DICER1 and breast cancer: Furthermore, analysis of Dicer copy number using data from Cancer Genome Project at the Sanger Institute revealed hemizygous deletions of DICER1 in 27% (207/761) of tumours derived from tissues of diverse origins such as central nervous system, lung, pancreas, soft tissues, breast and bone [12] and hemizygous deletion of Dicer was also observed in approximately 37% of breast cancers [12].