Abstract
Recurrent cytogenetic abnormalities are the hallmark of all malignant tumors. Classification of malignancies depends on the location of the chromosomic disruption/deletion, which relates to prognosis of the disease and therapeutic choices. Molecular genetics and cytogenetics techniques are used to identify oncogenes localized near the chromosomic breakpoints, and oncogenes activation seem to be dependent on translocation mechanism. Recurrent atypical cytogenetic abnormalities of chromosome 6p have been reported in a few cases of translocations implicated in Retinoblastoma. The translocation der t(4;6)(p15;p21.2) was studied in the Y79 cell line established from the primary tumor (right eye) of a 2-year-old Caucasian girl in 1971. To determine the site of the breakpoint on 6p, yeast artificial chromosome (YAC) clones from p21 to p22 bands were used. The breakpoint has been localised by FISH on 6p21.3 and the TNF-alpha gene has been shown to be involved in this rearrangement. TNF-alpha is a cytokine, a specialized hormone-like protein that can influence cellular development and function. Flow cytometric analysis has been shown to be useful to measure the expression of both cytoplasmic and cell surface proteins in retinoblastoma cells. To measure the expression of TNF-alpha gene in retinoblastoma cells, flow cytometnc analysis and cytospins were performed using an anti-TNF-alpha antibody. This study has shown an enhancement of the expression of TNF-alpha gene in Y79 cells. Further cloning, sequencing and characterisation of the gene(s) involved in this rearrangement from patient samples with this reccurent breakpoint will allow us to study the possible consequences of disruption/deletion of this gene in the development or progression into low to high grade disease.
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Imbert, I., Coignet, L. & Pellestor, F. Molecular analysis of chromosome 6p rearrangement in retinoblastoma. Genet Med 2, 105 (2000). https://doi.org/10.1097/00125817-200001000-00198
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DOI: https://doi.org/10.1097/00125817-200001000-00198