The extent to which chemotherapy may exert such an endocrine effect will depend on the type of chemotherapy, the age of the patient (known to influence the probability of chemotherapy-induced amenorrhea; Pagani et al, 1998; Goldhirsch et al, 1990), and the hormone receptor expression of the tumour (endocrine therapy will be more important in receptor-positive disease; Scottish Cancer Trials Breast Group and ICRF Breast Unit, 1993). The gene discussed is NR4A1; the disease is cancer.