LRIG1 and cancer: Next, we probed the role LRIG1 played in anti-cancer activity of ISL, we showed that ISL induced cell apoptosis was reversed when LRIG1 was knocked down, the expression level of pro-apoptotic genes(C-PARP, Bax, C-caspase-3) was enhanced (Fig. 6f, g and Additional file 4: Figure S3E, F, G).