ALK and anaplastic large cell lymphoma: Using bisulphite conversion, RNAse cleavage and MALDI–TOF mass spectroscopic analysis, we analysed the methylation status of these regions in two ALCL ALK− cell lines with high miR-155 expression levels (Mac1, Mac2a) and three ALCL ALK+ cell lines with low miR-155 expression levels (Karpas-299, SR786, SUP-M2).