Representative IHC findings for FilGAP, FLNa, integrin β2, ECT2, Rac1, and Ki‐67 in astrocytomas are illustrated in Figure 1A. Immunoreaction for FilGAP was mainly observed in cytoplasmic and/or nuclear compartments of astrocytoma cells. The gene discussed is RAC1; the disease is astrocytoma (excluding glioblastoma).