To determine whether one or more of the HPV18 oncoproteins was responsible for STAT3 activation, the levels of STAT3 phosphorylation were measured by western blot analysis of C33a (an HPV-negative cervical carcinoma cell line) cells expressing individual GFP-tagged HPV18 oncoproteins (Fig 2A). The gene discussed is STAT3; the disease is cervical carcinoma.