B114
DNA ploidy and proliferative activity in common round cell tumours in children and their value as prognostic indicators
Amira Raafat, Sonia Mahmoud, Shadia El Gerzawi, Moustafa El Serafi
National Cancer Institute, Cairo, Egypt
Background and Aim
Traditional clinico-pathologic criteria are often inadequate to accurately
identify, children with small round cell tumours who will have poor response to
therapy. Abnormal cellular DNA content (aneuploidy), has been linked to the
rate of cell proliferation, and ultimately to prognosis. Flowcytometry (FCM),
is a relatively rapid and precise technique, allowing quantitative detection
of DNA content and measurement of S phase fraction (SPF), which can be
used to classify cases into prognostically different subgroups. This may
help in choosing the suitable chemotherapeutic regimens.
The aim of this study was to evaluate the ploidy status and cells in SPF of
common round cell tumours of Egyptian children, using FCM, correlating
these parameters with the clinical and biological features and showing their
effect on treatment and survival.
Method
The study included 50 children with round cell tumours, presenting to the National Cancer Institute (NCI), Cairo University. Only patients with complete follow up, full data were included in the study. Patients in each tumour type received the same treatment, and response to treatment was assessed according to the World Health Organization (WHO) criteria. Nuclear suspension was prepared for each sample, stained with propidium iodide. Measurements were performed using a FACScan flowcytometer and 10.000 cells were acquired for each sample. Results presented as frequency distribution histograms.
Results
In 20 neuroblastoma cases, DNA ploidy and index correlated significantly with progression free survival (PFS) and overall survival (OS). Diploid tumours fare worse than aneuploid ones. Response to treatment significantly correlated to ploidy (p = 0.019) and status of patient (p = 0.006). SPF correlated significantly to ploidy (p = 0.03) and to DNA index. In 15 rhabdomyosarcoma cases, only ploidy significantly correlated with PFS and to OS. DNA index significantly correlated with OS. In 15 Non Hodgkin's lymphoma (NHL) cases, only SPF correlated significantly to PFS.
Conclusion
DNA analysis by FCM is a valuable prognostic factor of great benefit in treatment of neuroblastoma, and can be used to confirm biological entity of tumours. Ploidy is prognostic in rhabdomyosarcoma , identifying high risk patients for treatment failure even with favorable standard criteria. In NHL, SPF may be a useful prognostic marker, only to response to treatment but not to survival.
