Radio-labelled antibody fragments for use in the prognosis, diagnosis of cancer as well as for the prediction of cancer therapy response

A method for identifying a HER-2 positive cancer lesion in a human subject, comprising

• (a) selecting a human subject initially identified as HER-2 negative in a standard in vitro assay for identifying a HER-2 positive cancer lesion,
• (b) administering to the subject of step (a) a radiolabelled heavy chain antibody (VHH) or a functional fragment thereof, which specifically binds to HER2, wherein the amino acid sequence of said VHH or functional fragment thereof comprises the combination of a CDR1 region having SEQ ID NO:
• 1, a CDR2 region having SEQ ID NO:
• 2, and a CDR3 region having SEQ ID NO:
• 3, and
• (c) measuring using PET/CT imaging the ability of said VHH or functional fragment thereof to bind HER2 in the subject,
• wherein the VHH or a functional fragment thereof is labelled with a radioisotope selected from the group consisting of 68Ga, 18F, 64Cu, 86Y, 76Br, 82Rb, 209At, and 210At,
• wherein the subject is identified as having a HER-2 positive cancer lesion when the VHH or functional fragment thereof binds to HER2 in the subject.

A method for a performing positron emission tomography (PET) imaging study in a human subject, comprising

• (a) administering to the subject a radiolabelled heavy chain antibody (VHH) or a functional fragment thereof, which specifically binds to HER2, wherein the amino acid sequence of said VHH or functional fragment thereof comprises the combination of a CDR1 region having SEQ ID NO:
• 1, a CDR2 region having SEQ ID NO:
• 2, and a CDR3 region having SEQ ID NO:
• 3, wherein the VHH or a functional fragment thereof is labelled with a radioisotope selected from the group consisting of 68Ga, 18F, or 64Cu;
• and
• (b) measuring the ability of said VHH or functional fragment thereof to bind HER-2 positive cancer lesion in the subject.