Short telomeres and chromosome instability prior to histologic malignant progression and cytogenetic aneuploidy in papillary urothelial neoplasms

Telomere lengths in Barrett's esophagus as a precancerous lesion

BACKGROUND

We have reported that precancerous conditions and lesions invariably have shorter telomeres and associated chromosomal instability relative to normal tissue.

METHODS

Using the Q-FISH method and our original software, Tissue Telo, we estimated telomere lengths in cardiac- and intestinal-type mucosae in 48 cases of Barrett's esophagus (short-segment (SS) n = 18; long-segment (LS) n = 30).

RESULTS

There were no significant differences in telomere length between the cardiac and intestinal types in any of the 48 cases, suggesting that the presence or absence of goblet cells in the columnar segments is unrelated to telomere-dependent chromosomal instability in Barrett's esophagus. In LS Barrett's esophagus, telomeres were shorter in cardiac-type than in intestinal-type mucosa, suggesting that the former may play a more important role than the latter as a precancerous lesion in LS. Telomeres in cardiac-type mucosa were longer in SS than in LS, supporting the possibility that cardiac-type LS may pose a higher risk as a precancerous lesion than cardiac-type SS.

CONCLUSIONS

Although it has been considered that Barrett's carcinoma arises only from intestinal-type mucosa, our present findings support previous histogenetic studies suggesting that cardiac-type mucosa is more important as a precancerous condition in Barrett's esophagus than anticipated.

Telomere length of gallbladder epithelium is shortened in patients with congenital biliary dilatation: measurement by quantitative fluorescence in situ hybridization

BACKGROUND

Congenital biliary dilatation (CBD) is a congenital malformation involving both dilatation of the extrahepatic bile duct and pancreaticobiliary maljunction. Persistent reflux of pancreatic juice injures the biliary tract mucosa, resulting in chronic inflammation and higher rates of carcinogenesis in the biliary tract, including the gallbladder. Telomeres are repetitive DNA sequences located at the ends of chromosomes. Chromosomal instability due to telomere dysfunction plays an important role in the carcinogenesis of many organs. This study was performed to determine whether excessive shortening of telomeres occurs in the gallbladder mucosa of patients with CBD.

METHODS

Resected gallbladders were obtained from 17 patients with CBD, ten patients with cholecystolithiasis without pancreatic juice reflux, and 17 patients with normal gallbladders (controls) (median age of each group of patients: 37, 50, and 53 years, respectively). The telomere lengths of the gallbladder epithelium were measured by quantitative fluorescence in situ hybridization using tissue sections, and the normalized telomere-to-centromere ratio (NTCR) was calculated.

RESULTS

The NTCRs in the CBD, cholecystolithiasis, and control groups were 1.24 [interquartile range (IQR) 1.125-1.52], 1.96 (IQR 1.56-2.295), and 1.77 (IQR 1.48-2.53), respectively. The NTCR in the CBD group was significantly smaller than that in the cholecystolithiasis and control groups (p = 0.003 and 0.004, respectively), even in young patients.

CONCLUSIONS

Our findings indicate that telomere shortening in the gallbladder mucosa plays an important role in the process of carcinogenesis in patients with CBD. These results support the recommendation of established guidelines for prophylactic surgery in patients with CBD because CBD is a premalignant condition with excessive telomere shortening.

Diagnostic difficulties in cases of papillary urothelial neoplasm of low malignant potential, urothelial proliferation of uncertain malignant potential, urothelial dysplasia and urothelial papilloma: A review of current literature

Tumours of the urinary tract are the fifth most frequent type of cancer. The most common types are urothelial tumours, among which, non-invasive urothelial neoplasms represent 45% of all cases. The 2016 WHO classification of urinary tract tumours introduced new classifications of non-invasive lesions. Besides urothelial papilloma (UP) and papillary urothelial neoplasm of low malignant potential (PUNLMP), as described in the former classification, the new classification also includes new entities such as urothelial proliferation of uncertain malignant potential (UPUMP) and urothelial dysplasia (UD). Of the aforementioned, UPUMP is the lesion that most commonly progresses, but solely to non-invasive carcinomas. UD is associated with a high risk of progression to invasive carcinoma. Understanding the biological character, and establishing the correct differential diagnosis in cases of non-invasive, non-cancerous lesions of the urinary bladder, will be of importance in establishing outcome predictions for future patients. A systematic review of the current literature allows us to systematize genetic, morphologic and prognostic factors of such lesions. Moreover, the collected data provide the basis for a proposed diagnostic algorithm which facilitates quick and effective differential diagnoses in cases of non-invasive non-cancerous urinary bladder lesions.

TERT rs2736098 (Ex2-659G>A) polymorphism and cancer susceptibility: evidence from a comprehensive meta-analysis

Increasing researches have been performed regarding the relationship between TERT rs2736098 and cancer risk, but no consensus has been reached about the relationship. Here, we conducted this updated meta-analysis, aiming to comprehensively evaluate the role of TERT rs2736098 in cancer risk. We systematically searched potential relevant articles through PubMed, EMBASE, CNKI, and WanFang database before August 2017. A total of 33 studies with 18685 cases and 23820 controls were finally included in the current meta-analysis. We then adopted odds ratios (ORs) and 95% confidence intervals (CIs) to analyze the contributions of TERT rs2736098 to cancer risk. We found that the TERT rs2736098 polymorphism was associated with risk of cancer in overall analysis (AA vs. GG: OR = 1.26, 95% CI = 1.09–1.47; AA vs. AG/GG: OR = 1.22, 95% CI = 1.09–1.36; AA/AG vs. GG: OR = 1.13, 95% CI = 1.02–1.24; A vs. G: OR = 1.11, 95% CI = 1.04–1.20). Furthermore, in analysis stratified by cancer type, ethnicity, control source, quality score, and Hardy-Weinberg equilibrium (HWE) in controls, we found increased risk of cancer among lung cancer, bladder cancer, breast cancer, colorectal cancer, other cancers, Asians, hospital-based subgroup, score > 9 group, as well as controls agreement with HWE group. Despite some limitations, the current meta-analysis represented the largest and the most comprehensive investigations, with the strongest conclusion than ever before. To further explicit the association between TERT rs2736098 and cancer risk, more well-design case-control studies with larger sample size are warranted in the future.

Changes of telomere status with aging: An update

Accumulated data have shown that most human somatic cells or tissues show irreversible telomere shortening with age, and that there are strong associations between telomere attrition and aging-related diseases, including cancers, diabetes and cognitive disorders. Although it has been largely accepted that telomere attrition is one of the major causes of aging-related disorders, critical aspects of telomere biology remain unresolved, especially the lack of standardized methodology for quantification of telomere length. Another frustrating issue is that no potentially promising methods for safe prevention of telomere erosion, or for telomere elongation, have been devised. Here, we review several methods for quantification of telomere length currently utilized worldwide, considering their advantages and drawbacks. We also summarize the results of our recent studies of human cells and tissues, mainly using quantitative fluorescence in situ hybridization and Southern blotting, including those derived from patients with progeria-prone Werner syndrome and trisomy 21, and several strains of induced pluripotent stem cells. We discuss the possible merits of using telomere shortness as an indicator, or a new marker, for diagnosis of precancerous states and aging-related disorders. In addition, we describe newly found factors that are thought to impact telomere dynamics, providing a new avenue for examining the unsolved issues related to telomere restoration and maintenance.