PCNA and cervical carcinoma: Withaferin-A-mediated G2/M phase cell cycle arrest in cervical cancer (Caski) cells was associated with decreased expression of cyclin B1, p34 (Cdc2) and proliferating cell nuclear antigen (PCNA), and diminished phosphorylation of STAT3 at tyrosine 705 and serine 727 residues [22].