Recurrent 12q13-15 Chromosomal Aberrations, High Frequency of Isocitrate Dehydrogenase 1 Mutations, and Absence of High Mobility Group AT-hook 2 Expression in Periosteal Chondromas

Periosteal chondroma is a benign cartilage tumor that accounts for <2% of chondromas. In the present study, four cases of periosteal chondromas were cytogenetically investigated and studied for the expression of high-mobility group AT-hook 2 (), mutations in codons 132 of isocitrate dehydrogenase ()1 and 172 of ; mutations -C228T and -C250T in the promoter region of telomerase reverse transcriptase (); and for methylation in the promoter regions of -6-methylguanine-DNA methyltransferase () and cellular retinol binding protein 1 (). Chromosome aberrations of 12q13-15 were found in two out of the four tumors, while two had a normal karyotype. Two periosteal chondromas carried the mutation IDH1R132C (CGT>TGT), and two carried the mutation IDH1R132L (CGT>CTT). However, none of the four tumors had methylated and promoters or mutations at codon 172 of . In addition, -C228T and -C250T mutations were not present in the promoter region of , nor was demonstrated to be expressed. The present study indicated that in periosteal chondromas, the involvement of 12q13-15 in structural rearrangements may be recurrent but that is not expressed. Additionally, the periosteal chondromas investigated in the study carried a heterozygous IDH1R132 mutation, the and promoters were not methylated, and -C228T and -C250T mutations in the promoter region of were absent.