DLL1 and cancer: We first carried out an RT-PCR analysis for the transcripts of Notch1, Notch2, Notch3, Notch4, Jagged1, Jagged2, Delta-like1(Dll1), Delta-like3 (Dll3), and Delta-like4 (Dll4) from several immortalized and transformed breast cell lines (Additional file 1: Table 1) We were able to detect transcripts of all members of the Notch family, except for Dll3 in diverse immortalized and cancer cell lines.