PCNA and neoplasm: Furthermore, tumour tissues originating from PANC‐1 cells treated with exosomes had higher KI67 and PCNA expression than those originating from control cells, whereas KI67 and PCNA expression was reduced in tumour tissues derived from PANC‐1 cells with tRF‐19‐PNR8YPJZ‐knockdown (Figure 5D).