Here, we used SiHa cells (HPV16-positive squamous cell carcinoma of the cervix) and showed that H2O2 and TGF-α, which are promoters of the multistep carcinogenic process [18, 19], induced c-fos/c-jun heterodimer formation in SiHa cells, whereas o-phenanthroline inhibited H2O2-induced c-fos upregulation. Here, JUN is linked to cervical squamous cell carcinoma.