H19 and synovial sarcoma: Loss of imprinting (LOI) concurrent to hypomethylation at the H19/IGF2 intergenic region has been observed in a limited number of primary synovial sarcomas [39] and SYT-SSX expression has been shown to induce IGF2 in immortalized MRC5 fibroblasts [39] and HEK 293 cells [27].