Morphine promoted lung metastasis 3 weeks after BC surgery in animal models.Morphine promoted postoperative recurrence, tumour proliferation and angiogenesis and reduced tumour cell apoptosis.PI3K-c-Myc signalling pathway may be related to angiogenesis promoted by morphine.Authors did not describe how morphine promoted the unexpected increased expression of TSP-1. The gene discussed is MYC; the disease is breast cancer.