Molecular markers in breast cancer: new tools in imaging and prognosis

Breast cancer is the most frequently diagnosed cancer in women. Although breast cancer is mainly diagnosed by mammography, other imaging modalities (e.g. MRI, PET) are increasingly used. The most recent developments in the field of molecular imaging comprise the application of near-infrared fluorescent labeled (NIRF) tracers for detection of breast cancer. Thus far, only a few molecular imaging tracers have been taken to the clinic of which most are suitable for PET. My thesis describes the expression of markers in breast cancer that are potentially suitable for molecular imaging strategies. In contrast to aggressive breast cancers, we found that detection of lobular and low grade breast cancers by molecular imaging strategies might be limited by infrequent expression of tumor-specific markers. Markers with expression in normal breast epithelium are more frequently present in lobular breast cancer, these markers might be necessary for imaging of lobular breast cancer. Furthermore, we found that markers in female breast cancer are differentially expressed in male breast cancer. In this thesis we also explored whether identified markers for imaging of breast cancer could be useful for image-guide surgery of ductal carcinoma in situ (DCIS) using molecular imaging, and whether expression differs between DCIS and adjacent invasive breast cancer. We found that expression of markers in pre-invasive stages of breast cancer and adjacent breast cancer is highly similar. This underlines the potential for detection of pre-invasive stages of breast cancer using molecular imaging. Finally, we tested in preclinical breast cancer models the suitability of molecular imaging for detection of DCIS.