Aberrant methylation: common in thymic carcinomas, rare in thymomas.
Thymic carcinoma, which is a rare epithelial neoplasm of the thymus gland, is different from thymoma in its clinical and pathological features. To clarify the mechanism underlying the aggressive behavior of thymic carcinoma, we examined the clinicopathologic features, aberrant methylation patterns of the tumor suppressor genes, and epidermal growth factor receptor (EGFRs) mutation in both thymic carcinomas and thymomas. Clinical data of 11 thymic cancers and 13 thymomas were reviewed. Resected samples of 5 thymic cancers and 6 thymomas selected from 24 cases were used for methylation and mutation studies. Positive tumor markers were more frequent in thymic cancers than in thymomas (p=0.0233), and the methylation index, which reflects the overall methylation pattern, was significantly higher in thymic carcinomas (p=0.0053). No tumors showed a mutation of EGFR, KRAS, and HER2. Thymic carcinoma is distinct from thymoma not only with respect to clinicopathological features, but also aberrant methylation patterns of the tumor suppressor genes.
Suzuki
Makoto
M
Department of Thoracic Surgery, Graduate School of Medicine, 1-8-1 Inohana, Chuoh-ku, Chiba 260-8677, Japan. smakoto@faculty.chiba-u.jp
Chen
Hong
H
Shigematsu
Hisayuki
H
Ando
Soichiro
S
Iida
Tomohiko
T
Nakajima
Takahiro
T
Fujisawa
Takehiko
T
Kimura
Hideki
H
D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000473:pathology; D018797:Cell Cycle Proteins / Q000235:genetics; D019175:DNA Methylation; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D006023:Glycoproteins / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D016019:Survival Analysis; D013945:Thymoma / Q000235:genetics / Q000473:pathology*; D013953:Thymus Neoplasms / Q000235:genetics / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000235:genetics; D018631:ras Proteins / Q000235:genetics
D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D066246:ErbB Receptors; D006023:Glycoproteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D025521:Tumor Suppressor Proteins; D018631:ras Proteins; C411762:RASSF1 protein, human; C412566:RPRM protein, human