| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2112378 | Cancer Letters | 2015 | 7 Pages |
•S100P occurs in breast tumor tissue predominantly in a 9.2-kDa carboxyterminally truncated form.•Truncated S100P is exclusively found in the cell nucleus.•Truncated S100P can be localized in tissue sections by imaging mass spectrometry.•This novel S100P isoform is strongly prognostic for poor disease-free survival in women with node-positive breast cancer.
The calcium-binding protein S100P is overexpressed in various cancers and may contribute to the oncogenic phenotype. This study used mass spectrometry to characterize a novel 9.2-kDa C-terminally truncated form of S100P (t-S100P), and to investigate its potential prognostic value in breast cancer. Univariate analysis demonstrated the association between breast tissue t-S100P levels (n = 148) and conventional pathological markers. Across all tumor samples, high t-S100P was strongly prognostic for poor disease-free survival (P = 0.005), its efficacy confined to lymph node-positive tumors (n = 74, P = 0.007). Matrix-assisted laser desorption/ionization imaging mass spectrometry confirmed differential t-S100P abundance between breast cancer and unaffected adjacent tissue. t-S100P was exclusively located in the cell nucleus of breast cancer tissue, and full-length S100P was essentially undetectable by mass spectrometry. We conclude that t-S100P is the predominant form of S100P in breast cancer tissue and is strongly prognostic for disease-free survival in women with lymph node-positive disease.
