RAC1 and retinoblastoma: The stronger association of TIAM1 than RAC1 with NE gene expression suggests that in NE SCLC increased expression of select GEFs may lead to increased RAC activity independent of total RAC1 levels, consistent with previous findings in retinoblastoma (Adithi et al., 2006) and nodular melanoma (Dalton et al., 2013).