Overexpression of thioredoxin-1 (TRX), which is observed in many primary human cancers, in HT-1080 fibrosarcoma cells, increased the cyclin D1, p53, and p21 expression, with cyclin D1 overexpression being particularly and directly responsible for increased cell senescence and radiosensitivity [165]. This evidence concerns the gene CDKN1A and cancer.