MMP9 and small cell lung carcinoma: Administration of TQ (10, 20, 40 μmol/L) on a SCLC cell line also inhibited cell proliferation, migration, proliferating cell nuclear antigen (PCNA), cyclin D1, MMP2 and MMP9 mRNA levels, activated the extracellular signal‐regulated kinase 1/2) ERK1/2 (pathway and inhibited cell cycle via P16 expression and the gelatinase activities of MMP2 and MMP9.55