Transcription factors Sp1 and Ets were previously associated with basal activity of heparanase promoter 39–41, while early growth response 1 (EGR1) transcription factor 42 and oestrogen receptor 43 were implicated in inducible transcription of the heparanase gene in prostate and breast carcinomas (respectively). Here, HPSE is linked to breast carcinoma.