Conjugated SOR peptides may be of utility for detecting (via MRI contrast agent) tumors and delivering diagnostic or therapeutic payloads (e.g. chemotherapeutic substances) specifically and directly to the TRPV6-rich tumor of ovarian and potentially others such as breast, thyroid, prostate and colon as well as certain leukemia's and lymphomas (Fig. S9). The gene discussed is TRPV6; the disease is neoplasm.