GFAP and neoplasm: When MRI images at PID8 (Figure 4A) were compared with RNAscope images at PID9, the hyperintense signal on the MRI (Figure 4C, aligned in red) extended beyond the area of dense tumor cells (Figure 4D, aligned in blue) and included a large part of a GFAP+ astrogliotic rim around the dense tumor core as well (Figure 4D, aligned in red).