Different therapeutic methods have been developed for the B-cell and T-cell subtypes of acute lymphoblastic leukemia (ALL). The identification of molecular biomarkers that can accurately discriminate between B-cell and T-cell ALLs will facilitate the quick determination of therapeutic plans, as well as reveal the intrinsic mechanisms underlining the two different ALL subtypes. This study computationally screened the high-throughput transcriptome dataset for multiple candidate biomarkers and verified their discrimination abilities in an independent sample set using quantitative real-time polymerase chain reaction (PCR) technology. Both technologies suggest that the two genes CD3D and PKRCQ together provided a good model for classification of B-cell and T-cell ALLs, whereas the individual genes did not show consistent discrimination between the two ALL subtypes. Supplementary material is available at http://healthinformaticslab.org/supp/.

Bladder cancer diagnosis and patient surveillance present a wide range of diagnostic methods but essentially only instrumental approaches are available in the clinical setting. Although numerous new noninvasive biomarkers have been proposed in the last 10 years, few are US FDA-approved for clinical purposes, and none are widely used in routine clinical practice. In this review, we summarize the tests developed for early diagnosis and patient surveillance and verify whether, for any, there is some level of evidence to suggest a real usefulness in a clinical setting.

The expression of the telomerase subunits such as human telomerase reverse transcriptase (hTERT) and human telomerase RNA component (hTR) may be associated with tumor development and progression. We evaluated the relationship between mRNA quantification of both hTERT and hTR and clinicopathologic parameters in bladder cancer.

We examined the mRNA expression of hTERT and hTR in 29 specimens with bladder cancer (Grade: Grade I, 9 cases; Grade II, 13 cases and Grade III, 7 cases. Stage: pTa-pT1, 18 cases; pT2-T4, 11 cases). We immediately froze all of specimens obtained during TUR-Bt and isolated the total RNA from each specimen. We measured the quantity of hTERT, hTR and GAPDH mRNA by a real-time reverse transcription-polymerase chain reaction method based on TaqMan technology.

The hTERT/GAPDH mRNA ratio and hTERT mRNA/total RNA in superficial bladder tumor was significantly lower than in invasive bladder tumor. The hTR/GAPDH mRNA ratio and hTR mRNA/total RNA in superficial tumor were significantly lower than in invasive bladder tumor. The hTERT mRNA expression significantly correlated with tumor grade, but the hTR mRNA expression did not correlate with tumor grade. There was no significant difference in the hTERT/GAPDH mRNA ratio and hTR mRNA/total RNA according to multiplicity of bladder tumor.

Our results demonstrated that the expression of hTERT mRNA correlated with the progression of stage and grade in bladder cancer. The quantitative analysis of hTERT and hTR mRNA might be a marker for clinicopathologic parameters in bladder cancer.

Telomerase is a ribonucleoprotein enzyme that compensates for the telomere length shortening which occurs during the cell cycle. Telomerase activity has been detected in most tumours but not in somatic cells. However, hTR; the RNA component of telomerase; has been reported to be universally expressed in both cancerous and non-cancerous tissues. Tumour samples from 50 patients with primary invasive breast cancer were collected. The TRAP assay was used to detect telomerase activity. RT-PCR on cDNA and DNased cDNA samples and control groups was used to detect the expression of hTR, GAPDH and PGM1 genes. Seventy-two percent of samples showed telomerase activity. DNA contamination was detected in 36 (72%) of RNA samples. Without performing DNase treatment, 49 (98%) of all samples showed hTR expression, but with the application of this strategy, hTR expression decreased from 98% to 64%. A significant association (p < 0.001) between hTR expression and telomerase activity was observed. Among the 32 hTR positive samples, 30 had telomerase activity and among the 18 hTR negative samples, telomerase activity was observed in 6 cases. Thus the application of this strategy could provide an applicable tool to use instead of the TRAP assay thus facilitating telomerase research in cancer genetic investigations.

h-TERT is the keystone gene in controlling telomerase expression under the modulation of many associated genes. Our study was designed to observe the concordant expression of the telomerase associated genes in NSCLC (non-small cell lung cancer).

Between January 1999 and December 1999, 78 NSCLC patients were studied. The telomerase activity was measured by TRAP (telomeric repeat amplification protocol) assay, and the associated genes (h-TERT, h-TERC, TP1, c-Myc, TRF1, and TRF2) were detected using RT-PCR method.

Positive telomerase activity was identified in 47 (60.3%) patients. Expression of the h-TERT, h-TERC, TP1, c-Myc, TRF1 and TRF2 genes were observed in 66.6, 92.3, 100.0, 91.0, 74.4 and 83.3% of the tumor tissues, respectively. Higher expression of the telomerase activity was found in advanced T-status (p=0.0265), and late TNM stages (p=0.0497) patients. In addition to the tumor tissue itself (p<0.0001), higher telomerase expression rates were observed in positive h-TERT (p<0.0001), and positive TRF1 (p=0.003) tumor tissues compared to their normal counterparts. Furthermore, h-TERT expression was closely related to the TRF1 (p=0.003), TRF2 (p=0.024), and c-Myc (p=0.042) expression.

Our data demonstrate that expression of the telomerase activity can be observed in the majority of NSCLC tumor tissues, and is also closely related to the T-status and TNM stage of the tumor. h-TERT expression and subsequent telomerase activation leads to telomere repair under modulation by the TRF1, TRF2 and c-Myc genes.

