TG and central nervous system cancer: In contrast, we firstly found thyroid hormones decreasing and NTIS prevalence increasing during chemotherapy in breast cancer patients, however, growth of breast cancer cells is regulated by thyroid hormones [34], thyroid hormones are considered to be the growth factor for glioma and thyroid cancer [35], the absence of thyroid hormones in cells could provoke a proliferation arrest in G0-G1 [36] or weak mitochondrial activity [12], which makes tumor cells insensitive to chemotherapy.