PCNA and breast cancer: In this regard, Qu and coworkers reported a biodegradable hybrid hydrogel comprised of gold nanorods (GNR) incorporated Methoxylpoly (ethylene glycol)-poly(ε-caprolactone)-acryloyl chloride (PECA) /glycidyl methacrylated chitooligosaccharide (COS-GMA)/N -isopropylacrylamide (NIPAm)/acrylamide (AAm) (PCNA) hydrogel (PCNA-GNR hydrogel) for the post-surgery treatment of breast cancer.