MRC1 and breast cancer: The radiolabeled mannosylated dextran derivative 99mTc-Tilmanocept (Lymphoseek®, 23 amino acids, 55 mannose moieties, and 8 diethylenetriaminepentaacetic acid [DTPA] chelators per dextran molecule), which binds to macrophage mannose receptor CD206, was approved by the FDA in 2014 for lymphatic mapping and lymph node localization in breast cancer, melanoma, squamous cell carcinoma, and other solid tumors [19].