When DDR1 knocked down HepG2 cells were treated with or without C1q, knockdown was found to significantly attenuate C1q-induced migration and invasion, indicating C1q activates DDR1 to regulate cancer progression, which is in-line with previous reports that DDR1 plays important roles in the progression and metastasis of breast and lung cancer cells32. The gene discussed is DDR1; the disease is lung cancer.