This could impact on the baseline molecular profiles since it has been shown that there are significant differences in the expression of ERGs and proliferation-associated genes through the menstrual cycle.28,29 In order to reduce the effect of such changes, we used the average Ki67 or gene expression value of two pre-treatment tumour samples taken 2 weeks apart as the baseline measurement in the majority of patients. This evidence concerns the gene MKI67 and neoplasm.