Treatment of VHHs conjugated with radionuclides in in vivo studies resulted in high and specific tumor uptake in multiple myeloma (38), HER2+ breast cancer (103, 105), ovarian cancer (103), TS/A mammary carcinoma (102), multiple myeloma (106)and non-Hodgkin lymphoma (104). This evidence concerns the gene ERBB2 and plasma cell myeloma.