PCNA and hemorrhagic stroke: Interestingly, it has been reported that the number of apoptotic cells positively correlated with Wnt3a and β-catenin mRNA expression, whereas the proliferating cell nuclear antigen (PCNA)+ cells negatively correlated with Wnt3a and β-catenin mRNAs during the early brain injury phase and the second phase of hemorrhagic stroke (Zhou L. et al., 2014).