However, recent studies on psoralen derivative I incapable of inducing ICL formation (Fig. 1c) revealed the evidence that the anti-cancer effects of PUVA can also be mediated through a DNA-independent mechanism, involving the direct binding of psoralen with the catalytic autokinase domain of human epidermal growth factor receptor 2 (HER2; also known as erythroblastic oncogene B or ErbB2)11. The gene discussed is ERBB2; the disease is cancer.