Low nuclear Cdk5 expression was significantly associated with larger tumour size (χ2 = 7.858, df = 1, P = .005), higher tumour grade (χ2 = 7.630, df = 2, P = .022), mitosis (χ2 = 7.702, df = 2, P = .021), worse NPI value (χ2 = 8.386, df = 2, P = .015), ER‐negative tumours (χ2 = 6.754, df = 1, P = .009) and triple receptor‐negative tumours (χ2 = 5.927, df = 1, P = .015; Table 1). This evidence concerns the gene CDK5 and neoplasm.