Towards detecting the HER-2 receptor and metabolic changes induced by HER-2-targeted therapies using medical imaging.
HER-2/neu (a receptor for human epidermal growth factor) is involved in cell survival, proliferation, angiogenesis and invasiveness. It is overexpressed in about 25% of breast cancers. Overexpression of HER-2 is associated with response to the anti-HER-2 antibody trastuzumab (herceptin). However, HER-2 expression can be heterogeneous within the primary tumour and can also exhibit discordant expression between a primary tumour and its metastases, bringing into question the practice of HER-2 screening to determine whether a patient is a candidate for trastuzumab using material obtained only from the primary tumour. Medical imaging modalities using HER-2-targeted tracers (or contrast agents) facilitate a global approach to the determination of HER-2 expression across all detectable tumour lesions, and could provide a more reliable indication of the patient's likely response to trastuzumab treatment. Here, I review the development and pre-clinical (and occasional clinical) assessment of HER-2-targeted tracers. I discuss studies in which established imaging tracers, such as (11)C-choline, have been used to determine response to trastuzumab in a range of medical imaging modalities, including positron emission tomography (PET), single photon emission tomography (SPECT), MRI and optical imaging.
Smith
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School of Medical Sciences, Biomedical Physics Building, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK. t.smith@abdn.ac.uk
D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis / Q000378:metabolism*; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy / Q000378:metabolism*; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D002794:Choline / Q000493:pharmacokinetics; D005260:Female; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D006801:Humans; D007205:Indium Radioisotopes / Q000493:pharmacokinetics; D008279:Magnetic Resonance Imaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D000068878:Trastuzumab
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D002250:Carbon Radioisotopes; D002794:Choline; D005456:Fluorescent Dyes; D007205:Indium Radioisotopes; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab