Expression of telomerase mRNA component (hTR) in transitional cell carcinoma of the upper urinary tract

Effect of the TERT mutation on the prognosis of patients with urothelial carcinoma: a systematic review and meta-analysis

BACKGROUND

Telomerase reverse transcriptase (TERT) mutation represents the most prevalent genetic mutation found in urothelial carcinoma (UC) and holds potential as a prognostic indicator for tumor outcomes. However, the association between TERT mutation and prognosis in UC patients remains poorly elucidated due to conflicting findings in existing literature. Therefore, this study aimed to investigate the effect of the TERT mutation on the survival of UC patients.

METHODS

We systematically searched the PubMed, Embase, and Cochrane Library databases for studies that investigated the relationship between the TERT mutation and the prognosis of UC patients. Endpoints included the 2-year and 5-year recurrence-free survival (RFS) and overall survival (OS). The Newcastle-Ottawa Scale (NOS) tool was used to assess the risk of bias in the included studies. Review Manager 5.3 was used for the meta-analysis.

RESULTS

Nine studies with a total of 1,552 patients were included in the analysis. Two studies were prospective, and seven were retrospective. The TERT promoter mutation was associated with a lower 2-year OS (relative risk [RR] = 0.92, 95% confidence interval [CI] 0.86-0.98; P = 0.007) and a lower 5-year OS (RR = 0.80, 95% CI 0.68-0.94; P = 0.008) compared with the TERT wild type. However, no significantly differences were found between two groups in terms of HR for OS (hazard ratio [HR] = 1.29, 95% CI 0.80-2.08; P = 0.29). Furthermore, we investigated the differences in RFS and disease-specific survival (DSS) between the two groups.

CONCLUSION

The TERT mutation increases the risk of death and decreases the survival time of UC patients. TERT may be a valuable marker with individual prognostic value.

Identification of circulating microRNA signatures for upper tract urothelial carcinoma detection

The involvement of circulating microRNAs (miRNAs) in cancer and their potential as diagnostic and prognostic biomarkers are becoming increasingly known. However, the significance of circulating miRNAs in upper tract urothelial carcinoma (UTUC) has remained to be investigated. The present study performed a genome‑wide serum miRNA analysis using a deep sequencing platform for initial screening. Subsequently, serum samples of 46 UTUC patients and 30 cancer‑free individuals with hematuria were subjected to a quantitative reverse‑transcription polymerase chain reaction analysis. The expression of thirteen miRNAs (miR‑664a‑3p, miR‑423‑5p, miR‑431‑5p, miR‑191‑5p, miR‑92a‑3p, miR‑22‑3p, miR‑26a‑5p, miR‑33b‑3p, miR‑16‑5p, let‑7a‑5p, let‑7b‑5p, let‑7f‑5p and let‑7c) was significantly different in serum from UTUC patients compared with that in control samples. Receiver operator characteristic analysis showed that 10 miRNAs (miR‑664a‑3p, miR‑431‑5p, miR‑423‑5p, miR‑191‑5p, miR‑33b‑3p, miR‑26a‑5p, miR‑22‑3p, miR‑16‑5p, let‑7b‑5p and let‑7c) had the potential to distinguish individuals with UTUC from the controls (areas under the curve >0.8). The present study provided the first evidence for the potential use of circulating miRNAs as biomarkers for UTUC diagnosis, which remains to be verified by further studies.

Distinct patterns and behaviour of urothelial carcinoma with respect to anatomical location: how molecular biomarkers can augment clinico-pathological predictors in upper urinary tract tumours

PURPOSE

Upper urinary tract urothelial carcinoma (UTUC) shares many similarities with bladder-UC, but there is strong evidence on a clinical, aetiological, epidemiological and genetic level that key differences exist. In this review, we aim to highlight how UTUC differs from bladder-UC and report on the utility of molecular markers in the diagnosis and management of UTUC.

MATERIALS AND METHODS

A systematic literature search was conducted using the Medline and Embase databases and specific keyword combinations: 'urothelial carcinoma', 'bladder cancer', 'transitional cell carcinoma', 'upper tract', 'upper urinary tract', 'genetics', 'prognosis' and 'biomarkers'.

RESULTS

UTUC has specific acquired (e.g. Balkans nephropathy, phenacetin abuse) and genetic hereditary non-polyposis colorectal cancer risk factors compared with bladder-UC. In general, the molecular biology of UC is broadly similar, irrespective of location in the urinary tract. However, there are distinct genetic (microsatellite instability) and epigenetic (hypermethylation) differences between some UTUC and bladder-UC. Clinical-pathological variables (e.g. hydronephrosis, tumour architecture, tumour location, stage and grade) have independent predictive power in UTUC, but tissue and urinary biomarkers can improve the clinical prediction of recurrence, invasion and survival in UTUC, though the evidence level is weak.

