Catalytic Subunit of Human Telomerase Reverse Transcriptase Is an Independent Predictor of Survival in Patients Undergoing Curative Resection of Hepatic Colorectal Metastases: A Multicenter Analysis

A Review of Telomere Attrition in Cancer and Aging: Current Molecular Insights and Future Therapeutic Approaches

BACKGROUND/OBJECTIVES

As cells divide, telomeres shorten through a phenomenon known as telomere attrition, which leads to unavoidable senescence of cells. Unprotected DNA exponentially increases the odds of mutations, which can evolve into premature aging disorders and tumorigenesis. There has been growing academic and clinical interest in exploring this duality and developing optimal therapeutic strategies to combat telomere attrition in aging and cellular immortality in cancer. The purpose of this review is to provide an updated overview of telomere biology and therapeutic tactics to address aging and cancer.

METHODS

We used the Rayyan platform to review the PubMed database and examined the ClinicalTrial.gov registry to gain insight into clinical trials and their results.

RESULTS

Cancer cells activate telomerase or utilize alternative lengthening of telomeres to escape telomere shortening, leading to near immortality. Contrarily, normal cells experience telomeric erosion, contributing to premature aging disorders, such as Werner syndrome and Hutchinson-Gilford Progeria, and (2) aging-related diseases, such as neurodegenerative and cardiovascular diseases.

CONCLUSIONS

The literature presents several promising therapeutic approaches to potentially balance telomere maintenance in aging and shortening in cancer. This review highlights gaps in knowledge and points to the potential of these optimal interventions in preclinical and clinical studies to inform future research in cancer and aging.

SPT6 recruits SND1 to co-activate human telomerase reverse transcriptase to promote colon cancer progression

Human telomerase reverse transcriptase (hTERT) plays an extremely important role in cancer initiation and development, including colorectal cancer (CRC). However, the precise upstream regulatory mechanisms of hTERT in different cancer types remain poorly understood. Here, we uncovered the candidate transcriptional factor of hTERT in CRC and explored its role and the corresponding molecular mechanisms in regulating hTERT expression and CRC survival with an aim of developing mechanism-based combinational targeting therapy. The possible binding proteins at the hTERT promoter were uncovered using pull-down/mass spectrometry analysis. The regulation of SPT6 on hTERT expression and CRC survival was evaluated in human CRC cell lines and mouse models. Mechanistic studies focusing on the synergy between SPT6 and staphylococcal nuclease and Tudor domain containing 1 (SND1) in controlling hTERT expression and CRC progression were conducted also in the above two levels. The expression correlation and clinical significance of SPT6, SND1, and hTERT were investigated in tumor tissues from murine models and patients with CRC in situ. SPT6 was identified as a possible transcriptional factor to bind to the hTERT promoter. SPT6 knockdown decreased the activity of hTERT promoter, downregulated the protein expression level of hTERT, suppressed proliferation, invasion, and stem-like properties, promoted apoptosis induction, and enhanced chemotherapeutic drug sensitivity in vitro. SPT6 silencing also led to the delay of tumor growth and metastasis in mice carrying xenografts of human-derived colon cancer cells. Mechanistically, SND1 interacted with SPT6 to co-control hTERT expression and CRC cell proliferation, stemness, and growth in vitro and in vivo. SPT6, SND1, and hTERT were highly expressed simultaneously in CRC tissues, both from the murine model and patients with CRC in situ, and pairwise expression among these three factors showed a significant positive correlation. In brief, our research demonstrated that SPT6 synergized with SND1 to promote CRC development by targeting hTERT and put forward that inhibiting the SPT6-SND1-hTERT axis may create a therapeutic vulnerability in CRC.

Human telomerase reverse transcriptase recruits the β-catenin/TCF-4 complex to transactivate chemokine (C-C motif) ligand 2 expression in colorectal cancer

BACKGROUND AND AIM

Various molecular mechanisms are involved in the pathogenesis of colorectal cancer (CRC), one of the leading fatal diseases. Although human telomerase reverse transcriptase (hTERT) is critical in promoting CRC development, its regulatory mechanism is still elusive. Chemokine (C-C motif) ligand 2 (CCL2) is important to CRC pathogenesis, but the upstream regulation of CCL2 requires further investigation. Therefore, we aim to investigate the crosstalk mechanism between hTERT and CCL2 and its involvement in the pathogenesis of CRC.

METHODS

The expression relationship between hTERT and CCL2 was verified in CRC and adjacent tissues by immunohistochemistry. Lentiviruses or plasmids were used to regulate hTERT and CCL2 expression. The roles of hTERT and CCL2 in cell growth and migration were studied using CCK8 and transwell assays. The interaction between hTERT and CCL2 was detected by a luciferase reporter assay, immunofluorescence and ChIP assays. The β-catenin/TCF-4 complex was confirmed by COIP.

RESULTS

Both hTERT and CCL2 expression levels were markedly increased in CRC tissues compared to the adjacent stroma. Moreover, myeloid-derived suppressor cells (MDSCs) were found in tumor areas with higher expression levels of hTERT and CCL2. hTERT promoted HCT116 cell migration and invasion by increasing CCL2 expression. Mechanistically, ectopic hTERT facilitated the nuclear translocation of canonical β-catenin and the formation of a complex with downstream effector TCF-4, which eventually activated the CCL2 promoter.

CONCLUSIONS

hTERT may promote CRC by recruiting β-catenin/TCF-4 complex to transactivate CCL2 expression, which is a novel crosstalk mechanism likely involved in the pathogenesis of CRC.

Immunohistochemical investigation of prognostic biomarkers in resected colorectal liver metastases: a systematic review and meta-analysis

BACKGROUND

Many studies have investigated the prognostic role of biomarkers in colorectal liver metastases (CRLM). However, no biomarker has been established in routine clinical practice. The aim of this study was to scrutinize the current literature for biomarkers evaluated by immunohistochemistry as prognostic markers in patients with resected CRLM.

METHODS

A systematic review was performed according to the PRISMA guidelines. Articles were identified in the PubMed database with selected search terms and by cross-references search. The REMARK quality criteria were applied. Markers were included if they reported the prognostic impact of immunohistochemical markers in a multivariable setting in relation to overall survival (OS). A meta-analysis was conducted when more than one original article provided survival data of a marker.

