TG and glioblastoma: Thus, patients with low serum levels of the hormone L-triiodothyronine (T3) exhibit a greater predisposition to strokes (Jiang et al., 2017), and there also appears to be a correlation between the levels of thyroid hormones and certain types of astrocytomas (Ding et al., 2013; Xiong et al., 2018), such as glioblastoma multiforme (GBM).