CONCLUSIONS

UTUC shares many similarities with bladder-UC, but there is strong evidence that they should be considered as distinct urothelial entities. Prospective multi-institutional studies investigating molecular markers are urgently needed to augment clinic-pathological predictors in UTUC.

Expression of p53 in upper urinary tract urothelial carcinoma

The management of upper urinary tract urothelial carcinoma (UUT-UC) is controversial. Radical nephroureterectomy is a major undertaking and has obvious shortcomings in the presence of renal impairment and solitary kidneys, whereas endoscopic management can be associated with a risk of disease progression. There is a pressing need for reliable predictive biomarkers to refine patient selection for renal conservation. p53 is the most frequently investigated molecular marker in UUT-UC. Of the 24 papers published on the subject, expression of p53 is a significant univariate prognostic marker in 12 publications, representing seven unique cohorts. However, multivariate analysis demonstrates that p53 expression is of independent prognostic significance in only five studies, all of which contain potential statistical bias. The currently available data do not, therefore, support a role for p53 in this regard, and suggest a need for prospective large-scale collaborative studies using standardized methods of p53 detection and statistical analysis.

Telomerase detection in the diagnosis and prognosis of cancer

Telomerase, a critical enzyme responsible 'for cellular immortality, is usually repressed in somatic cells except for lymphocytes and self-renewal cells, but is activated in approximately 85% of human cancer tissues. The human telomerase reverse transcriptase (hTERT) is the catalytic component of human telomerase. In cancers in which telomerase activation occurs at the early stages of the disease, telomerase activity and hTERT expression are useful markers for the detection of cancer cells. In other cancers in which telomerase becomes upregulated upon tumor progression, they are useful as prognostic indicators. However, careful attention should be paid to false-negative results caused by the instability of telomerase and of the hTERT mRNA and the presence of PCR inhibitors, as well as to false-positive results caused by the presence of alternatively spliced hTERT mRNA and normal cells with telomerase activity. Recently, methods for the in situ detection of the hTERT mRNA and protein have been developed. These methods should facilitate the unequivocal detection of cancer cells, even in tissues containing a background of normal telomerase-positive cells.

Prognostic factors for upper urinary tract urothelial carcinoma

Upper urinary tract urothelial carcinoma (UTUC) is a rare disease, which means there are little evidence-based data available to guide clinical decision-making. Although diagnosis and treatment of UTUC have improved significantly over the last 5 years, accurate risk stratification remains a challenge owing to the difficulty of clinical staging. A number of potential prognostic factors have been identified, encompassing clinical characteristics, pathological factors and molecular markers. Tumor stage and lymph node status are the most important predictors of survival in patients with UTUC. Preoperative evaluation for hydronephrosis can identify patients at risk of non-organ-confined disease. In the subgroup of patients with stage ≥pT2 disease, a longer interval between diagnosis and radical nephroureterectomy is associated with a higher risk of disease recurrence and cancer-specific mortality. Extensive tumor necrosis, sessile tumor architecture and lymphovascular invasion are independent predictors of clinical outcomes for patients with UTUC treated with radical nephroureterectomy. The incorporation of such prognosticators into clinical prediction models might help to guide decision-making with regard to timing of surveillance, type of treatment, performance of lymphadenectomy, and consideration of neoadjuvant or adjuvant systemic therapies.

Molecular and histological markers in urothelial carcinomas of the upper urinary tract

Urothelial cell carcinomas (UCCs) are one of the most common types of malignancies. Recently, different mechanisms of carcinogenesis, as well as discrepancies in the natural history of urothelial cancers of the bladder and of the upper urinary tract (UUT), have been identified. As a result several teams have focused on specific markers in UUT-UCCs, a very rare type of cancer. This review gives a brief overview on the current markers of interest. Microsatellite instabilities (MSI) are independent molecular makers for prognosis. In addition, MSI can help detect a germline mutation and therefore allows for the detection of possible hereditary cancers. The loss of proteins of the mismatch repair system can also facilitate the detection of a germline mutation but should be followed by DNA sequencing. Epithelial cadherin has been shown to be an independent marker of prognosis, as well as hypoxia-inducible factor-1alpha (HIF-1alpha) and telomerase RNA component. Furthermore HIF-1alpha is significantly associated with the grade and pattern of growth and the telomerase RNA component could possibly also be used in diagnosis. The active form of the L-type amino acid transporter 1 (LAT1) was a significant prognostic marker in univariate analysis only. There are contrasting studies on the significances of p27 and Ki-67 as prognostic markers in UUT-UCCs. MET is a factor that correlates with vascular invasion of invasive cancer and bcl-2 oncoprotein correlates with stage. The ongoing identification of these markers might help to find specific treatments tailored to the molecular pattern of each tumour. Therefore a subgroup of patients with a higher risk of recurrence could be identified as well as patients that could benefit from minimal invasive surgery.

