using antibodies specific for HO-1 and HO-2 were undertaken in 12 pleomorphic adenoma specimens, all sections of which contained adjacent normal salivary tissue. Normal salivary gland acini and ducts displayed significantly stronger immunoreactivity for HO-2 compared to tumour cells (p < 0.001). Expression for HO-1 was minimal in both normal salivary gland acini and tumour cells with no difference (p = 1.000). However, positive staining for HO-1 was seen in normal salivary ducts and in pleomorphic adenomas showing ductal differentiation. In conclusion, this is the first study to examine the expression of HO-1 and HO-2 within normal salivary glands and pleomorphic adenomas. Our findings suggest that HO may be implicated in the pathogenesis of salivary pleomorphic adenomas.
authors.affiliation: Department of Otolaryngology, St George's Hospital Medical School, London, UK. stephenlo@lycos.co.uk
authors.forename: Stephen
authors.initials: S
authors.lastname: Lo
authors.forename: Silvana
authors.initials: S
authors.lastname: Di Palma
authors.forename: Hafsa
authors.initials: H
authors.lastname: Yusuf
authors.forename: Andrew W
authors.initials: AW
authors.lastname: McCombe
mesh_terms: D008949:Adenoma, Pleomorphic / Q000201:enzymology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D015536:Down-Regulation; D005260:Female; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006801:Humans; D007124:Immunoenzyme Techniques; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D010306:Parotid Gland / Q000201:enzymology; D010307:Parotid Neoplasms / Q000201:enzymology*
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C105245:heme oxygenase-2