Fibroblast growth factor receptor (FGFR) 4 possesses high affinity to acidic and basic fibroblast growth factors (FGFs). The authors focused on FGFR 4 expression in astrocytoma because the FGF expression increases as the tumor malignancy progresses. Forty-one astrocytoma specimens were examined by immunohistochemistry and polymerase chain reaction-Southern blot. FGFR 4 was negative in all seven Grade II astrocytomas by immunohistochemistry, while positive in four among 15 Grade III and in 13 among 19 Grade IV astrocytomas. The median survival time of Grade III astrocytoma patients was 22.3 months in FGFR 4 negative group and 14.5 months in positive group (p 0.05, not significant). However, FGFR 4 mRNA was detected in all specimens suggesting activated translation system of FGFR 4 in progression of the tumor malignancy. Histologically diagnosed Grade III astrocytoma patients can be divided into two groups; one with median survival time close to those with Grade II astrocytoma patients, and the other similar to that of glioblastoma patients. The authors concluded that FGFR 4 must be an important factor which predicts short survival Grade III astrocytoma patients, who require strict adjuvant therapy in accordance with glioblastoma.