Background: Telomeres, located at chromosome ends, are progressively shortened during each cell cycle by replication-dependent loss of DNA termini. Although maintenance of telomere length is critical for cell-replicative potential and tumourigenesis, the erosion of telomeres can lead to genetic instability, a pivotal mechanism in the neoplastic process. Patients and methods: A total of 118 colorectal cancer (CRC) samples (53 right-colon, 30 left-colon, and 35 rectal tumours) and corresponding adjacent non-cancerous tissues were evaluated for telomere length, p53 mutation, and microsatellite instability (MSI). Telomere length was estimated by real-time PCR. Results: Telomeres were significantly shorter in CRCs than in adjacent tissues, regardless of tumour stage and grade, site, or genetic alterations (P<0.0001). Moreover, in normal tissues, but not in tumours, telomere length inversely correlated with age (r=−0.24, P=0.017). Telomere length in CRCs did not differ with tumour progression or p53 status; however, in CRCs carrying the wild-type p53, telomeres were significantly shorter in tumours with MSI than in those with stable microsatellites (P=0.027). Furthermore, telomere length differed according to tumour location, being longer in rectal cancers (P=0.03). Conclusions: These findings suggest that telomere shortening is a key initial event in colorectal carcinogenesis. The extent of telomere erosion is related to tumour origin site and may be influenced by the mismatch repair pathway.

Purpose: Colorectal cancer (CRC) is one of the most common cancers in western countries. Identification of circulating markers for CRC would optimize early stage diagnosis and the monitoring for disease recurrence. Expression of telomerase reverse transcriptase (hTERT) is essential to the oncogenic process and might be used as a molecular marker of neoplastic disease. Experimental Design: Eighty-five CRC samples (25 stage I, 15 stage II, 15 stage III, and 30 stage IV), the available corresponding noncancerous mucosa (n = 42), and plasma collected at the time of surgery (n = 49) were analyzed. Control plasma samples were obtained from 43 age-matched healthy subjects. All hTERT transcripts (hTERT-AT) and transcripts encoding the functional protein (hTERT-FL) were quantified by real-time PCR. Results: hTERT-AT was found to correlate with hTERT-FL (r = 0.849; P < 0.0001) mRNA levels in tumors. Both hTERT mRNAs were significantly higher in tumors than in adjacent noncancerous mucosa and both significantly increased with tumor progression (P < 0.0001). In contrast to controls, all but two plasma samples from CRC patients were positive for hTERT mRNAs. Using the cutoff value of 180 copies hTERT-AT/mL, the sensitivity and specificity of the assay for CRC detection were 92% and 100%, respectively. Furthermore, hTERT-AT mRNA levels in plasma significantly correlated with hTERT-AT mRNA levels in tumors (r = 0.702, P < 0.0001). Conclusions: These findings indicate that quantification of hTERT mRNA in plasma may be used as a marker for detection and monitoring of neoplastic colorectal disease.

What are the relationships between telomere lengths in leukocytes and sperm, sperm count and parents' age at conception in a group of apparently healthy subjects of the same age? Sperm telomere length (STL) is related to sperm count, it is lower in oligozoospermic than in normozoospermic men and it is directly related to parents' age at conception. Leukocyte telomere length (LTL) decreases with age but STL increases and offspring of older fathers tend to have longer leukocyte telomeres. Only one study analyzed STL in relation to male fertility, and reported shorter telomeres in infertile versus fertile men. No data have been reported on STL in relation to parents' age at conception. Prospective study conducted from January to December 2012 of 18–19-year-old high school students. The volunteers were 81 apparently healthy subjects, including 61 with normozoospermia and 20 with idiopathic oligozoospermia. Leukocyte and sperm telomere length were measured by real-time PCR. Data were analyzed for determining the relationships between LTL, STL, sperm count and parents' age at conception. Sperm and leukocyte telomere length were strongly correlated, but STL was significantly longer. A significant positive correlation between STL and total sperm number was found. STL was significantly lower in oligozoospermic than in normozoospermic men. Finally, we found a significant positive relationship between maternal age and both leukocyte and sperm telomere length and a significant positive relation between paternal age and STL in the offspring. The relative contributions of mothers' and fathers' ages to their offspring's telomere length could not be determined because of the high correlation between paternal and maternal ages. Although consistent with previous findings, this is the first study on telomere length in oligo- and normozoospermic men and included a relatively low number of subjects. Our study was also restricted to young (18–19 year old) men, so future studies should determine whether our findings can be generalized to men at ages typically encountered at fertility centers. Future studies should also try to determine the possible effect of abstinence time and frequency of ejaculation with STL. Our study sheds new light on the association between STL and sperm count and on the inheritance of telomere length (in leukocytes and sperm) in relation to the parents' age at conception. Additional studies are needed to confirm these observations, to clarify if the association between shorter STL and damaged spermatogenesis represents a pathophysiological link, and to determine the effect on offspring telomere length of assisted reproduction techniques performed on couples of advanced age or where the man is oligozoospermic. This work was supported by the Italian Ministry of University and Research (grant no. 2009AMPA9C to C.F.) and Padova University (grant 2010 to A.D.R.). The authors have no competing interests to declare.

