SOCS-1 is frequently hypermethylated in MM patient samples.

Representative MSP results from primary MM samples are shown. Lane U indicates amplified product with primers recognizing unmethylated SOCS-1 sequence. Lane M indicates amplified product with primers recognizing methylated SOCS-1 sequence. None of these samples were enriched for plasma cells, so the occurrence of both signals in the same sample indicates either the presence of nonmalignant cells in the bone marrow aspirate or heterogeneity of aberrant methylation within the MM cell population.