RESULTS

In total, 26 biomarkers were identified as independent significant markers for OS in resected CRLM. These biomarkers were found to be involved in multiple oncogenic signalling pathways that control cell growth, apoptosis, angiogenesis and evasion of immune detection. Among these biomarker candidates were Ki-67, EGFR, p53, hTERT, CD34, TSP-1, KISS1, Aurora kinase A and CDX2. CD34 and TSP-1 were reported as significantly associated with survival by more than one study and where therefore pooled in a meta-analysis.

CONCLUSION

A number of independent prognostic biomarkers for resected CRLM were identified. However, most markers were evaluated in a retrospective setting with small patient cohorts, without external validation. Large, prospective, multicentre studies with standardised methods are needed before biomarkers can translated into the clinic.

Phase I trial of intravenous Ad5CRT in patients with liver metastasis of gastrointestinal cancers

We conducted a phase 1 trial for single-dose intravenous Ad5CRT, a replication-defective adenovirus vector expressing HSVtk (herpes simplex virus thymidine kinase) modulated by a specific trans-splicing ribozyme that targets human telomerase reverse transcriptase (hTERT)-encoding RNAs. Dose-limiting toxicities (DLTs) were evaluated in 15 patients at dose levels of 0.1-2 × 10¹² virus particles. Patients well tolerated study treatment. During the DLT evaluation period, none of the 15 patients developed any grade 4 toxicities or treatment discontinuation that was related to agents investigated by this trial. The most frequent treatment-related adverse event was fever/chill (26.7%). Of the 18 patients, no patients achieved a partial or complete response, and the median progression-free survival for 18 patients was 1.1 months (95% CI, 1.0-1.3) and the results suggest no clinical benefit from this treatment. Ad5CRT's circulating virus half-life was approximately 10 min. Maximum tolerated dose was 2 × 10¹² virus particles. Single-dose intravenous Ad5CRT was feasible and well tolerated in patients with gastrointestinal cancer liver metastasis. Ad5CRT did not provide meaningful clinical benefit, and the reason for the lack of efficacy was not entirely clear because no pharmocodynamic assessment was made.

The prognostic significance of hTERT overexpression in cancers: A systematic review and meta-analysis

BACKGROUND

Human telomerase reverse transcriptase (hTERT) plays an important role in cancer progression. Recently, several clinical studies investigated how the overexpression of hTERT predicts the poor prognosis of solid tumors. However, the results were inconclusive, partly because of the small numbers of patients included.

METHOD

We systematically searched PubMed, Web of Science, and Embase to identify relevant studies until August 2017. Hazard ratios (HRs) with 95% confidence intervals (CIs) were used to evaluate the association of hTERT expression and survival outcomes.

RESULTS

A total of 27studies enrolling 2530 solid tumor patients were included in this meta-analysis. There were strong significant associations between hTERT overexpression and all endpoints: overall survival (OS) (HR = 1.50, 95% CI: 1.31-1.73, P = .00), disease-free survival (HR = 1.84, 95% CI: 1.38-2.46; P = .00), and recurrence-free survival (HR = 1.79, 95% CI: 1.07-2.99; P = .028). In the subgroup analysis, it was found that the overexpression of hTERT induced poor OS in lung cancer (HR = 1.51, 95% CI: 1.21-1.89; P = .00).

CONCLUSION

Our comprehensive systematic review concluded that the overexpression of hTERT was associated with poor survival in human solid tumors. hTERT may be a valuable predictive biomarker for prognosis.

Telomerase reverse transcriptase interference synergistically promotes tumor necrosis factor‑related apoptosis‑inducing ligand‑induced oral squamous cell carcinoma apoptosis and suppresses proliferation in vitro and in vivo

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is known to induce cell apoptosis in many types of cancer cells. However, some malignant cells still exhibit anti-apoptosis features induced by TRAIL; thus the underlying mechanisms that regulate sensitivity and resistance of tumor cells to TRAIL-induced apoptosis remain unclear. Human telomerase reverse transcriptase (hTERT) is overexpressed in most types of human tumors and is mostly inactive in somatic cells. The present study aimed to investigate the endogenous effects and mechanisms of hTERT inhibition and TRAIL overexpression on TRAIL-induced apoptosis of human oral squamous cell carcinoma (OSCC) cells. The effects of adeno-associated virus (AAV)-mediated TRAIL and hTERT gene silencing by RNA interference were investigated on the proliferation and apoptosis of human OSCC cells in vitro and in vivo. The present results suggest that knockdown of hTERT expression accelerated TRAIL-resistant OSCC cells to TRAIL-induced apoptosis and impaired OSCC cell proliferation. In addition, this process is accompanied by the upregulation of caspase-3, caspase-8 and caspase-9, and downregulation of B cell lymphoma-2. Additionally, the possible mechanisms underlying the association between TRAIL expression and hTERT silencing were explored. The results demonstrated that TRAIL expression levels were elevated when the hTERT gene was silenced, and notable anti-tumor effects were observed when TRAIL upregulation and hTERT gene silencing were carried out simultaneously. The present findings provide experimental evidence for the combined use of TRAIL and hTERT as a possible gene therapy strategy in oral cancer.

Survival time and prognostic factors of patients with initial noncurative colorectal liver metastases

The true survival benefit of different curative strategies involving type of operative procedure and timing for patients with initial noncurative colorectal liver metastases remains uncertain. The goal of this study was to examine the effect of primary tumor resection on patients' survival and to clarify the predictive factors related to overall survival (OS).This was a retrospective study that included 219 patients with initial noncurative colorectal liver metastases without extrahepatic disease. The clinicopathological characteristics of patients and their survival were examined. Survival analysis was performed using the Kaplan-Meier method. All variables associated with P <.05 in univariate analysis were included in multivariate analysis using a Cox proportional-hazard regression model.The 1-, 3-, 5-year OS rates of patients with simultaneous liver resection were 79.1%, 39.1%, and 28.4%, respectively, and those of patients with staged liver resection were 83.3%, 46.7%, and 36.8%, respectively (P = .380). The 1-, 3-, 5-year OS rates of patients with primary tumor resection were 57.0%, 18.2%, and 12.3%, respectively, while for the patients without primary tumor resection were 38.9%, 5.6%, and 0%, respectively (P = .012). Independent prognostic factors for OS were carbohydrate antigen19-9, primary tumor resection, tumor differentiation, and adjuvant chemotherapy.No difference in OS was observed between simultaneous liver resection and staged liver resection, while primary tumor resection was beneficial to noncurative colorectal liver metastases.

