PCNA and neoplasm: Kaempferol is a flavonoid with anti-tumor and antioxidant damage functions, which not only participates in a wide range of bioprocesses, such as cell proliferation [18], apoptosis [19], cell cycle [19] and autophagy [20], but also inhibits proliferation of human renal carcinoma 786-O cells, reduces the expression of PCNA and VCAM-1, and induces 786-O cells to block in the S-phase and G2/M-phase [21].