PRDX4 and thyroid gland undifferentiated (anaplastic) carcinoma: PRDX1, PRDX2, and PRDX3 mRNA synthesis decreased in papillary and anaplastic thyroid cancers (Fig. 1p–r), PRDX4 mRNA expression was moderately increased in anaplastic thyroid cancer tissues (Fig. 1s), and PRDX6 expression status was at similar levels in normal thyroid and thyroid cancers (Fig. 1t).