In this study, we identified a potent candidate biomarker, Polo-like kinase 2 (PLK2, chromosome 5q11.2), and a possible therapeutic target PLK1, that may not only help stratify patients with TNBC for treatment, but also benefit for patients with other cancers that exhibit chromosome 5q loss across the PLK2 region (9, 10). This evidence concerns the gene PLK2 and cancer.