Strikingly, treatment with metformin might reduce tumor growth, mainly by inducing the expression of a set of genes FOSB, EGR1, ZFP36, GPR183, ATF3, and NR4A1 which are involved in DNA-binding transcriptional activation, response to hormones and the Dcp1-Dcp2 mRNA-decapping complex. The gene discussed is ATF3; the disease is neoplasm.