TERT Promoter Hypermethylation in Gastrointestinal Cancer: A Potential Stool Biomarker

BACKGROUND

There is a high demand for noninvasive screening tools for gastrointestinal cancer (GIC) detection, and GIC-specific markers are required for such purposes. It is established that induction of the telomerase reverse transcriptase gene (TERT) coupled with telomerase activation is essential for cancer development/progression and aberrant TERT promoter methylation of specific 5'-C-phosphate-G-3' (CpGs) has been linked to TERT induction in oncogenesis. Here we analyzed TERT promoter methylation in fecal samples from GIC patients and healthy adults and determined its value as a stool biomarker for GIC detection.

MATERIALS AND METHODS

Sixty-nine GIC patients (34 colorectal carcinoma and 35 gastric cancer) and 62 healthy adults were recruited and fecal samples were collected. Paired tumors and adjacent non-cancerous tissues from 34 patients and normal mucosa tissues from 12 healthy individuals were collected. TERT promoter methylation density was determined using pyrosequencing.

RESULTS

We identified two GIC-specific methylation sites at -218 (CpG site 1) and -210 (CpG site 2) in the TERT promoter in tumor tissues. Methylated TERT promoter CpG sites 1 and 2 were also detectable in patient stool, while only background levels were observed in healthy individuals. The overall sensitivity reached 52.2% (95% confidence interval [CI]: 48.3-56.0) for fecal methylated TERT promoter assays at 90% specificity, which was comparable to other known stool methylation markers for GIC detection. The combined assays of fecal TERT promoter methylation and occult blood (OB) significantly improved sensitivity and specificity in colorectal cancer (area under curves for methylation alone: 0.798, 95% CI: 0.707-0.889 vs. methylation + OB: 0.920, 95% CI: 0.859-0.981; p = .028), but not in gastric cancer.

CONCLUSION

This proof-of-concept study suggests the feasibility of stool TERT promoter methylation analyses as an additional tool in noninvasive GIC screening.

IMPLICATIONS FOR PRACTICE

Induction of telomerase reverse transcriptase (TERT) expression coupled with telomerase activation is essential for cancer development/progression, while aberrant TERT promoter methylation has been linked to TERT induction in oncogenesis. We identified two cancer-specific methylation sites (CpG1 and 2) in the TERT promoter in tumors from GIC patients. Methylated TERT promoter CpG sites 1 and 2 were detectable in patient stool, while only background levels were observed in healthy individuals. The sensitivity and specificity was comparable to other known stool methylation markers for GIC detection. This proof-of-concept study suggests the feasibility of stool TERT promoter methylation analyses for noninvasive screening of GIC.

TERT promoter mutations in renal cell carcinomas and upper tract urothelial carcinomas

TERT promoter mutations are identified in many malignancies including bladder cancer (BC) and upper tract urothelial carcinoma (UTUC). In contrast, no mutations were found in renal cell carcinoma (RCC) as reported in a recent study. Because the mutant TERT promoter in urine DNA was recently tested as a marker for BC, it is important to ascertain whether these mutations are truly absent in RCCs. Here we determined TERT promoter mutations in 109 patients with RCC and 14 patients with UTUC. The mutations were found in 9/96 (9.3%) clear cell RCC (ccRCC) tumors and 1/8 (13%) chromophobe RCC tumors. Among ccRCC patients, the mutation was correlated with the advanced stages and metastasis, and higher TERT expression. Among UTUCs, the mutation was detected in tumors from 3/5 (60%) patients with renal pelvic cancer and 1/9 (11%) patients with ureter cancer. The mutation was also detected in 1 of 4 urine samples from patients with mutation+ UTUC. Collectively, TERT promoter mutations do occur in RCCs and are associated with aggressive disease. The mutation is more frequent in renal pelvic cancer. Thus, the mutant TERT promoter found in urine may come from not only BC, but also RCC or UTUC.

High expression of hTERT and stemness genes in BORIS/CTCFL positive cells isolated from embryonic cancer cells

BORIS/CTCFL is a member of cancer testis antigen family normally expressed in germ cells. In tumors, it is aberrantly expressed although its functions are not completely well-defined. To better understand the functions of BORIS in cancer, we selected the embryonic cancer cells as a model. Using a molecular beacon, which specifically targets BORIS mRNA, we demonstrated that BORIS positive cells are a small subpopulation of tumor cells (3–5% of total). The BORIS-positive cells isolated using BORIS-molecular beacon, expressed higher telomerase hTERT, stem cell (NANOG, OCT4, SOX2) and cancer stem cell marker genes (CD44 and ALDH1) compared to the BORIS-negative tumor cells. In order to define the functional role of BORIS, stable BORIS-depleted embryonic cancer cells were generated. BORIS silencing strongly down-regulated the expression of hTERT, stem cell and cancer stem cell marker genes. Moreover, the BORIS knockdown increased cellular senescence in embryonic cancer cells, revealing a putative role of BORIS in the senescence biological program. Our data indicate an association of BORIS expressing cells subpopulation with the expression of stemness genes, highlighting the critical role played by BORIS in embryonic neoplastic disease.

SMAD4 and TS expression might predict the risk of recurrence after resection of colorectal liver metastases

PURPOSE

Colorectal liver metastases (CLM) have significant molecular heterogeneity, which contributes to the risk of recurrence following surgery. Most of the traditional scores intended to predict recurrence is based on clinicopathological variables and it is unclear whether incorporating molecular biomarkers might improve our assessment of the risk of recurrence. Our aim was to determine if molecular biomarkers might be associated with the risk of recurrence after surgery of CLM.

PATIENTS AND METHODS

A total of 121 patients diagnosed with colorectal cancer (CRC) with resected liver metastases were included. The role of several clinicopathological variables to predict patient's outcome after resection of liver metastases was analyzed. Eighteen genes related to CRC pathogenesis were also included in the analyses. Univariate and multivariate stepwise Cox regression analyses were performed to identify factors associated with recurrence and the risk of death.

RESULTS

Eight prognostic factors for progression-free survival and nine factors for overall survival were identified in the univariate analyses. After adjusting for other risk factors, only the expression of two molecular factors was associated with the risk of recurrence: TS (HR 0.631, 95 % CI 0.422-0.944) and SMAD4 (HR 1.680, 95 % CI 1.047-2.695). None of the variables was significantly associated with the risk of death in the multivariate analyses.

CONCLUSIONS

The prognostic significance of most traditional clinicopathological variables might be insufficient to define patients at risk for recurrence after liver metastases resection. Molecular biomarkers might improve the identification of patients with higher risk of recurrence.

