Furthermore, given the fact the ligand-less ErbB2 typically requires another ErbB receptor as a dimerization partner for effective signaling, and that in cancer biology, ErbB2 is known to be the preferred heterodimerization partner for EGFR [10], [30], we hypothesized that activation of ErbB2 might also involve heterodimerization with EGFR. Here, EGFR is linked to cancer.