PCNA and neoplasm: Given that miR-30a-5p overexpression inhibited tumour growth in our in vitro studies, we subsequently explored the effects of miR-30a-5p on tumour growth in vivo by IHC, the results of which showed that tumour growth and tumour weight were significantly decreased in the miR-30a-5p-overexpression group compared with the negative control group (Fig. 4a and Supplementary Figure S1e) and that Ki-67 and PCNA expression levels in the miR-30a-5p-overexpression group were lower than those in the negative control group (Fig. 4b).