Surgery for colorectal liver metastases: The evolution of determining prognosis

Despite improvements in the multi-modality treatment of colorectal liver metastasis (CRLM), survival after resection remains varied. Determining prognosis after surgical resection has historically been predicated on preoperative clinicopathological factors such as primary tumor stage, carcinoembryonic antigen levels, number of liver metastases, presence of extrahepatic disease, as well as other factors. While scoring systems have been developed by combining certain preoperative factors, these have been inconsistent in accurately determining prognosis. There has been increasing interest in the use of biologic and molecular markers to predict prognosis following CRLM. The role of markers such as KRAS, BRAF, p53, human telomerase reverse transcriptase, thymidylate synthase, Ki-67, and hypoxia inducible factor-1α and their correlation with accurately predicting survival after surgical resection have been supported by several studies. Furthermore, other elements such as pathological response to chemotherapy and the presence of circulating tumor cells have shown promise in accurately determining prognosis after resection for colorectal liver metastasis. We herein review past, present, and possible future markers of prognosis among colorectal cancer patients with liver metastasis undergoing resection with curative intent.

Prognostic factors after resection of colorectal liver metastases: from morphology to biology

Despite improved overall survival rates after potentially curative liver resection (~50-58% at 5 years), almost half of patients experience disease recurrence highlighting the need for a precise definition of outcomes to stratify patients for clinical trials and to guide treatment decisions. In the past, several factors, such as an advanced primary T stage, the primary N+ status, a large tumor size, multiple tumors, a disease-free interval of <12 months, an elevated carcinoembryonic antigen level, the presence of an extrahepatic disease, and the margin width (<1 cm) and status (positive), have been recognized to predict poor outcomes, but most of them lack the sensitivity for accurate individual prognostication. Thus, in recent years, new factors, such as response to chemotherapy, either clinical or pathological, that more closely reflect tumor biology have been established and adopted in the clinical practice. Similarly, biomarkers of poor prognosis, especially mutations in KRAS and BRAF and the expression of thymidylate synthase, have been studied, yielding promising results. However, robust evidence of their prognostic utility awaits prospective validation.

Implications of telomere-independent activities of telomerase reverse transcriptase in human cancer

Telomerase plays a pivotal role in the pathology of cancer by maintaining genome integrity, controlling cell proliferation, and regulating tissue homeostasis. Experimental data from genetically modified mice and human premature aging diseases clearly indicate that intact telomere function is crucial for cell proliferation and survival, whereas dysfunctional telomeres can lead to either cancer or aging pathologies, depending on the integrity of the cellular stress response pathways. The canonical function of telomerase reverse transcriptase is the synthesis of telomeric DNA repeats and the maintenance of telomere length. However, accumulating evidence indicates that telomerase reverse transcriptase may also exert some fundamental biological functions independently of its enzymatic activity in telomere maintenance. More recent studies have demonstrated that telomerase reverse transcriptase can act as a transcriptional modulator in the nucleus and exhibits RNA-dependent RNA polymerase activity in the mitochondria. Telomerase activation may have both telomere-dependent and telomere-independent implications for tumor progression. Many excellent reviews have described critical roles of telomere and telomerase in human cancer; this minireview will focus on the role of telomerase in cancer progression, with a special emphasis on the nontelomeric function of telomerase.

Telomerase reverse transcriptase promotes epithelial-mesenchymal transition and stem cell-like traits in cancer cells

Telomerase activation through induction of telomerase reverse transcriptase (hTERT) contributes to malignant transformation by stabilizing telomeres. Clinical studies demonstrate that higher hTERT expression is associated with cancer progression and poor outcomes, but the underlying mechanism is unclear. Because epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) are key factors in cancer metastasis and relapse, and hTERT has been shown to exhibit multiple biological activities independently of its telomere-lengthening function, we address a potential role of hTERT in EMT and CSCs using gastric cancer (GC) as a model. hTERT overexpression promotes, whereas its inhibition suppresses, EMT and stemness of GC cells, respectively. Transforming growth factor (TGF)-β1 and β-catenin-mediated EMT was abolished by small interfering RNA depletion of hTERT expression. hTERT interacts with β-catenin, enhances its nuclear localization and transcriptional activity, and occupies the β-catenin target vimentin promoter. All these hTERT effects were independent of its telomere-lengthening function or telomerase activity. hTERT and EMT marker expression correlates positively in GC samples. Mouse experiments demonstrate the in vivo stimulation of hTERT on cancer cell colonization. Collectively, hTERT stimulates EMT and induces stemness of cancer cells, thereby promoting cancer metastasis and recurrence. Thus, targeting hTERT may prevent cancer progression by inhibiting EMT and CSCs.

Management of colorectal cancer patients after resection of liver metastases: can we offer a tailored treatment?

Surgical resection remains the only option of cure for patients with colorectal liver metastases, and no patient should be precluded from surgery. There is much controversy not only regarding the most appropriate therapeutic approach in the neoadjuvant setting but also after surgery is performed. Many patients will experience early relapses but others will be long survivors. We need to establish reliable prognostic and predictive factors to offer a tailored treatment. Several prognostic factors after metastasectomy have been identified: high C-reactive protein levels, a high neutrophil-lymphocyte ratio, elevated neutrophil count and low serum albumin are related to a worst outcome. Elevated CEA and Ki 67 levels, intrahepatic and perihepatic lymph node invasion are also some of the markers related to a worst outcome. In contrast, the administration of preoperative chemotherapy has been associated with a better prognosis after hepatectomy. The administration of adjuvant chemotherapy should be done taking in consideration these factors. Regarding predictive factors, determination of ERCC1, TS, TP and DPD and UGT1 polymorphisms assessment could be considered prior to chemotherapy administration. This would avoid treatment related toxicities and increase this population quality of life.

