Functional analysis indicated that SMC1A knockdown by small interfering RNA (siRNA) mediated the significant inhibition of cell proliferation; induced cell cycle arrest and apoptosis via the suppression of CDK4, PCNA and PARP; and blocked the activation of the Erk1/2 and Akt cascades in CRC cells. The gene discussed is MAPK3; the disease is colorectal carcinoma.