Breast cancer metastases

We have analysed a unique tumour set of fourteen primary breast cancer tumours with matched synchronous axillary lymph node metastases and a set of nine primary tumours with, later developed, matched distant metastases spread to different sites in the body. The aim was to further understand the molecular changes during the spreading and identify differentially regulated proteins that may be novel biomarkers or treatment targets. We analysed the changes in glycoprotein expression since protein glycosylation is predominant in both membrane proteins and secreted proteins and these proteins are often important for cancer transformation. This may also allow affinity capture enabling selected reaction monitoring of these biomarkers in blood. Glycopeptide capture was used in this study to selectively isolate and quantify N-linked glycopeptides from tumours mixtures and the captured glycopeptides were subjected to label-free quantitative tandem mass spectrometry analysis. Differentially expressed proteins between primary tumours and matched lymph node metastasis and distant metastasis were identified. Two of the top hits, ATPIF1 and tubulin β-chain were validated to be differentially regulated with immunohistochemistry.