Pathologic response to bevacizumab-containing chemotherapy in patients with colorectal liver metastases and its correlation with survival

For patients with colorectal liver metastases (CLM), hepatic resection currently offers the best chance for long-term survival. Preoperative chemotherapy is now integral to the management of these patients, conferring a disease-free survival advantage over surgery alone in patients with 'upfront' resectable disease and enabling some initially unresectable CLM to become resectable. However, although surgery may improve long-term survival, up to 65.0% of patients will experience disease recurrence at 5 years and reliable prognostic factors are needed to predict those patients who are more likely to experience recurrence after resection. Recently, pathologic tumor response, defined as the 'objective measurement of residual cancer cells in resected tissue,' has been identified as a reliable prognostic factor in patients with colorectal cancer (CRC) receiving preoperative chemotherapy and has been shown to correlate with improved survival after resection of CLM. Addition of the targeted biologic agent bevacizumab to preoperative chemotherapy is associated with an increase in pathologic response rate and an increase in survival compared with chemotherapy alone in patients undergoing hepatic resection. This review discusses the data in support of pathologic response rate as an important new outcome endpoint after hepatic resection of CLM and considers the evidence to date on pathologic response to bevacizumab-containing chemotherapy in metastatic CRC and its correlation with survival.

High levels of nucleolar expression of nucleolin are associated with better prognosis in patients with stage II pancreatic ductal adenocarcinoma

PURPOSE

Nucleolin is a major nucleolar protein that has been shown to be overexpressed in rapidly dividing cells and plays an essential role in cell proliferation and survival. However, the expression and significance of nucleolin in pancreatic ductal adenocarcinoma (PDA) have not been studied.

EXPERIMENTAL DESIGN

We used a tissue microarray consisting of 1.0-mm cores of tumor and paired nonneoplastic pancreatic tissue from 69 pancreaticoduodenectomy specimens with stage II PDA. Nucleolin expression was evaluated by immunohistochemistry and scored quantitatively by image analysis. Nucleolin expression was classified as nucleolin-high or nucleolin-low using the median nucleolin labeling index of 3.5% as cutoff. Staining results were correlated with clinicopathologic features and survival.

RESULTS

Both PDAs and PDA cell lines showed nucleolar staining for nucleolin. Nucleolin expression was higher in PDAs and PDA cell lines than in nonneoplastic ductal epithelial cells. Among the 69 stage II PDAs, 34 (49%) were nucleolin-high. The median overall survival was 65.2 +/- 16.3 months for patients who had nucleolin-high PDAs compared with 19.5 +/- 3.3 months for patients whose tumors were nucleolin-low (P = 0.03, log-rank method). No significant correlation between nucleolin expression and other clinicopathologic parameters was found. In multivariate analysis, nucleolin expression was a prognostic factor for overall survival in patients with stage II PDA independent of patient's age, gender, tumor size, differentiation, and lymph node status.

CONCLUSIONS

Nucleolin was overexpressed in PDAs and PDA cell lines. A high level of nucleolar expression of nucleolin was an independent prognostic marker for better survival for patients with stage II PDAs.

Lapatinib

The human epidermal growth factor receptor (HER) family of growth factor receptor tyrosine kinases (RTKs) plays an important role in the biology of many cancers. In breast cancer, HER2 and its homo- or heterodimerization with HER1 or HER3 are essential for cancer cell growth and survival. Patients overexpressing HER2 have a poor prognosis, which can be substantially improved upon HER2-targeted therapy using the monoclonal antibody trastuzumab. Lapatinib is a novel dual tyrosine kinase inhibitor, blocking HER1 and HER2 tyrosine kinase activity by binding to the ATP-binding site of the receptor's intracellular domain. This results in inhibition of tumor cell growth. The drug is relatively well tolerated in patients, with few and mostly low-grade adverse effects. In particular and unlike to trastuzumab, it has very little, if any, adverse effects on cardiac function. In patients with advanced HER2-positive breast cancer, lapatinib has shown substantial antitumor activity, particularly in combination with capecitabine upon progressive disease following standard therapy with antracyclines, taxanes, and trastuzumab. Ongoing and future studies will explore its role in the adjuvant therapy setting, in drug combinations other than capecitabine, and in the treatment of HER2-positive tumors other than breast cancer.

Tissue biomarker development in a multicentre trial context: a feasibility study on the PETACC3 stage II and III colon cancer adjuvant treatment trial

PURPOSE

We evaluated the feasibility of biomarker development in the context of multicenter clinical trials.

EXPERIMENTAL DESIGN

Formalin-fixed, paraffin-embedded (FFPE) tissue samples were collected from a prospective adjuvant colon cancer trial (PETACC3). DNA was isolated from tumor as well as normal tissue and used for analysis of microsatellite instability, KRAS and BRAF genotyping, UGT1A1 genotyping, and loss of heterozygosity of 18 q loci. Immunohistochemistry was used to test expression of TERT, SMAD4, p53, and TYMS. Messenger RNA was retrieved and tested for use in expression profiling experiments.

RESULTS

Of the 3,278 patients entered in the study, FFPE blocks were obtained from 1,564 patients coming from 368 different centers in 31 countries. In over 95% of the samples, genomic DNA tests yielded a reliable result. Of the immmunohistochemical tests, p53 and SMAD4 staining did best with reliable results in over 85% of the cases. TERT was the most problematic test with 46% of failures, mostly due to insufficient tissue processing quality. Good quality mRNA was obtained, usable in expression profiling experiments.

CONCLUSIONS

Prospective clinical trials can be used as framework for biomarker development using routinely processed FFPE tissues. Our results support the notion that as a rule, translational studies based on FFPE should be included in prospective clinical trials.

Current management of colorectal hepatic metastasis

In the USA, cancers of the colon and rectum are the third most common site of new cancer cases and cancer deaths. With improved screening and adjuvant therapy, the survival of patients has increased substantially over the last decade. However, patients with metastatic disease often have limited survival. Hepatic metastasis is one of the most frequent sites of metastatic disease. In fact, 35-55% of patients with colorectal cancer will develop hepatic metastasis at some time during the course of their disease. Patients who are able to undergo complete resection of their hepatic metastases have the best chance of long-term survival. The goal of hepatic resection is to achieve complete resection of all metastases with microscopically negative surgical margins while preserving sufficient hepatic parenchyma. Survival following hepatic resection of colorectal metastasis now approaches 35-50%. However, approximately 65% of patients will have a recurrence at 5 years. Increasingly chemotherapeutic agents are being offered in the preoperative setting prior to operation. At the time of operation, patients with extensive hepatic disease can sometimes be offered ablative therapies combined with resection or staged approaches. Modern management of hepatic colorectal metastases necessitates a multidisciplinary approach to effectively treat these patients and increase the number of patients who will benefit from resection.

Blood neutrophil-to-lymphocyte ratio predicts survival in patients with colorectal liver metastases treated with systemic chemotherapy

BACKGROUND

Whether neutrophil-to-lymphocyte ratio (NLR) predicts survival of patients with colorectal liver metastases (CLM) treated with systemic chemotherapy remains unclear.

