CDKN1B and breast carcinoma: Using the breast cancer cell line MDA‐MB‐468, the fibrosarcoma cell line HT‐1080, and the renal cancer cell line Caki‐1, we showed that p27 was predominantly localized to the cytoplasm of the three cell lines (Fig. 6A; Kim et al., 2009; Viglietto et al., 2002).