TY - JOUR
T1 - p16 INK4, pRB, p53 and cyclin D1 expression and hypermethylation of CDKN2 gene in thymoma and thymic carcinoma
AU - Hirabayashi, Hirohisa
AU - Fujii, Yoshitaka
AU - Sakaguchi, Masahiro
AU - Tanaka, Hisaichi
AU - Yoon, Hyung Eun
AU - Komoto, Yosuke
AU - Inoue, Masahiro
AU - Miyoshi, Shinichiro
AU - Matsuda, Hikaru
PY - 1997/11/27
Y1 - 1997/11/27
N2 - There have been few reports on genetic alterations in thymomas. To investigate the expression of p16INK4A, RB, p53 and cyclin D1 in thymomas, we first examined 36 thymomas (non-invasive type, 16 cases; invasive type, 20 cases) and 3 thymic carcinomas, using immunohistochemistry. Abnormal expression of p16INK4A, RB, p53 and cyclin D1 was observed in 18, 8, 10 and 7 cases, respectively. Only a subgroup of invasive thymomas and thymic carcinomas showed an inverse correlation between p16INK4A and RB expression. Subsequently, we examined the 36 thymomas and 4 thymic carcinomas for mutations in p53 and CDKN2 genes, using PCR-SSCP and direct-sequencing analyses. No mutation of these genes was detected in the thymomas and thymic carcinomas examined. A polymorphism in the 3′ untranslated region of exon 3 of CDKN2 was detected in 5 cases of thymoma. We searched for hypermethylation in the promoter region of CDKN2, observing it in 4 thymomas and 1 thymic carcinoma. Our data suggest that, unlike other more common cancers, alteration of the p53 gene may not play a significant role in the tumorigenesis of thymoma. However, inactivation of p16INK4A and RB may play a role in the progression of thymoma and thymic carcinoma.
AB - There have been few reports on genetic alterations in thymomas. To investigate the expression of p16INK4A, RB, p53 and cyclin D1 in thymomas, we first examined 36 thymomas (non-invasive type, 16 cases; invasive type, 20 cases) and 3 thymic carcinomas, using immunohistochemistry. Abnormal expression of p16INK4A, RB, p53 and cyclin D1 was observed in 18, 8, 10 and 7 cases, respectively. Only a subgroup of invasive thymomas and thymic carcinomas showed an inverse correlation between p16INK4A and RB expression. Subsequently, we examined the 36 thymomas and 4 thymic carcinomas for mutations in p53 and CDKN2 genes, using PCR-SSCP and direct-sequencing analyses. No mutation of these genes was detected in the thymomas and thymic carcinomas examined. A polymorphism in the 3′ untranslated region of exon 3 of CDKN2 was detected in 5 cases of thymoma. We searched for hypermethylation in the promoter region of CDKN2, observing it in 4 thymomas and 1 thymic carcinoma. Our data suggest that, unlike other more common cancers, alteration of the p53 gene may not play a significant role in the tumorigenesis of thymoma. However, inactivation of p16INK4A and RB may play a role in the progression of thymoma and thymic carcinoma.
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U2 - 10.1002/(sici)1097-0215(19971127)73:5<639::aid-ijc5>3.0.co;2-y
DO - 10.1002/(sici)1097-0215(19971127)73:5<639::aid-ijc5>3.0.co;2-y
M3 - Article
C2 - 9398039
AN - SCOPUS:0031588376
VL - 73
SP - 639
EP - 644
JO - International Journal of Cancer
JF - International Journal of Cancer
SN - 0020-7136
IS - 5
ER -