METHODS

Clinicopathologic data were reviewed for patients with CLM treated with chemotherapy and resection (n=200) or chemotherapy only (n=90). Univariate and multivariate analyses for prognostic factors were performed. In the resection group, whether chemotherapy normalizes high NLR and the effect of NLR normalization on survival were evaluated.

RESULTS

In the resection group, patients with preoperative NLR>5 had a worse 5-year survival rate than patients with NLR <or= 5 (19% vs. 43%; P=0.009), and NLR>5 was the only independent preoperative predictor of worse survival (P=0.016; hazard ratio [HR]=2.22; 95% confidence interval [95% CI], 1.16-4.25). In the nonresection group, patients with prechemotherapy NLR>5 had a worse 3-year survival rate than patients with NLR <or= 5 (0% vs. 23%; P=0.0002), and NLR>5 was the only independent predictor of worse survival (P=0.001; HR = 2.91; 95% CI, 1.54-5.50). In the resection group, chemotherapy normalized high NLR in 17 of 25 patients, and these 17 patients had better survival than the 8 patients with high NLR both before chemotherapy and before surgery (P=0.021).

CONCLUSION

NLR independently predicts survival in patients with CLM treated with chemotherapy followed by resection or chemotherapy only. When chemotherapy normalizes high NLR, improved survival is expected.

Predictive value of telomerase reverse transcriptase expression in patients with high risk superficial bladder cancer treated with adjuvant BCG immunotherapy

PURPOSE

We conducted a prospective study to determine whether expression of telomerase reverse transcriptase (hTERT) is associated with recurrence-free-survival (RFS) or development of invasive disease in patients with high risk superficial bladder cancer (SBC) that received adjuvant BCG immunotherapy.

METHODS

Thirty patients with high-grade T1 tumors were evaluated. Pre-BCG TURBT and post-BCG specimens were analyzed for hTERT nucleolar expression by immunohistochemistry.

RESULTS

Post-BCG hTERT expression was statistically significantly lower than pre-BCG hTERT expression. Pre-BCG hTERT nucleolar staining in more than 75% of cells was associated with worse RFS (9 months vs. not yet reached, P = 0.05), while post-BCG hTERT nucleolar staining in more than 50% of the cells was associated with worse RFS (6 months vs. not yet reached, P = 0.001) and development of invasive disease. In multivariate analysis, post-BCG hTERT expression was independently associated with RFS and development of invasive disease.

CONCLUSIONS

Immunohistochemical evaluation of hTERT may help define a subset of high risk SBC patients that will eventually fail BCG and may therefore benefit from early salvage cystectomy.

Pathologic Response to Preoperative Chemotherapy: A New Outcome End Point After Resection of Hepatic Colorectal Metastases

Purpose

The primary goal of this study was to evaluate whether pathologic response to chemotherapy predicts patient survival after preoperative chemotherapy and resection of colorectal liver metastases (CLM). The secondary goal of the study was to identify the clinical predictors of pathologic response.

Patients and Methods

A retrospective review was performed of 305 patients who underwent preoperative irinotecan- or oxaliplatin-based chemotherapy, followed by resection of CLM. Pathologic response was systematically evaluated and reported as the mean of the percentage of cancer cells remaining within each tumor. Univariate and multivariate analyses were performed to identify the predictors of pathologic response and survival.

Results

Cumulative 5-year overall survival rates by pathologic response status were as follows: 75% complete response (no residual cancer cells), 56% major response (1% to 49% residual cancer cells), and 33% minor response (≥ 50% residual cancer cells; complete v major response, P = .037; major v minor response, P = .028). Multivariate analysis revealed that only surgical margin status (P = .050; hazard ratio [HR], 1.77) and pathologic response (major response: P = .034; HR, 4.80; minor response: P = .007; HR, 6.93) were independent predictors of survival. Multivariate analysis of the predictors of pathologic response revealed that carcinoembryonic antigen level ≤ 5 ng/mL, tumor size ≤ 3 cm, and chemotherapy with fluoropyrimidine plus oxaliplatin and bevacizumab were independent predictors of pathologic response.

Conclusion

Pathologic response predicts survival after preoperative chemotherapy and resection of CLM. Degree of pathologic response represents a new outcome end point for prognosis after resection of CLM.

hTERT expression in colorectal adenocarcinoma: correlations with p21, p53 expressions and clinicopathological features

BACKGROUND

The clinicopathological roles and relationships of hTERT, p21 and p53 proteins have not been studied in depth in colorectal cancer. The aim of the present study is to investigate the clinicopathological roles of expression of hTERT protein expression and its relationship with the expression of p21 and p53 proteins in a large cohort of patients with colorectal adenocarcinoma.

MATERIALS AND METHODS

Expressions of hTERT, p21 and p53 proteins were investigated in 188 patients with colorectal adenocarcinomas by immunohistochemistry. The findings were correlated with the clinicopathological features and survival data of colorectal adenocarcinomas.

RESULTS

hTERT, p53 and p21 proteins were detected in 63%, 100% and 62% of the patients with colorectal carcinoma. High level of hTERT protein expression was noted in patients with metastases (p = 0.038) and in patients with rectal cancer (p = 0.046). Loss or low level of p21 protein was often noted in non-mucinous colorectal adenocarcinoma when compared with mucinous adenocarcinoma (p = 0.001). Furthermore, p53 expression was more frequently noted in non-mucinous adenocarcinoma (p = 0.001). The level of expression of p21 protein was positively correlated with expression of level of hTERT protein (p = 0.00001). The survival of the patients was related to staging (p = 0.001) and p53 protein expression (p = 0.038) of the tumours.

CONCLUSIONS

hTERT protein expression is an indicator of the biological aggressiveness of the cancer. The level of expression of the protein was also related to the distal location and level of p21 expression of the tumours.

