Figure 1  MLPA for analysis of gene dosage at chromosome 9p21. A, a diagrammatical representation of the 9p21 region covered by the P024A MLPA kit. Locations of probed genes are shown in green and MLPA probes in orange with probe names outlined in bold. Probe groupings used in data analysis are represented by orange bars with black dots at top of the picture. B, gene dosage ratios for a representative primary melanoma sample showing an almost total loss of gene dosage (representing ≥80% loss) from MTAP exon 6 to CDKN2B intron.