DHFR and neoplasm: They are both overexpressed in tumor cells, and potential molecular target of chemotherapeutic drugs, such as antifolates for DHFR (e.g., methotrexate) (Raimondi et al., 2019), and alkylating agents selectively modifying the selenocysteine (Sec) residue for TrxR (Urig and Becker, 2006).