SDS-PAGE and western blot analysis of purified of ErbB-2-p30. (A) Lane 1, pre-adsorbtion insect cell supernatant; Lane 2, flow through; Lane 3, wash fluid; Lane 4, eluted protein containing a predominant 77 kD protein band with some faint additional bands; Western blotting revealed a single band of 77 kD (B), and a single peak was observed by mass spectrometry of the purified protein (C). The high molecular weight band in B1 is probably aggregated ErbB-2-P30. 100% of unimmunised transgenic mice and mice injected with adjuphos (D) or wild type insect cell supernatant (E & F) developed mammary tumours. A similar disease profile was observed in animals injected with ErbB-2 –P30 after the detection of tumours (G). The tumours often grew rapidly due to intratumour haemorrhage which was evident after dissection (H).