Clinical significance of telomerase activity in peritoneal disseminated cells: gastrointestinal cancers

Early detection and accurate staging of gastrointestinal (GI) cancers are difficult. The aim of this study was to evaluate whether telomerase activity (TA) in exfoliated/disseminated epithelial cells could be used as a reliable marker for GI cancers. TA was evaluated with the real-time RTQ-TRAP in immunomagnetically sorted peritoneal epithelial cells from 60 patients undergoing surgical treatment. Thirty-two patients were clinically diagnosed with a variety of GI cancers: 1 had premalignant disease, 2 had history of GI cancers, and 25 patients were clinically negative for cancer. Here we report that all types and all cases of gastrointestinal cancers were telomerase positive, thereby demonstrating 100% sensitivity for cancer. Eighteen of 25 nonmalignant cases had undetectable levels of TA, 2 had low, and 5 of 25 expressed high TA levels. Because normal epithelial cells usually have low TA and a lesser tendency to exfoliate compared with cancer cells, it is of great importance to have close follow-up for these patients to exclude possible malignant disease. We conclude that RTQ-TRAP assessment of TA in immunomagnetically sorted peritoneal epithelial cells has 100% sensitivity and 100% negative predictive value for GI cancers, and therefore, can be considered as a valuable tool and useful addition to current standard diagnostic methods. Clinical significance of unusually high telomerase activity in some clinically negative for cancer cases requires further study.

Echogenic appearance of colorectal liver metastases on intraoperative ultrasonography is associated with survival after hepatic resection

Survival after resection of colorectal liver metastases has traditionally been associated with clinicopathologic factors. We sought to investigate whether echogenicity of colorectal liver metastasis as assessed by intraoperative ultrasound (IOUS) was a prognostic factor after hepatic resection. Prospective data on tumor IOUS appearance were collected in 84 patients who underwent hepatic resection for colorectal liver metastasis. Images were digitally recorded, blindly reviewed, and scored for echogenicity (hypo-, iso-, or hyperechoic). The median tumor number was 1 and the median tumor size was 5.0 cm. At the time of surgery, the IOUS appearance of the colorectal liver metastases were hypoechoic in 35 (41.7%) patients, isoechoic in 37 (44.0%) patients, and hyperechoic in 12 (14.3%) patients. Traditional clinicopathologic prognostic factors were similarly distributed among the three echogenicity groups (all p > 0.05). Patients with a hypoechoic lesion had a significantly shorter median survival (30.2 months) compared with patients who had either an isoechoic (53.2 months) or hyperechoic (42.3 months) lesion (p = 0.005). The 5-year survival after hepatic resection of colorectal liver metastasis was also associated with the echogenic appearance of the lesion (hypoechoic 14.4 vs isoechoic 37.4 vs hyperechoic 46.2%) (p < 0.05). Intraoperative ultrasound echogenicity should be considered a prognostic factor after hepatic resection of metastatic colorectal cancer.

Surgical therapy for colorectal metastases to the liver

Colorectal cancer is the fourth most common type of cancer in the West and the second leading cause of cancer-related deaths in the United States. Approximately 35 to 55% of patients with colorectal cancer develop hepatic metastases during the course of their disease. Surgical resection of colorectal liver metastases represents the only chance at potential cure, and long-term survival can be achieved in 35 to 58% of patients after resection. The goal of hepatic resection should be to resect all metastases with negative histologic margins while preserving sufficient functional hepatic parenchyma. In patients with extensive metastatic disease who would otherwise be unresectable, ablative approaches can be used instead of or combined with hepatic resection. The use of portal vein embolization and preoperative chemotherapy may also expand the population of patients who are candidates for surgical treatment. Despite these advances, many patients still experience a recurrence after hepatic resection. More active systemic chemotherapy agents are now available and are being increasingly employed as adjuvant therapy either before or after surgery. Modern treatment of colorectal liver metastasis requires a multidisciplinary approach in an effort to increase the number of patients who may benefit from surgical treatment of colorectal cancer liver metastasis.

Neoadjuvant chemotherapy for patients with liver metastases from colorectal cancer

Colorectal cancer is the second most common type of cancer in industrialized countries. Despite improved resection procedures and optimized adjuvant chemotherapy, local or distant recurrences occur in 22-25% of patients with stage II/III colon cancer. Approximately 30% of patients have advanced disease at presentation. The liver is the most common site of colorectal metastases and, interestingly, 20-30% of patients with colorectal cancer have liver-only metastases. The combined modality of chemotherapy and surgery increases overall survival and the chance of cure for metastatic patients, even if there is no agreement in terms of the best schedule and how long the treatment must last. In this paper, we review the role and the rationale of neoadjuvant chemotherapy within a multimodal approach, and discuss remaining questions and future directions.

Frequent high telomerase reverse transcriptase expression in primary oral squamous cell carcinoma

BACKGROUND

Gene copy number gain of chromosomal arm 5p is frequently found in oral squamous cell carcinoma (OSCC) suggesting the activation of proto-oncogenes. TERT is a candidate gene encoding for human telomerase reverse transcriptase (hTERT). The aim of the present study was to elucidate the relevance of TERT copy number gain and high hTERT expression in OSCC.

METHODS

Fluorescence in situ hybridization (FISH) for TERT and immunohistochemistry (IHC) for hTERT were performed to analyze TERT copy numbers and hTERT expression, respectively, on tissue microarray (TMA) sections including n = 247 OSCC and n = 105 pharyngeal and laryngeal squamous cell carcinomas (PSCC/LSCC).

RESULTS

Increased hTERT protein expression was more frequently found in OSCC (71.1%, 155/218) than in PSCC/LSCC (36.0%, 35/89) (P < 0.001). By contrast, specific TERT amplifications were less common in OSCC (2.1%, 4/191) compared with PSCC/LSCC (9.9%, 8/81) (P = 0.047).

CONCLUSIONS

High hTERT expression is a frequent finding in OSCC. It might be a promising target for the development of specific anti-neoplastic therapy approaches.

Shifting from clinical to biologic indicators of prognosis after resection of hepatic colorectal metastases

Following resection of hepatic colorectal metastases, there are few criteria for predicting which patients have more aggressive disease and are, therefore, more likely to experience recurrence and reduced survival. Traditionally, primary tumor stage, preoperative carcinoembryonic antigen level, time from primary tumor treatment to diagnosis of hepatic metastases (disease-free interval), hepatic tumor size, number of hepatic metastases, and presence of extrahepatic disease have been reported to be predictors of survival after resection. However, the data regarding the prognostic importance of these clinicopathologic factors are inconsistent and conflicting. Therefore, conventional clinicopathologic factors may be inadequate for the purposes of prognostication. More recently, there has been increased interest in identifying biologic indicators that may help better define patients at risk for recurrence after hepatic resection for colorectal metastases. Recent studies have shown that proliferation markers such as p53 expression, tritiated thymidine uptake, thymidylate synthase, Ki-67, and human telomerase reverse transcriptase may be better predictors of outcome after resection of hepatic colorectal metastases. Moreover, tumor response to preoperative chemotherapy may also prove to be a useful predictor of outcome following liver resection for colorectal metastases.

