Petosemtamab uniquely targets both LGR5+ stem-cell-like cells and the remaining LGR5- cells within a tumor through three distinct mechanisms: inhibition of EGF ligand binding and EGFR signaling, similar to other EGFR antibodies such as cetuximab; degradation of EGFR specifically in LGR5+ cells; and targeting LGR5+ and EGFR+ cells for immune-mediated destruction through ADCP and enhanced ADCC. Here, LGR5 is linked to neoplasm.