The immunohistochemical staining showed that compared with APCmin/+ mice, the level of Ki67+, PCNA in APCmin/++SR‐B1−/+ mice was significantly reduced, while the level of CASP3 was significantly increased (p < 0.01), which indicated that SR‐B1 knockdown inhibits the growth of tumor cells. The gene discussed is MKI67; the disease is neoplasm.