Molecular prognostic markers in resectable colorectal liver metastases: A systematic review

BACKGROUND

Determination of prognosis in patients with resectable colorectal liver metastases (CLM) is desirable in order to improve case selection for surgery and tailor adjuvant treatment according to individual recurrence risk. Conventional clinicopathological factors lack the sensitivity to accurately achieve this goal. Consideration of tumour biology and the identification of molecular prognostic markers may allow more accurate risk stratification.

METHOD

This systematic review examines evidence from published manuscripts looking at molecular markers in resectable colorectal liver metastases and their correlation with disease recurrence and survival following hepatectomy.

RESULTS

Studies have yielded promising results in the search for prognostic molecular markers of CLM. Molecular biomarkers from varied aspects of tumour biology have been examined and a number of these, including proliferation indices, telomerase, thymidylate synthase, microvessel density and thrombospondin-1 appear to have prognostic utility in this context. Validation of other markers, notably p53, has been limited by a failure of methodologies to account for their biological complexity.

CONCLUSIONS

A biomarker-based approach may yield significant benefits through informed treatment of resectable metastatic colorectal malignancy. Standardised retrospective analyses are necessary to confirm preliminary findings and identify existing and novel markers for inclusion into prospective studies. Assessment and verification of multiple molecular markers in this manner may allow molecular profiling of metastases and tailoring of therapy according to the biological aggressiveness of individual tumours. The advent of genomic- and proteomic-based technologies will allow the simultaneous analysis of multiple molecular markers and the derivation of disease profiles associated with disease recurrence and poor survival.

Immunodetection of human telomerase reverse-transcriptase (hTERT) re-appraised: nucleolin and telomerase cross paths

The involvement of telomerase in cellular immortalization and senescence has often been assessed by means of telomerase expression at the RNA level and quantification of telomerase activity by the telomeric repeat amplification protocol assay. However, these methods either neglected the existence of various telomerase splice variants, or ignored the nonconventional functions of telomerase independent of its ability to elongate and maintain telomere length. Immunodetection of telomerase is now being recognized as a necessary approach to precisely elucidate its roles in oncogenesis and senescence. A few antibodies directed against the catalytic subunit of the human telomerase (hTERT) are currently used but their specificity is not always demonstrated. A survey of the literature showed inconsistencies and led us to comparatively re-evaluate the most frequently used antibodies. Surprisingly, mass spectrometry, two-dimensional gel analysis and immunofluorescent experiments revealed that the most frequently used hTERT immunoprobe, a mouse monoclonal antibody that was claimed to be directed against an hTERT protein epitope, in fact recognizes nucleolin rather than telomerase. Our findings have interesting implications regarding the biology of nucleolin and telomerase in the context of pathophysiological investigations recently carried out.

Her-2 targeted therapy: beyond breast cancer and trastuzumab

Her-2 is a validated therapeutic target in breast cancer. The two critical questions that remain regarding Her-2 targeting concern 1) the relevance of Her-2 inhibition in other malignancies and 2) the ability of novel agents to achieve greater Her-2 inhibition than trastuzumab. The contribution of cell signaling effects and immunologic mechanisms to the effect of trastuzumab in vivo remains poorly understood. Thus, the preclinical data that support the greater efficacy of novel Her-2 antibodies or small molecule tyrosine kinase inhibitors remain to be validated in clinical trials. In this review, we discuss the evidence from recent trastuzumab clinical trials as a point of departure for consideration of novel Her-2 targeted therapies. Preliminary results from early clinical trials suggest that Her-2 tyrosine kinase inhibitors may extend the population for which this strategy offers therapeutic effect.

The role of telomeres and telomerase in the pathology of human cancer and aging

Cellular senescence, the state of permanent growth arrest, is the inevitable fate of replicating normal somatic cells. Postulated to underlie this finite replicative span is the physiology of telomeres, which constitute the ends of chromosomes. The repetitive sequences of these DNA-protein complexes progressively shorten with each mitosis. When the critical length is bridged, telomeres trigger DNA repair and cell cycle checkpoint mechanisms that result in chromosomal fusions, cell cycle arrest, senescence and/or apoptosis. Should senescence be bypassed at such time, continued cell divisions in the face of dysfunctional telomeres and activated DNA repair machinery can result in the genomic instability favourable for oncogenesis. The longevity and malignant progression of the thus transformed cell requires coincident telomerase expression or other means to negate the constitutional telomeric loss. Practically then, telomeres and telomerase may represent plausible prognostic and screening cancer markers. Furthermore, if the argument is extended, with assumptions that telomeric attrition is indeed the basis of cellular senescence and that accumulation of the latter equates to aging at the organismal level, then telomeres may well explain the increased incidence of cancer with human aging.

hTERT immunopositivity patterns in the normal brain and in astrocytic tumors

Accumulating data about the impact of hTERT in astrocytic tumor carcinogenesis and recent evidence about its association with disease outcome prompt the evaluation of this molecule with methods applicable in routine pathology practice. In this study, we investigated hTERT protein expression with immunohistochemistry (IHC) and the NCL-hTERT antibody in 49 astrocytic tumors. Results were validated with the assessment of hTERT mRNA (relative quantification, identification of splice variants, in situ hybridization). Specific nuclear hTERT immunostaining patterns (IPs) were characterized as patterns As (single large dot) and Am (multiple dots) without nucleoplasm staining and pattern B (nucleoplasm staining with or without dots), corresponding to low and high relative hTERT expression values (P<0.0001). Low- and high-grade astrocytic tumors were found positive for hTERT in 74 and 85% of cases, respectively. Heterogeneity in the distribution of hTERT-positive cells was observed in all tumors. The prevailing nuclear IPs differed significantly between pilocytic astrocytomas (pattern As) and the rest of histologic types up to glioblastoma (patterns Am and B) (P<0.0001). The described nuclear IPs were also observed in non-neoplastic cells. Positive endothelial cells were found in astrocytic tumors of all grades, even when tumor cells showed no hTERT immunoreactivity. A subset of mature normal neurons was positive for hTERT (pattern As), suggesting a role for this molecule in neuronal maintenance in the adult brain. The nuclear hTERT IPs described here may reflect the functional status of non-neoplastic brain and neoplastic astrocytic cells and support the model of a continuum in the development of glioblastomas from diffuse fibrillary astrocytomas.