COP1 and neoplasm: In addition, CSN6, COP1, FOXO4, PHGDH, PSAT1, and SHMT2 demonstrated a significant correlation in staining intensity in five pairs of primary tumor/normal tissue samples as expected (Figure 8C), i.e., high CSN6 expressing tumors have lower levels of FOXO4 with concurrent high expression of COP1, PHGDH, PSAT1, and SHMT2.