COPS5 and neoplasm: Since (1) the tamoxifen-refractory tumour samples used for IHC were biopsied/autopsied from patients who had been treated with tamoxifen for at least 5 months to >10 years; and (2) short-term treatment of MCF7 cells with tamoxifen in vitro or in vivo did not alter the COPS5 protein expression (Supplementary Fig. 16), the elevated COPS5 expression is probably due to drug resistance-associated selection (genomic amplification) rather than acute induction by tamoxifen.