Hiyama E, Yamaoka H, Matsunaga T, Hayashi Y, Ando H, Suita S, Horie H, Kaneko M, Sasaki F, Hashizume K, Nakagawara A, Ohnuma N, Yokoyama T
Natural Science Center for Basic Research and Development, Hiroshima University, Hiroshima, Japan.
Br J Cancer. 2004 Aug 31;91(5):972-9. doi: 10.1038/sj.bjc.6602054.
Telomerase, an enzyme related with cellular immortality, has been extensively studied in many kinds of malignant tumours for clinical diagnostic or prognostic utilities. Telomerase activity is mainly regulated by the expression of hTERT (human telomerase reverse transcriptase), which is a catalytic component of human telomerase. To evaluate whether the levels of hTERT mRNA provides a molecular marker of hepatoblastoma malignancy, we examined hTERT mRNA expression levels in the primary hepatoblastoma tissues by fluorescent RT-PCR using LightCycler technology and followed up the clinical outcomes in 63 patients listed in the Japanese Study Group of Pediatric Liver Tumor between 1991 and 2002. The hTERT mRNA expression was detected in 61 (96.8%) specimens and their expression levels ranged between 0.1/1000 and 745.1/1000 copies of PBGD gene that was used as an internal control. Among these cases, frozen 39 tumour samples and 14 adjacent noncancerous liver tissues were analysed for semiquantitative telomerase assay. In the 39 tumour samples, the levels of telomerase activity ranged between 0.11 and 2709 TPG and 12 (30.7%) had high telomerase activity (>100 TPG), whereas only nine of 14 noncancerous liver tissue samples showed telomerase activity which was less than 1.0 TPG. The levels of telomerase activity were significantly correlated with the levels of hTERT mRNA expression (P<0.001). The frequency of high hTERT mRNA expression and/or high telomerase activity did not significantly associate with the clinicopathological factors except for stage of disease. The prognosis of the patients with high hTERT mRNA expression was significantly worse than that of others (P<0.01), as was the patients with high telomerase activity (P<0.01). Multivariate analysis indicated that high levels of hTERT mRNA expression as well as telomerase activity are independent prognosis-predicting factors in patients with hepatoblastoma.
端粒酶是一种与细胞永生相关的酶，已在多种恶性肿瘤中进行了广泛研究，以用于临床诊断或预后评估。端粒酶活性主要受hTERT（人端粒酶逆转录酶）表达的调节，hTERT是人类端粒酶的催化成分。为了评估hTERT mRNA水平是否可作为肝母细胞瘤恶性程度的分子标志物，我们使用LightCycler技术通过荧光逆转录聚合酶链反应检测了原发性肝母细胞瘤组织中hTERT mRNA的表达水平，并对1991年至2002年间日本小儿肝脏肿瘤研究组列出的63例患者的临床结局进行了随访。在61份（96.8%）标本中检测到hTERT mRNA表达，其表达水平在用作内对照的PBGD基因的0.1/1000至745.1/1000拷贝之间。在这些病例中，对39份冷冻肿瘤样本和14份相邻的非癌性肝组织进行了半定量端粒酶检测。在39份肿瘤样本中，端粒酶活性水平在0.11至2709 TPG之间，12份（30.7%）具有高端粒酶活性（>100 TPG），而14份非癌性肝组织样本中只有9份显示端粒酶活性低于1.0 TPG。端粒酶活性水平与hTERT mRNA表达水平显著相关（P<0.001）。除疾病分期外，hTERT mRNA高表达和/或端粒酶活性高的频率与临床病理因素无显著相关性。hTERT mRNA高表达患者的预后明显比其他患者差（P<0.01），端粒酶活性高的患者也是如此（P<0.01）。多变量分析表明，hTERT mRNA高表达水平以及端粒酶活性是肝母细胞瘤患者独立的预后预测因素。
