CYP2C8 and neoplasm: The increasing number of CYP2C8*3/*1/*2/*1 alleles was associated with shorter disease-free survival in 297 ER-positive patients with invasive tumours who had received tamoxifen prior to the last follow-up or event (log rank 6.36; 1 df; P=0.012), HR 2.54 (95% CI 1.11–5.79; P=0.027), adjusted for age, tumour size, axillary lymph node status, PR status, histological grade, and other haplotypes.