To further validate the association of patients’ survival with SLC7A3, SLC7A5, and SLC7A11 expression levels, multivariate analyses were applied between patients’ survival and the mortality-associated features, including patients’ age, tumor size, cancer stage, thyroiditis, and SLC7A3, SLC7A5, and SLC7A11 expression levels. This evidence concerns the gene SLC7A3 and thyroiditis.