Detection of neuroblastoma cells during clinical follow up: advanced flow cytometry and rt-PCR for tyrosine hydroxylase using both conventional and real-time PCR

Utility of Flow Cytometry Analysis in the Detection of Nonhematologic Neoplasms: An Overview

Flow cytometry analysis has stood the test of time as a powerful tool in the assessment of hematologic neoplasms. The role of flow cytometry has expanded to evaluate various nonhematologic neoplasms encountered in body cavity malignant effusions, lymph nodes, and other body sites. This review explores the use of routine antibody panels as well as specially designed multicolor antibody panels that have been investigated by different groups and reported in the literature for evaluating nonhematologic neoplasms. In this context, the limitations, pitfalls, future directions, and promising applications of flow cytometry analysis are also discussed.

Neuroblastoma in Africa: A Survey by the Franco-African Pediatric Oncology Group

Purpose

Neuroblastoma is a sympathoadrenal lineage neural crest–derived tumor. It is the third most common childhood malignancy in the Western world. Studies from the United States show that black patients with neuroblastoma have a greater proportion of high-risk neuroblastoma with poorer prognosis compared with white patients. In Africa, there are few published data on the epidemiology and management of neuroblastoma. The primary aim of this study was to assess the diagnostic and therapeutic resources available for the management of neuroblastoma within the Franco-African Pediatric Oncology Group (GFAOP).

Methods

A survey was conducted in the pediatric oncology centers of the GFAOP. Participating GFAOP centers were Abidjan, Algiers, Bamako, Dakar, Lubumbashi, Lomé, Ouagadougou, Rabat, Tananarive Antananarivo, and Tunis. Questionnaires were sent out by e-mail to the principal investigators at each participating GFAOP center in December 2013.

Results

Ten (62%) of 16 GFAOP centers responded to the questionnaire. Neuroblastoma represented only 3% to 5% of childhood cancers in the sub-Saharan African centers, with the exception of Antananarivo, where it represented 7.5%. In contrast, in the northern African centers of Tunis, Rabat, and Algiers, neuroblastoma accounted for 30%,10%, and 7% of childhood cancer, respectively. At initial diagnosis, 50% to 80% of patients had metastatic neuroblastoma in eight of 10 centers.

Conclusion

Based on this survey, neuroblastoma seems to be less common in sub-Saharan Africa. The proportion of patients with metastatic neuroblastoma seems to be higher than reported in Western countries.

Staging and monitoring of childhood rhabdomyosarcoma with flow cytometry

Patients with metastatic rhabdomyosarcoma (RMS) have a poor prognosis. The detection of contaminating RMS cells in the bone marrow (BM) is important in clinical staging and risk assessment. The cytological examination of the BM remains the gold standard for the diagnosis of RMS, but has a limited sensitivity. In the present study, 32 BM and two cerebrospinal fluid (CSF) samples from 11 patients with suspected metastasis were analyzed by flow cytometry (FCM) with ganglioside D2 (GD2) conjugated with fluorescein isothiocyanate, cluster of differentiation (CD)90-phycoerythrin, CD45-peridinin chlorophyll protein and CD56-allophycocyanin monoclonal antibody cocktail in parallel to morphological examination at diagnosis or during treatment. Five samples (14.7%) were positive for RMS onup morphological examination. By FCM, 16 samples (47.1%) were positive for RMS. A significant difference was identified between the two methods. The four-color FCM assay successfully detected RMS cells in BM samples to a level of 0.01% (1 per 10⁴ cells). RMS cells demonstrated a phenotype with CD56⁺/CD90⁺/CD45⁻/GD2⁻ expression, which is different from the CD56⁺/CD90⁺/CD45⁻/GD2⁺ expression phenotype in neuroblastoma cells. The follow-up of four patients by FCM demonstrated that two patients became minimal residual disease-negative following two and four cycles of chemotherapy, respectively, and survived. The other two cases remained FCM-positive despite receiving four courses of chemotherapy and consequently succumbed to progressive disease. In addition, FCM analysis of the CSF samples from one patient confirmed a diagnosis of CSF metastasis with RMS. In conclusion, FCM may have a role not only in staging and monitoring the effects of therapy, but also in providing diagnostic confirmation of CSF metastasis with RMS.