Telomerase is an RNA-dependent DNA polymerase that synthesizes TTAGGG telomeric DNA onto chromosome ends to compensate for sequence loss during DNA replication. It has been detected in 85-90% of all primary human cancers, implicating that the telomerase seems to be reactivated in tumors and that such activity may play a role in the tumorigenic process. The purpose of this study was to evaluate telomerase activity, human telomerase RNA (hTR), and telomerase reverse transcriptase (TERT) in stomach cancer and to determine their potential relationships to clinicopathologic parameters. Frozen and corresponding methacarn-fixed paraffin-embedded tissue samples were obtained from 51 patients with gastric adenocarcinoma and analyzed for telomerase activity by using a TRAPeze ELISA kit. Tissue sections of all the samples were further investigated for hTR and TERT by in situ hybridization and a sensitive immunohistochemical technique, respectively. Telomerase activity was detected in 37 (73%) tumors. Telomerase positivity from methacarn-fixed paraffin blocks was found to be 35% of that from frozen tissues. hTR was overexpressed in 46 (90%) samples: 33/37 (89%) with and 13/14 (93%) without telomerase activation. Expression of TERT was demonstrated in 40 (78%) cases: 30/37 (81%) with and 10/14 (71%) without telomerase. Telomerase activity correlated well with depth of invasion (P =.037) and tumor differentiation (P =.022), whereas hTR significantly correlated with nodal metastasis (P=.047) and tumor size (P=.023). These data suggest that reactivated telomerase may play a significant role in the tumorigenesis of gastric cancer and may reflect, along with enhanced hTR, the malignant potential of the tumor. It is noteworthy that methacarn-fixed tissue cannot as yet substitute for the frozen section in the TRAP assay.

The reactivation of telomerase is believed to play an important role in immortalization and carcinogenesis.

To investigate the expression of three components of the telomerase complex (hTR, hTERT and TP1), along with telomerase activity in malignant and normal cells.

Cells were isolated from gastric and colon cancer, and from normal mucosa from the stomach and colon of participating patients. Expression of hTERT, hTR and TP1 has been studied by the reverse transcriptase polymerase chain reaction (PCR) technique. The telomerase repeat amplification protocol and PCR enzyme-linked immunosorbent assay were used for analysis of telomerase activity.

All telomerase components were consistently expressed in colon and gastric cancer cells. Neoplastic RNA produced consistently very strong amplification signals either for hTR, hTERT or TP1. The expression of hTR was observed in RNA isolated from all normal mucosa samples and from peripheral blood lymphocytes. The expression of TP1 and hTERT has been found in the majority of normal cells; however, the amplification signals produced were usually much weaker than in malignant cells. The limiting dilution experiments indicated that the cancer cells have at least 100-fold higher telomerase activity and at least 25-fold higher TP1 and hTERT expression in comparison to normal cells.

It can be concluded that all the cancer cells tested have higher telomerase expression and activity than normal cells. Therefore, telomerase can be a good cancer marker, provided that quantitative analysis is carried out.

Epidermal growth factor receptor is overexpressed and/or amplified in up to 50% of glioblastomas, suggesting an important role of this gene in glial tumorigenesis and progression. In the present study we demonstrated that epidermal growth factor receptor is involved in regulation of telomerase activity in glioblastoma. Antisense-epidermal growth factor receptor approach was used to inhibit epidermal growth factor receptor expression of glioblastoma U87MG cells. Telomerase activity in antisense-epidermal growth factor receptor cells decreased by up to 54 folds compared with control cells. Moreover, the telomere lengths of antisense-epidermal growth factor receptor cells were shortened. In addition, the tumorigenicity of antisense-epidermal growth factor receptor cells was significantly inhibited. Taken together, there were strong correlations between tumorigenicity and epidermal growth factor receptor expression levels, and between tumorigenicity and telomerase activity. These results provide evidence that epidermal growth factor receptor plays an important role in the regulation of telomerase activity of glioma cells. Our findings provide new insights into both the biological functions of epidermal growth factor receptor and the regulation of telomerase activity. The inhibition of telomerase activity triggered by antisense-epidermal growth factor receptor treatment may reflect yet another mechanism of antisense-epidermal growth factor receptor approach in tumour suppression.

In the current study, the quantitative levels of telomerase hTERT mRNA and the functional telomerase repeat amplification protocol (TRAP) assay were correlated with tumor grade in endometrial carcinomas and with the histologic phase of normal endometrium.

Twenty-six samples of endometroid adenocarcinoma and 20 cases of benign endometrium were obtained from hysterectomy specimens. Total RNA was extracted from each tissue sample and used for quantitative real-time RT-PCR of hTERT mRNA and the levels were standardized to the levels of ribosomal RNA. Quantitative determination of telomerase activity was performed by the polymerase chain-based TRAP assay and the levels of expression were defined by the ratio of radioactivity incorporated into the 6-bp telomerase amplification products versus the radioactivity incorporated into an internal standard (telomerase/ITAS x 100 = 1 RU). Statistical analyses were performed using the Fisher exact test or chi2 test, a Wilcoxon rank sum test, and a linear regression analysis.

hTERT mRNA and telomerase activity levels showed a linear association in the study group (P = 0.006, R2 = 0.139). hTERT mRNA levels and telomerase activity levels were significantly higher in endometrial cancer (179 pg/ng rRNA, 44 relative units (RU)) than in normal endometrium (45 pg/ng), (15 RU) (P = 0.009, P = 0.006). In normal endometrium, hTERT mRNA and telomerase activity levels were highest in the proliferative phase (74 pg/ng rRNA, 25 RU) and were relatively low in secretory (13 pg/ng rRNA, 6 RU) and atrophic endometrium (9 pg/ng rRNA, 2 RU).

These results suggest that the quantitative analysis of hTERT and telomerase activity may have potential roles as diagnostic or prognostic adjuncts for both premenopausal and postmenopausal patients with endometrial cancer.