Expressions of human telomerase mRNA component (hTERC) and telomerase reverse transcriptase (hTERT) mRNA in effusion cytology

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA onto chromosomal ends. Its activity has been reported to be a novel diagnostic marker of malignant potential. However, no study has investigated the diagnostic importance of the expressions of human telomerase mRNA component (hTERC) and telomerase reverse transcriptase (hTERT) mRNA in effusion cytology. We investigated the expressions of hTERC and hTERT using in situ hybridization in 20 malignant cytologic specimens from 20 patients with adenocarcinomas disseminating into the pleura or peritoneum, and 16 benign cytologic specimens in pleural or peritoneal fluid (including reactive mesothelial cells) from 16 patients with non-neoplastic diseases. Expressions of hTERC and hTERT mRNA were detected in 95% and 90% of the 20 malignant cytology specimens, respectively, and were apparent within the cytoplasm of malignant cells. However, no expression was detected in reactive mesothelial cells in the 16 benign cytologic specimens. The expressions of hTERC and hTERT mRNA would appear to be a useful addition to cytology examination for diagnosis based on effusion cytology.

Transitional cell carcinoma of the ureter and renal pelvis

Transitional cell carcinoma (TCC) of ureter and renal pelvis is relatively uncommon. Smoking, occupational carcinogens, analgesic abuse, Balkan nephropathy are the risk factors. Cytogenetic studies revealed that the most frequent aberration is the partial or complete loss of chromosome 9. Approximately 20-50% of patients with upper urinary tract (UUT) TCC have bladder cancer at some point on their course, whereas the incidence of UUT TCC after primary bladder cancer is 0.7-4%. Excretory urography and retrograde pyelography are the conventional diagnostic tools; however, ureteropyeloscopy combined with cytology and biopsy is more accurate. Grade and stage of the disease have the most significant impact on survival. Nephroureterectomy with bladder cuff excision has been the mainstay of treatment. Local resection may be appropriate for distal ureteral lesions especially when the disease is low grade and stage. Advances in endourology have made it possible to treat many tumors conservatively. Ureteroscopic and to a certain extent percutaneous surgical approaches are widely used today especially in patients with low grade, low stage disease. Endoscopic close surveillance is mandatory for these patients. Adjuvant topical therapies appear to be safe but confirmation of any benefits awaits the results of further large studies. More recently, laparoscopic techniques have become a viable alternative to open surgery, but long term cancer control data are lacking. Aggressive surgical resection does not affect the outcome of patients with advanced disease. Adjuvant radiotherapy is ineffective, and systemic chemotherapy results in a low complete response rate for patients with metastases.

Telomerase as tumor marker

Telomerase, a critical enzyme responsible for continuous cell growth, is repressed in most somatic cells except proliferating progenitor cells and activated lymphocytes, and activated in approximately 85% of human cancer tissues. Telomerase activity is a useful cancer-cell detecting marker in some types of cancers in which almost all cases show telomerase activation. In other types in which telomerase becomes upregulated according to tumor progression, it is a useful prognostic indicator. Detection of human telomerase reverse transcriptase (hTERT) mRNA or protein in various clinical samples is also applicable. However, careful attention should be paid to the false negative results due to the instability of this enzyme or hTERT mRNA and the existence of polymerase chain reaction inhibitors as well as the false-positive results due to the contamination by normal cells with telomerase activity. If these pitfalls are avoided, in situ detection of hTERT mRNA or protein will facilitate the reliability of telomerase as a tumor marker.

Expression of telomerase catalytic subunit (hTERT) mRNA does not predict survival in patients with transitional cell carcinoma of the upper urinary tract

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric repeats onto chromosomal ends using a segment of its RNA component as a template. Its activity has become an established indicator of the diagnosis, biological behavior, and prognosis of several tumors. However, few studies have investigated the diagnostic and prognostic importance of the expression of telomerase catalytic subunit (hTERT) mRNA in transitional cell carcinoma of the upper urinary tract (TCC-UUT). We investigated the expression of hTERT mRNA using in situ hybridization in 125 cases of TCC-UUT, and also its relation with the expression of telomerase RNA component (hTERC), proliferating cell nuclear antigen (PCNA) immunoreactivity, clinicopathologic parameters, and clinical outcome. A positive expression of hTERT mRNA was recognized in 93.6% of the samples and was apparent within the cytoplasm of tumor cells. In the normal urothelium examined in a few cases, its expression was barely detected. hTERT mRNA scores showed a significant association with hTERC score. However, no relationship was found between the expression of hTERT mRNA and clinicopathologic findings, PCNA index, or prognosis. These results suggest that the expression of hTERT mRNA does not predict prognosis in TCC-UUT.

