Possible relation of osteopontin to development of psammoma bodies in human papillary thyroid cancer.
BACKGROUND
Psammoma bodies are often observed in papillary carcinomas of the thyroid. Recently we reported that osteopontin (OPN) appears to play an important role in the development of psammoma bodies in meningiomas. Because the morphology and components of psammoma bodies in papillary carcinoma of the thyroid are similar to those of psammoma bodies in meningioma, we examined whether OPN was related to the psammoma bodies in papillary carcinoma of the thyroid.


METHODS
Expression of OPN mRNA was examined by Northern blotting and in situ hybridization. Immunohistochemistry was performed to localize the deposition of OPN protein and to identify the type of OPN mRNA-expressing cells.


RESULTS
The expression of OPN mRNA was detected in papillary thyroid carcinomas but not in normal thyroid tissue. Osteopontin mRNA-expressing cells were present around the psammoma bodies, and the localization of OPN protein was consistent with that of psammoma bodies. The OPN mRNA-expressing cells were identified as CD68-positive macrophages.


CONCLUSIONS
Osteopontin produced by macrophages may play a significant role in the development of psammoma bodies in papillary carcinoma of the thyroid.
Tunio
G M
GM
Department of Pathology, Osaka University Medical School, Suita, Japan.
Hirota
S
S
Nomura
S
S
Kitamura
Y
Y
D015152:Blotting, Northern; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002291:Carcinoma, Papillary / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D058574:Integrin-Binding Sialoprotein; D009999:Ossification, Heterotopic / Q000378:metabolism*; D015675:Osteocalcin / Q000378:metabolism; D015676:Osteonectin / Q000378:metabolism; D053495:Osteopontin; D012333:RNA, Messenger / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism*; D000097568:Matrix Gla Protein
D019485:Bone Morphogenetic Proteins; D002130:Calcium Phosphates; D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D058574:Integrin-Binding Sialoprotein; D015675:Osteocalcin; D015676:Osteonectin; D053495:Osteopontin; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D000097568:Matrix Gla Protein; C546871:IBSP protein, human; C506895:SPP1 protein, human; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous