ERBB2 and neoplasm: PolyQ-huntingtin led to ErbB2 accumulation in PyVT/HdhQ111/Q111 primary tumour cells that was inhibited when cells were treated with Trastuzumab (Fig 7A; PyVT/HdhQ111/Q111 normalized to 100% and PyVT/HdhQ111/Q111/Trastuzumab: 41% ± 14%, four independent immunoblotting experiments of at least three samples, PLSD Fisher test p < 0.05).