Methylation status of EXT1 and EXT2 promoters and two mutations of EXT2 in chondrosarcoma.
Germline mutation and functional loss of EXT1 or EXT2 are commonly found in multiple osteochondromas and predispose to the development of chondrosarcoma. Mutations of EXT1 and EXT2 have rarely been detected in sporadic secondary chondrosarcomas from osteochondroma; these frequently display loss of heterozygosity at the EXT1 and EXT2 loci, but primary chondrosarcomas typically do not. To evaluate promoter methylation (which is an epigenetic gene silencing mechanism) of EXT1 and EXT2, we performed methylation-specific polymerase chain reaction (PCR) for 20 chondrosarcoma cases (12 primary, 3 secondary to osteochondroma, 2 secondary to enchondromatosis, 2 extraskeletal ordinary, and 1 clear cell) and in five cell lines. In addition, mutation analysis of the EXT1 and EXT2 coding regions was performed using PCR-single-strand conformation polymorphism and sequencing analysis for 12 of the 20 chondrosarcoma cases (8 primary, 1 secondary to enchondromatosis, 1 secondary to osteochondroma, and 2 extraskeletal ordinary) and five cell lines. Promoter methylation of EXT1 and EXT2 was not detected in any of the cases, and both EXT1 and EXT2 were expressed in all cell lines. Two missense mutations in EXT2 (D227E and R299H) were detected among the chondrosarcoma cases. When considering tumor development in primary chondrosarcoma, we should include mutations in EXT2, along with the status of other members of the EXT gene family.
Tsuchiya
Takashi
T
Department of Orthopaedic Surgery, Yamagata University School of Medicine, Yamagata, Japan. tsuchiya@med.id.yamagata-u.ac.jp
Osanai
Toshihisa
T
Ogose
Akira
A
Tamura
Gen
G
Chano
Tokuhiro
T
Kaneko
Yasuhiko
Y
Ishikawa
Akira
A
Orui
Hiroshi
H
Wada
Takuro
T
Ikeda
Tatsuru
T
Namba
Masayoshi
M
Takigawa
Masaharu
M
Kawashima
Hiroyuki
H
Hotta
Tetsuo
T
Tsuchiya
Atsushi
A
Ogino
Toshihiko
T
Motoyama
Teiichi
T
D020121:5' Untranslated Regions; D000293:Adolescent; D000328:Adult; D000368:Aged; D001483:Base Sequence; D002813:Chondrosarcoma / Q000145:classification / Q000235:genetics* / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D004252:DNA Mutational Analysis; D005260:Female; D018095:Germ-Line Mutation; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D017351:N-Acetylglucosaminyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000099065:Exostosin 2; D000099058:Exostosin 1
D020121:5' Untranslated Regions; D017351:N-Acetylglucosaminyltransferases; D000099058:Exostosin 1; D000099065:Exostosin 2