engleski

Cytogenetic Characteristics of Childhood Lymphoma

BACKGROUND Lymphomas are relatively frequent form of malignant disease in children. The disease is characterized by marked biologic heterogeneity. The heterogeneity of malignant lymphomas has been confirmed by morphologic, immunologic and cytogenetic analyses. In the past 20 years cytogenetic studies revealed different chromosomal abnormalities specific for lymphomas. Investigations carried out so far have mostly dealt with population of adult patients, whereas studies in children with lymphomas are still rare. OBJECTIVES The aim of this investigation was to define the frequency and types of clonal chromosomal abnormalities of malignant cells in our group of childhood non-Hodgkin's lymphoma. METHODS Our investigation included 16 children, 4 girls and 12 boys aged from 9 months to 15 years. Using cytological (FNA biopsy, exfoliative or imprint method) and histopathological methods of deep paediatric lesion, ascites, pleural drain or intraoperative material we diagnosed lymphoma. Cytogenetic analysis of malignant cells was carried out at the time diagnosis was made, before initiating therapy. Slides were obtained from direct or short -term culture of lymph node and/or bone marrow cells. Chromosome identification was carried out using the G-banding method. Chromosomal abnormalities were described according to the International System for Human Cytogenetic Nomenclature (1991). RESULTS The results of cytological and histopathological diagnosis were compared. Correlation of the results was markedly high. Cytogenetic analysis revealed clonal chromosomal abnormalities in 11 (68, 7%) out of 16 children. Chromosome instability and evidence of clonal evolution were observed in 3 patients. Pseudodiploid clone was observed in 4, hyperdiploid in 5 and hypotriploid in 2 out of 11 children with clonal chromosomal aberrations. This investigation revealed complex numerical and structural aberrations. The gains of some chromosome types were nonrandom and frequently affected chromosomes were 11, 14, 21 and X. Involvement of particular chromosome type in structural abnormalities was nonrandom too. Chromosome No.1 and No. 14 were abnormal in 5 and 4 cases respectively. CONCLUSION This investigation confirms variability of clonal chromosomal aberrations and cytogenetic heterogeneity of childhood non-Hodgkin lymphomas. Additional investigations are however, necessary to define more precisely the frequency and types of aberrations, and biological role of chromosomal regions in the development of NHL.

Children; lymphoma; cytogenetics

nije evidentirano