CCNA2 and breast carcinoma: Several studies have shown an association between overexpression of cyclin A and poor survival in breast cancer (Bukholm et al, 2003a, 2003b, 2001; Michalides et al, 2002; Michels et al, 2003), whereas one study did not confirm it (Kuhling et al, 2003; Rudolph et al, 2003).