To investigate whether these tumors also express Lrig1, we performed in situ hybridization (Fig. 1a) and observed that the PDGFB-induced gliomas as well as normal mouse brain tissue expressed Lrig1. Quantification of the in situ hybridization signals for Lrig1 from three normal brains, three grade II–III tumors, and three grade IV tumors showed pronounced intra-group variability and a lack of a consistent difference among the groups (Fig. 1b). The gene discussed is PDGFB; the disease is glioma.