ERBB2 and breast ductal adenocarcinoma: Low nuclear CYP2S1 was associated with HER2‐negative disease (χ2 = 6.396, df = 1, p = 0.011), grade 3 tumours (χ2 = 9.422, df = 2, p = 0.009), intermediate NPI (χ2 = 7.415, df = 2, p = 0.025), mitosis (χ2 = 12.492, df = 2, p = 0.002), and ductal carcinomas (χ2 = 17.161, df = 6, p = 0.007).