Osteopontin expression in a group of lymph node negative breast cancer patients

Role of osteopontin in tumour progression

“…There also is some suggestion that OPN from different sources may have different prognostic value. As noted above, Tuck et al (1998) found that OPN immunopositivity within breast tumour cells was associated with poor patient survival, whereas OPN in infiltrating host cells in the tumours was common and not associated with survival. It should be noted that OPN is not specific to tumours, but is expressed by a number of other tissues, under normal or pathological conditions, and this must be considered in any studies assessing the utility of OPN as a marker of prognosis in cancer.…”

“…In a series of 25 lung tumour specimens, OPN protein and RNA were elevated in tumour tissue, relative to normal lung tissue, and OPN immunopositivity was statistically significantly associated with patient survival . In the study described above by Tuck et al (1998), examining tumours from lymph nodenegative breast cancer patients, OPN protein detected specifically in the tumour cells in breast tumours correlated significantly with disease free-and overall survival in these patients. Consistent with this finding is a case report of bilateral mammary carcinomas , in which OPN tumour cell immunopositivity, as well as p53 immunopositivity, were associated with the tumour that recurred locally and progressed to form metastases in the liver and bone.…”

“…In this study, OPN RNA was found to be produced primarily by tumour-associated macrophages rather than tumour cells themselves. However, Tuck et al (1998), examined a series of tumours from 154 lymph node-negative breast cancer patients. Osteopontin RNA and protein were detected in both tumour cells and infiltrating inflammatory cells: host immune cells were positive for OPN protein in 70% of tumours, while only 26% of tumours were positive for OPN immunostaining in the breast tumour cells themselves.…”

“…Finally, OPN immunopositivity in a group of 333 breast cancer patients demonstrated a negative correlation with survival (Rudland et al, 2002). Given the common finding of OPN in nontumour (infiltrating) cells, reported by Tuck et al (1998), it may be that OPN protein detection, when limited to quantification from only the tumour cells, may provide more useful predictive information than RNA levels quantified from tumour tissue, at least for breast cancer.…”

Pre- and post-translational regulation of osteopontin in cancer

“…OPN produced by other cells in the tumour microenvironment, such as macrophages and stromal cells, has been seen in a number of different cancer types as well (Reinholt et al 1990). For example, in a cohort of lymph node negative breast cancer patients, OPN mRNA and protein were detected in both tumour cells and tumour infiltrating inflammatory cells (Tuck et al 1998). Tumour cells and macrophages were determined to be OPN-positive in a sample of pulmonary artery sarcomas, where OPN had also been incorporated into the extracellular matrix (ECM) (Gaumann et al 2001) and Chang et al (2008) found similar results in cutaneous squamous cell carcinoma, as most cases showed the presence of OPN in both cancer cells and in ECM adjacent to the tumour.…”