The leiomyomas that were treated with GnRHa highly expressed the estrogen/progesterone receptor genes, insulin-like growth factor 2 (IGF2) and embryonic smooth muscle myosin heavy chain (SMemb), which suggests that these factors are critical in the establishment of a mouse model of growing leiomyoma.
The low expression level of insulin-like growth factor (IGF-2), a fibroid specific marker, that we found in the PC and the UM when compared with the UL, clearly indicates that the PC is in structural continuity with the UM.
Low-grade leiomyosarcomas contained more IGF-II mRNAs than myometrium and leiomyoma, fewer type II IGF/mannose 6-phosphate receptors and less IGFBP-3 than myometrium and, in addition, fewer IGF-I mRNAs and type I IGF receptors than leiomyoma.
These results demonstrated that IGF2 and SNRPN imprinting is completely maintained in human uteri and leiomyomas and that increased expression of IGF2 is not due to biallelic expression.
The data showed that in fibroids compared to myometrium, 1) the relative abundance of IGF-I mRNA was not different, but there was an increase in the relative abundance of IGF-II mRNA (P < 0.001); 2) IGFBP-1 mRNA was undetectable in fibroids and detectable in only 1 specimen of myometrium; 3) there was no difference in the relative abundance of IGFBP-2 mRNA, but there was an increase in the relative abundance of IGFBP-3 mRNA in myometrium (P < 0.05).