To determine the biological consequences of miR-154-3p and miR-487-3p in thyroid cancer cell lines K-1 and B-CPAP, pre-miR-154-3p, pre-miR-487-3p or pre-miR-154-3p/487-3p was transfected into K-1 and B-CPAP cells, and cell proliferation and apoptosis were evaluated using CCK8 and Annexin V-FITC double staining, respectively. The gene discussed is CPAP; the disease is thyroid cancer.