SNAI2 and neoplasm: Mechanisms other than genomic loss of the SNAI2 locus may be relevant for hormone responsiveness as at least one patient had a good partial tumor response despite having only a very low level of single-copy loss or deep deletion of SNAI2. For instance, SNAI2 expression is known to be regulated by epigenetic modification54 and microRNAs,55 two mechanisms we have not explored in this study.