The key finding of this report is that in not only glioma cells but also certain types of breast cancer cells, overexpression of p42 permits access of HSP70/CHIP in the vicinity of p85 thus facilitating its proteasomal degradation, as evidenced by the observation that cells expressing p42 displayed a much lower intensity of p85 fluorescence compared with vector or p48-expressing cells. The gene discussed is STUB1; the disease is breast carcinoma.