[Role of osteopontin in the formation of microcalcifications in breast cancer].
BACKGROUND
Osteopontin, a non-collagen, Ca-binding phosphoprotein, plays roles in both physiological and pathological mineralisation processes. Its expression may be severely altered in malignant tumours.


OBJECTIVE
To investigate the presence of this protein in breast tumours showing mammographic microcalcifications.


METHODS
In this study the authors investigated immunohistochemically the osteopontin expression in 26 breast tumours. The elemental composition of the microcalcifications of the same tumours was also examined with energy dispersive spectrometer linked to a scanning electron microscope.


RESULTS
Osteopontin expression was found within the tumours in the tumour cells, in vascular smooth muscle cells, in the myoepithelial cells of the normal ducts, and in macrophages. Extracellular osteopontin positivity was seen around calcified foci. There was no correlation between osteopontin positivity and the examined prognostic factors: grade, type and size of the tumour, axillary lymph nodes status, or age. Two types of microcalcifications were seen: 1. Ca-phosphate only, 2. Those composed of various other elements.


CONCLUSIONS
The presence of osteopontin in the vicinity of calcified foci and in the vessel walls seems to support the hypothesis that osteopontin takes part in calcification process.
Tókés
Anna-Mária
AM
Semmelweis Egyetem, Altalános Orvostudományi Kar, II. Pathológiai Intézet, Budapest.
Krausz
Judit
J
Kulka
Janina
J
Jäckel
Márta
M
Kádár
Anna
A
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology*; D002114:Calcinosis / Q000378:metabolism*; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry* / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000737:chemistry / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D053495:Osteopontin; D012795:Sialoglycoproteins / Q000032:analysis*
C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D053495:Osteopontin