ERBB2 and cancer: HER2 is involved in the regulationof several signaling pathways that lead to an increase in cell proliferationin several types of cancer.33,34 Because HER2 is knownto localize in clusters on the membrane,3,35,36 one therapeutic strategy is the disruption of thisorganization.37,38 To study this dynamic nanoscaleprocess, the TPE-based probe is conjugated to an antibody specificto the extracellular domain of HER2.