Geneeskundige Stichting Koningin Elisabeth ... - GSKE - FMRE

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Fig. 1. illustrates the results of two microsatellites for a single tumour (tumoral reference
22442-a). Analysis is always done in duplicate for the tumour and its control (blood). This is to
avoid misinterpretation of artefactual monoallelic amplification which sometimes occurs due to
weaker quality of the DNA extracted from formaline-fixed tissue.
Fig. 1: Autoradiogram of two markers for tumour 22442-a
For both microsatellites, D1S468 and
D19S178, two alleles are detected in the
patient’s blood (score 12 in Fig. 1 and in the
table below) while the tumour has only the
lower allele (score 11 in Fig. 1 and in the table
below). This indicates loss of one allele for both
microsatellites in this tumour, and thus of their
respective loci on chromosomes 1p and 19q.
The analysis of several consecutive microsatellites
on a given chromosome permits to
identify the extend of the deleted area. For
example, for the tumour (22442-a) in the table
below, all analysed microsatellites for 1p and
19q show allelic loss when compared to the
patient’s blood (CG32)