RELAXATION OF INSULIN-LIKE GROWTH-FACTOR-II GENE IMPRINTING IN HUMAN GYNECOLOGIC TUMORS

To test for the existence of genomic imprinting in human gynecologic t umors, we analyzed the allelic expression of human insulin-growth fact or-II (IGF-II) genes. Genomic imprinting is the parental allele-specif ic expressions of genes, and recently imprinting of IGF-II gene has de monstrated that parental IGF-II was monoallelically expressed. To stud y whether IGF-II gene imprinting occurs in human gynecologic tumors, w e examined allele-specific expression using an ApaI polymorphism in th e 3' untranslated region of IGF-II gene exon 9. We used 19 gynecologic tumor cell lines, and 66 human gynecologic tumors. Four of 19 cell li nes (21%) were informative, and three of these four cell lines (75%) r evealed loss of imprinting (LOI). For gynecologic tumors, 24 of 66 wer e informative (36%), and 5 of the 24 (21%) had LOI. We have reported h ere that the IGF-II gene is expressed biallelically in some gynecologi c tumors, We suggest that LOI of the IGF-II gene is involved in the de velopment of some gynecologic tumors.