TY - JOUR
T1 - Enhanced expression of telomerase activity in thymoma and thymic carcinoma tissues
T2 - A clinicopathologic study
AU - Watanabe, Masazumi
AU - Yu, Shan Kang
AU - Sawafuji, Makoto
AU - Kawamura, Masafumi
AU - Horinouchi, Hirohisa
AU - Mukai, Makio
AU - Kobayashi, Koichi
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2002/1/1
Y1 - 2002/1/1
N2 - BACKGROUND. Telomerase is a nucleoprotein complex that caps the physical termini of all eukaryotic chromosomes. Because most malignant cells and reproductive cells have telomerase activity, which elongates telomeric DNA, telomerase may play important roles in unlimited cell division acquisition of the malignant phenotype. The current study examined the relation of telomerase activity in thymoma and thymic carcinoma with the clinicopathologic features of these lesions. METHODS. Tissue specimens were surgically resected from patients with thymoma and thymic carcinoma. Telomerase activity was evaluated according to a modified telomeric repeat amplification protocol assay. Paraffin sections of tumor were immunostained by MIC2 antibody, a marker of immature T cells. RESULTS. Telomerase activity was detected in all thymic epithelial tumors. The activity (mean ± SD; unit per μg protein) in thymoma (n = 17) was significantly higher than that in thymic carcinoma (n = 7) (431.8 ± 400.1 vs. 68.8 ± 39.8; P < 0.01). Telomerase activities in thymoma and thymic carcinoma were significantly higher than that in primary lung adenocarcinoma (33.5 ± 39.2, n = 47), studied as a control (P < 0.01). In patients with thymoma, telomerase activity did not correlate with tumor stage according to Masaoka classification (P = 0.776). In patients with thymic carcinoma, however, telomerase activity positively correlated with tumor stage (P = 0.02). In thymoma, telomerase activity positively correlated with the ratio of induced lymphocytes according to Rosai's classification (P = 0.045). MIC2-positive lymphocytes were identified in all cases of thymoma (n = 12). In contrast, lymphocytes infiltrating thymic carcinoma did not react with MIC2. CONCLUSIONS. In thymoma, telomerase activity reflects the presence of immature T-cell lymphocytes in tumor tissue rather than tumor stage or malignant phenotype. In thymic carcinoma, telomerase activity derived directly from cancer cells may relate to tumor stage.
AB - BACKGROUND. Telomerase is a nucleoprotein complex that caps the physical termini of all eukaryotic chromosomes. Because most malignant cells and reproductive cells have telomerase activity, which elongates telomeric DNA, telomerase may play important roles in unlimited cell division acquisition of the malignant phenotype. The current study examined the relation of telomerase activity in thymoma and thymic carcinoma with the clinicopathologic features of these lesions. METHODS. Tissue specimens were surgically resected from patients with thymoma and thymic carcinoma. Telomerase activity was evaluated according to a modified telomeric repeat amplification protocol assay. Paraffin sections of tumor were immunostained by MIC2 antibody, a marker of immature T cells. RESULTS. Telomerase activity was detected in all thymic epithelial tumors. The activity (mean ± SD; unit per μg protein) in thymoma (n = 17) was significantly higher than that in thymic carcinoma (n = 7) (431.8 ± 400.1 vs. 68.8 ± 39.8; P < 0.01). Telomerase activities in thymoma and thymic carcinoma were significantly higher than that in primary lung adenocarcinoma (33.5 ± 39.2, n = 47), studied as a control (P < 0.01). In patients with thymoma, telomerase activity did not correlate with tumor stage according to Masaoka classification (P = 0.776). In patients with thymic carcinoma, however, telomerase activity positively correlated with tumor stage (P = 0.02). In thymoma, telomerase activity positively correlated with the ratio of induced lymphocytes according to Rosai's classification (P = 0.045). MIC2-positive lymphocytes were identified in all cases of thymoma (n = 12). In contrast, lymphocytes infiltrating thymic carcinoma did not react with MIC2. CONCLUSIONS. In thymoma, telomerase activity reflects the presence of immature T-cell lymphocytes in tumor tissue rather than tumor stage or malignant phenotype. In thymic carcinoma, telomerase activity derived directly from cancer cells may relate to tumor stage.
KW - MIC2
KW - Mediastinal tumor
KW - Telomerase
KW - Thymic carcinoma
KW - Thymoma
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U2 - 10.1002/cncr.10194
DO - 10.1002/cncr.10194
M3 - Article
C2 - 11815982
AN - SCOPUS:0036140599
VL - 94
SP - 240
EP - 244
JO - Cancer
JF - Cancer
SN - 0008-543X
IS - 1
ER -