In contrast to NC-sdAb-Cy5.5 fluorescence, which could not be detected in either tumour or healthy brain tissue sections (data not shown), anti-IGFBP7 sdAb-Cy5.5 fluorescence (red) was selectively localised in brain tumour vessels stained with injected lectin (Figure 4B), but not in healthy brain tissue vessels (Figure 4C). The gene discussed is IGFBP7; the disease is brain neoplasm.