Mitotic genes are rarely mutated in cancer (Cahill et al, 1999; Hernando et al, 2001), but rather affected by CNAs; for example amplification of PLK1 (Strebhardt & Ullrich, 2006; Degenhardt & Lampkin, 2010), Aurora‐A (Zhou et al, 1998b; Wang et al, 2006), survivin (Altieri, 2003), cyclin B (Malumbres & Barbacid, 2009), and NEK2 (Hayward et al, 2004). Here, PLK1 is linked to cancer.