Increased proliferation and cyclin activity are also hallmarks of cancer cells (Chai et al., 2016a), thus we aimed to characterize the expression of genes that have previously been shown to be up- or downregulated in thyroid cancer (Agrawal et al., 2014; Chai et al., 2016b; Costa et al., 2015; Wang et al., 2017). This evidence concerns the gene PCNA and cancer.