SOCS1 and in situ carcinoma: It is possible that endogenous or exogenous prolactin could elevate CIS transcripts in these lines, but the lack of correlation between CIS transcript levels and expression of other SOCS transcripts argues against this, given that prolactin is able to induce SOCS-1,-3 and CIS transcripts in mammary tisue (Tam et al, 2001).