S082 Atypical Facial Access: An Unusually High Prevalence Among Patients With Skull Base Tumors Treated in 2 Centers

terminedbyrestriction fragment lengthpolymorphismutilizingrestrictionenzymes.Allele-specificexpressionanalysiswithreversetranscriptase–polymerasechainreactionand digestionsbyrestrictionenzymeswereperformedunderthe same conditions as for detecting genomic polymorphisms. Results: Loss of imprinting (LOI) showed 1 of 2 informative cases at IGF2 in both normal and tumor specimens; 4 of 4 informative cases were detected in tumor specimens; and 3 of 4 informative cases were detected even in normal specimens at PEG1/MEST. As for the cell lines, LOI showed 5 of 8 informative cases in PEG1/MEST and 6 of 10 informative cases in IGF2; LOI of both imprinted genes was observed in 2 cancer cells. Conclusions: As a result of analyzing tissue samples and cell lines, frequent LOI of PEG1/MEST as well as IGF2 was observed. We identified the epigenetic changes at PEG1/MEST in head and neck cancer.