RAC1 and small cell lung carcinoma: Because TIAM1 is a RAC-specific GEF (Michiels et al., 1995), we hypothesized that treatment of SCLC cell lines with NSC-23766, a compound that inhibits RAC1 activation by RAC GEFs including TIAM1 (Gao et al., 2004), might also reduce cell viability.