Telomerase activity and expression of human telomerase RNA component and human telomerase reverse transcriptase in lung carcinomas

The aim of this study was to evaluate the usefulness of determination of telomerase activity and expression of human telomerase RNA component (hTERC) and human telomerase reverse transcriptase (hTERT) for the diagnosis of lung carcinomas. The tissues studied consisted of 115 carcinomas and adjacent nonneoplastic lung, which were removed surgically without previous chemotherapy or radiotherapy. Telomerase activity was determined using a semiquantitative polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay. The results obtained were classified into high and low telomerase groups. Localization of expression was examined by using in situ hybridization and immunohistochemistry. The correlation between telomerase activity in lung carcinoma and clinicopathologic features, including prognosis, was investigated. Telomerase activity in lung carcinomas was detected in 107 of 115 (93%) lung carcinomas, but not in any adjacent noncancerous tissues, and was significantly higher in small cell carcinoma than in any other histologic type. This activity also was significantly higher in poorly differentiated than in well-differentiated squamous cell carcinomas and adenocarcinomas. The overall survival rate (P =.020) was significantly lower in the high telomerase group. Messenger RNAs for hTERC and hTERT were mainly detected in the cytoplasm of cancer cells by in situ hybridization, and TERT protein was localized in the nuclei of these cells by immunohistochemical staining. Determinations of telomerase activity by in situ hybridization, immunohistochemistry, and TRAP assay are useful for evaluating the diagnosis and prognosis of lung carcinomas.

PCR and in situ hybridization studies of telomerase subunits in human non-neoplastic livers

Telomerase, a ribonucleoprotein enzyme associated with cellular immortality, consists of human telomerase RNA component (hTERC), human telomerase protein 1 (hTEP1), and human telomerase reverse transcriptase (hTERT). In this study, the expression of these subunits was examined in non-neoplastic livers [13 cases of chronic viral hepatitis (CVH), 16 of primary biliary cirrhosis (PBC), two of primary sclerosing cholangitis, and six normal livers], using the reverse transcription-polymerase chain reaction (RT-PCR), nested PCR, and in situ hybridization (ISH). Six hepatocellular carcinoma (HCC) cases and one colonic cancer were used as positive controls. Telomeric repeat amplification protocol (TRAP) assay disclosed distinct telomerase activity in all positive controls and weak telomerase activity in non-neoplastic livers in 4 of 13 CVH cases and 5 of 16 PBC cases. By RT- and nested PCR, both hTERC and hTEP1 mRNA were detectable in all non-neoplastic liver tissues; ISH revealed hTERC and hTEP1 mRNA in the periportal and periseptal hepatocytes and inflammatory mononuclear cells in those cases examined. ISH revealed hTERT mRNA only in a few infiltrating mononuclear cells in 3 of 13 CVH and 2 of 16 PBC livers and these five cases were also positive by TRAP assay. In four of these five cases, hTERT mRNA was also detectable by nested PCR, suggesting that hTERT mRNA in the non-neoplastic liver is expressed by infiltrating mononuclear cells. Biliary epithelial cells were totally negative for these human telomerase subunits. Three subunits were constantly detected in all positive controls by ISH as well as by RT- and nested PCR. The finding that hTERC and hTEP1 mRNA, but not hTERT mRNA, were detectable in the non-neoplastic hepatocytes suggests that telomerase is present but not activated and that additional factor(s) are necessary for the expression of hTERT mRNA in the hepatocytes, along with immortalization and neoplastic transformation.

Overexpression of human telomerase RNA in Helicobacter pylori-infected human gastric mucosa

Telomerase, an enzyme associated with cellular immortality and malignancy, plays an important role in cellular immortalization and tumorigenesis. Furthermore, overexpression of the RNA component of the telomerase, called human telomerase RNA (hTR), has been demonstrated in various human cancers as an early event. The pattern of hTR expression following Helicobacter pylori (H. pylori) infection in human gastric mucosa was investigated by a radioactive in situ hybridization (ISH) assay. Paraffin-embedded sections of 50 biopsy specimens taken from the gastric antrum of individual patients infected to different extents with H. pylori, as well as normal gastric mucosa, were studied. In normal gastric mucosa, only weak hTR expression was noted and the expression was limited to basal cells of the gastric glands. However, the degree of hTR expression gradually increased in parallel with the degree of H. pylori infection. The mean scores of gastric mucosa with mild, moderate and severe degrees of H. pylori infection were 2.3, 2.8, and 3.7 times higher than that of normal gastric mucosa, respectively. The results of this study suggested that up-regulation of hTR expression is a frequent and early event associated with H. pylori infection in the gastric mucosa and may play some role in gastric carcinogenesis. Sufficient synthesis of hTR during this early stage may be a prerequisite for telomerase reactivation to occur in gastric cancer.