CDKN1B and breast cancer: Group B3 was characterized by expressions of ACTA2 and TAGLN, and it only consisted of few cells with high expressions of proliferative markers CDKN1B and BCL2. In particular, the number of interface-derived cells was higher than that of tumor or normal-derived cells in group B1, B2 and B3, suggesting a unique property of the interface zone of breast tissues in breast cancer patients.