Immunohistochemistry for CCNB1‐positive expression rate
The PC and normal pancreas tissues were fixed with formaldehyde, embedded in paraffin, and cut into 4‐μm serial sections. The sections were baked in a 60℃ incubator for 1 hr, conventionally dewaxed with xylene, dehydrated with gradient ethanol and then immersed in 3% H2O2 for 10 min. The sections were subsequently washed with distilled water, placed at a high pressure for 90 s for antigen retrieval, cooled at room temperature and washed with phosphate‐buffered saline (PBS). After that, the sections were further blocked with 5% bovine serum albumin and incubated at 37℃ for 30 min. The sections were added with diluted primary antibody rabbit anti‐human CCNB1 (1:500, EPR17060; Abcam Inc., Cambridge, MA) for incubation at 4℃ overnight, followed by PBS washing. Then, the sections were added with the diluted biotin‐labeled immunoglobulin G (IgG) secondary antibody (1:100; HY90046; Shanghai HengYuan Biological Technology Co. Ltd., Shanghai, China) for incubation at 37℃ for 30 min, followed by PBS washing.
