Results showed that compared with the NC miRNA + empty vector group, KRAS could promote the proliferation of osteosarcoma cells (NC miRNA + KRAS vector, p = 0.0021, t = 7.114) and hsa-miR-557 could inhibit the proliferation of osteosarcoma cells (hsa-miR-557 + empty vector, p = 0.0007, t = 9.457), while the transfection of the KRAS vector could alleviate the inhibition effect of hsa-miR-557 (hsa-miR-557 + KRAS vector vs hsa-miR-557 + empty vector, p = 0.0038, t = 6.039) (Figures 5A,B). Here, KRAS is linked to osteosarcoma.