H2AX and melanoma: Using the γ-H2AX assay, we previously have shown that hyperthermia enhances production of DSBs or results in the inhibition of DSB repair in cultured U-1 melanoma cells treated with FeSO4-PyED; thus, potentiation by hyperthermia of cell death induced by FeSO4-PyED is likely mediated via the creation of more initial DSBs or through alteration of the DNA damage repair response [32].