SOCS1 and plasma cell myeloma: Tumor suppressing activity of SOCS1 is also supported by the high frequency of SOCS1 gene silencing by DNA hypermethylation in different cancer cell lines and in human malignant diseases such as multiple myeloma[45], acute myeloid leukemia[46,47], hepatocellular carcinoma[48], ovarian and breast carcinomas.[25] In CML, however, results of epigenetic analyses of the SOCS1 gene are conflicting.