Osteopontin

Osteopontin is a32k-Da3 alpha(v)beta3 integrin adhesion molecule. It mediates cell-matrix interactions, binding integrins and CD44. Overexpression seems to enhance tumour dissemination. Invreasd expression correlates with high stage and poor prognosis in non-small cell carcinoma of lung and other malignancies3.

Immunohistochemical expression

Osteopontin is overexpressed in carcinomas of lung, breast, colorectum, stomach and ovary, and in melanoma. High levels of expression correlate with tumour invasion, progression and metastases. Osteopontin is expressed by most mesotheliomas.

Organ	tumour type	Osteopontin
Brain		6/102
Breast	ductal carcinoma	3/262
Larynx	squamous cell carcinoma	1/32
Lung		12/172, 76/983
Mesothelioma	Epithelial	19/201
	Mixed	15/161
	Sarcomatoid	2/21
	Overall	36/381, 36/383
Lip	squamous cell carcinoma	7/92
Mouth	squamous cell carcinoma	12/192
Tongue	squamous cell carcinoma	14/222
Salivary gland		3/142
Pharynx	squamous cell carcinoma	2/52
Oesophagus	squamous cell carcinoma	7/102
Stomach	adenocarcinoma	11/112
Colon	adenocarcinoma	17/202
Liver		4/92
Bile duct carcinoma		1/12
Pancreas	adenocarcinoma	13/162
Ovary	serous cystadenocarcinoma	13/222
Endometrium	adenocarcinoma	10/142
Kidney	renal cell carcinoma	26/362
Renal pelvis	transitional cell carcinoma	14/172
Bladder	transitional cell carcinoma	33/332
Prostate	adenocarcinoma	12/282
Skin		4/6(4 melanomas, 2 basal cell carcinomas)2
Thyroid		0/22

Diagnostic utility

Potentially of use in the diagnosis of mesothelioma1. Serum levels are reportedly higher in those exposed to asbestos with mesothelioma than those without. Immunohistochemical positivity is common in mesothelioma1 but the corresponding studies of reactive mesothelium have not yet been done.

References

1 Pass HI, Lott D, Lonardo F, et al. Asbestos exposure, pleural mesothelioma, and serum osteopontin levels. N Engl J Med 2005; 353:1564-73

2 Coppola D, Szabo M, Boulware D, et al. Correlation of osteopontin protein expression and pathological stage across a wide variety of tumor histologies. Clin Cancer Res 2004; 10:184-90

3 Frey AB, Wali A, Pass H, et al. Osteopontin is linked to p65 and MMP-9 expression in pulmonary adenocarcinoma but not in malignant pleural mesothelioma. Histopathology 2007; 50:720-6

This page last revised 18.5.2007.