Pineal parenchymal tumours: II. On the aggressive behaviour of pineoblastoma in patients with an inherited mutation of the RB1 gene.

This report relates to a retrospective analysis of two non-randomised cohorts of patients with pineoblastoma, with some differences in presenting features and treatment characteristics. We have identified a large difference in survival depending on the possession or otherwise of the mutated RB (retinoblastoma) gene in the genome/karyotype. Eight children with familial retinoblastoma (non-metastatic at presentation) developed pineoblastoma and were treated by chemotherapy and radiotherapy. The survival of these patients was compared with the survival of nine non-metastatic sporadic cases of pineoblastoma similarly staged and treated. One out of eight children having the RB mutation in the genome survived compared with seven out of nine in the group with sporadic pineoblastoma (P = 0.002). It is suggested that the inheritance of the mutated retinoblastoma gene is not only causal in the generation of this tumour type but, in a way that is yet to be defined, renders such tumours more aggressive or less responsive to therapy. With the current interest in the role of RB mutations in other cancers (where the prognostic import of single genes is less easily identified), this observation may have wider relevance.