The effects of testosterone and IGF-1 mainly contributed to the transitions from event-free to in-situ breast cancer (Testosterone: HR for the highest quartile = 1.31, 95 % CI = 1.12–1.53; IGF-1: HR for the highest quartile = 1.17, 95 % CI = 1.00–1.38), and the transitions from event-free to invasive breast cancer (Testosterone: HR for the highest quartile = 1.46, 95 % CI = 1.37–1.56; IGF-1: HR for the highest quartile = 1.17, 95 % CI = 1.10–1.24). The gene discussed is IGF1; the disease is breast carcinoma in situ.