Prognostic significance of cyclin A and B1 in pediatric embryonal tumors.

Embryonal tumors constitute the most common malignant brain tumor group in children. Although patient prognosis has been substantially improved over recent decades, identification of prognostic markers would be of obvious significance. In the present study we evaluated the prognostic significance of cyclin A and B1 in correlation with Ki-67 index in pediatric embryonal tumors. We retrospectively evaluated 53 children with embryonic tumors who were treated surgically in our institute. All patients had regular follow-up examinations. The streptavidin-biotin-horseradish peroxidase (HRP) method was performed on paraffin sections for detection of Ki-67/MIB-1, and cyclin A and B1. There were 42 cases of medulloblastoma (MB), 9 cases of atypical teratoid/rhabdoid tumor (AT/RT), and 2 cases of supratentorial primitive neuroectodermal tumor (PNET). In MB patients, Ki-67 index >50% was associated with worse survival (P = 0.003). Cyclin A index >40% was associated with significantly poorer survival (P = 0.023). Patients with cyclin B1 index >15% exhibited a trend towards poorer survival (P = 0.068). On multivariate analysis, only Ki-67 index was identified as a factor with independent prognostic power. In AT/RT and PNET, there was high expression of Ki-67 and variable expression of cyclin A and B1. Apart from Ki-67 index, cyclin A may have a prognostic role. Study of the above indices at diagnosis could alter or intensify treatment methods, so as to improve disease outcome. There is obviously a need for future studies with larger number of patients to confirm our preliminary observations.