IGF2 and leiomyoma: Gloudemans et al., observed that in malignant smooth muscle tumors (leiomyosarcomas), the overall methylation of the IGF-2 gene was low or absent and related to increased gene expression, while in normal smooth muscle tissues (myometrium) and benign smooth muscle tumors (leiomyomas) IGF-2 was hypermethylated [55].