In order to evaluate the binding specificity of 68Ga-labeled VHH to CD70 in a cell assay, we have first profiled CD70 expression in different cancer cell lines by flow cytometric analysis, using either a fluorescently labeled anti-CD70 VHH (same sequence as NOTA-anti-CD70 VHH) or a PE anti-human CD70 antibody. The gene discussed is CD70; the disease is cancer.