Histological indicators of prognosis in glioblastomas: retinoblastoma protein expression and oligodendroglial differentiation indicate improved survival.

AIM: To assess the potential prognostic significance of a range of molecular and morphological parameters in glioblastomas that can be applied in the setting of a routine diagnostic neuropathology laboratory. METHODS AND
RESULTS: A consecutive series of 107 adult glioblastomas were studied. Retinoblastoma and deleted-in-colon cancer (DCC) protein expression were assessed using immunocytochemistry and chromosome 10 loss by in-situ hybridization. Loss of retinoblastoma expression was associated with a worse outcome, which appeared to be independent of age. There was no significant association between chromosome 10 loss or DCC protein expression and survival. Survival was significantly increased in the 5% of patients whose tumours had focal morphological features suggesting oligodendroglial differentiation.
CONCLUSIONS: Glioblastomas containing areas of oligodendroglial differentiation or showing widespread immunocytochemical expression of retinoblastoma protein have a better prognosis than those without these features.