To begin to assess the role of DARPP-32 isoforms in SCLC, we transduced DMS-53 human SCLC cells with retroviral plasmids to overexpress exogenous DARPP-32, t-DARPP, or corresponding control LacZ protein (Fig. 1c and Supplementary Fig. 1a: left panel). The gene discussed is PPP1R1B; the disease is small cell lung carcinoma.