In situ detection of HER2:HER2 and HER2:HER3 protein-protein interactions demonstrates prognostic significance in early breast cancer..     ///    "Co-expression of HER2 and HER3 is associated with endocrine and chemotherapy resistance, driven not simply by expression but by signalling via HER2:HER3 or HER2:HER2 dimers. "    ///    PLA successfully and reproducibly detected HER2:HER2 and HER2:HER3 protein complexes in vivo.     ///    "Similarly, high levels of HER2:HER3 dimers were associated with reduced RFS (HR = 2.18, 95% CI = 1.46-3.26, P = 0.00016) and OS (HR = 2.21, 95% CI = 1.41-3.47, P = 0.001). "