As HER2 receptor internalization is lower than other members of the EGFR family, only 10–20% of 111In labeled MCP-trastuzumab incubated with breast cancer cells was internalized (which was 30–50% of the radiobioconjugate bound to the cells), and most of the radiobioconjugates remained on the cell membrane. Here, EGFR is linked to breast cancer.