RB1 and small cell lung carcinoma: However, experiments conducted in Trp53F/F;Rb1F/F mice by Sutherland et al. (2011) showed that cell type-restricted adenoviral vectors carrying Cre under the promoter of the SPC gene (Ad5-SPC-Cre), enabling deletion of Rb1 and Trp53 tumor suppressor genes specifically in AT2 cells, was also able to induce SCLC, although much less efficiently as compared with Ad5-CGRP-Cre that directed Cre expression to CGRP+ NE cells.