Comet assay in myelodysplastic syndromes

Abstract

The comet assay (single-cell gel electrophoresis) has been established as a simple, rapid, flexible and sensitive method of detecting DNA damage in single cells(1,2). Cells embedded in agarose on a microscope slide are lysed with detergent. Electrophoresis at high pH results in structures resembling comets, observed by fluorescence microscopy; the intensity of the comet tail relative to the head reflects DNA damage(2). The lesion of each cell is quantified according to the comet tail length as class 0 (no tail) to 4 (almost all DNA in tail)(3). Due to genetic instability of myelodysplastic syndromes, the comet assay can be useful to detect DNA lesion intensity and correlate this with cytogenetic abnormalities. Figure 1 illustrates a cell from a healthy 46-year-old control individual classified as comet class 0. Figures 2A - E illustrate cells from a 61-year-old patient with myelodysplastic syndrome (47, XY, +8) classified as comet class 0, 1 and 2. Figure 1 - Figures 2A – E Electrophoresis under alkaline conditions in low melting point agarose gel of the cells of a healthy control classified as comet Class 0.