Colorectal cancer (CRC) is the third most common cancer worldwide and, despite improved treatments, is still an important cause of cancer-related deaths. CRC encompasses a complex of diseases arising from a multi-step process of genetic and epigenetic events. Besides heterogeneity in the molecular and biological features of CRC, chromosomal instability is a hallmark of cancer and cancer cells may also circumvent replicative senescence and acquire the ability to sustain unlimited proliferation. Telomere/telomerase interplay is an important mechanism involved in both genomic stability and cellular replicative potential, and its dysfunction plays a key role in the oncogenetic process. The erosion of telomeres, mainly because of cell proliferation, may be accelerated by specific alterations in the genes involved in CRC, such as APC and MSH2. Although there is general agreement that the shortening of telomeres plays a role in the early steps of CRC carcinogenesis by promoting chromosomal instability, the prognostic role of telomere length in CRC is still under debate. The activation of telomerase reverse transcriptase (TERT), the catalytic component of the telomerase complex, allows cancer cells to grow indefinitely by maintaining the length of the telomeres, thus favouring tumour formation/progression. Several studies indicate that TERT increases with disease progression, and most studies suggest that telomerase is a useful prognostic factor. Plasma TERT mRNA may also be a promising marker for the minimally invasive monitoring of disease progression and response to therapy.

Transformation of primary B lymphocytes by Epstein-Barr virus requires the establishment of a strictly latent infection, the expression of several latent viral proteins, and sustained telomerase activity. Our previous findings indicated that induction of hTERT, the rate-limiting catalytic unit of the telomerase complex, was associated with the expression of the viral latent membrane protein 1 (LMP1). In the present study, we demonstrate that ectopic expression of LMP1 in BJAB and Ramos B cells resulted in an increase of hTERT transcripts, thus suggesting that LMP1 acts at the transcriptional level. This was confirmed by transient expression of a luciferase reporter plasmid containing the hTERT promoter cotransfected with an LMP1-expressing vector or transfected into B cells in which LMP1 expression was inducible. Consistently, silencing of LMP1 by small interfering RNA resulted in a reduction ofhTERTtranscripts. We also provide evidence indicating that LMP1-inducedhTERTactivation is independently mediated by NF-κB and by mitogen-activated protein kinase and extracellular signal-regulated kinase 1/2 pathways, whereas CD40, Akt, and mTOR signaling has no involvement. Moreover, our results do not support a role for c-Myc in mediating these effects onhTERT, since ectopic expression of LMP1 did not upregulate c-Myc and silencing of this oncogene or E box mutagenesis failed to inhibit LMP1-inducedhTERTactivation. These findings indicate that LMP1 simultaneously modulates multiple signal transduction pathways in B cells to transactivate thehTERTpromoter and enhance telomerase activity, thus confirming the pleiotropic nature of this viral oncoprotein.

Background B-cell chronic lymphocytic leukemia is a clinically heterogeneous disease; some patients rapidly progress and die within a few years of diagnosis, whereas others have a long life expectancy with minimal or no treatment. Telomere length and telomerase levels have been proposed as prognostic factors; however, very few cases have been characterized for both parameters and no study has analyzed the prognostic value of the telomere/telomerase profile. Design and Methods One hundred and seventy-three cases of chronic lymphocytic leukemia were characterized for telomere lengths and telomerase levels by real-time polymerase chain reaction. Data were correlated with established prognostic markers, IGVH mutational status and chromosomal aberrations, and clinical outcome. Results Telomere lengths were inversely correlated with telomerase levels (r_s= −0.213; P=0.012), and most of the cases of chronic lymphocytic leukemia with high levels (above median) of telomerase had short (below median) telomeres (P=0.0001). Telomerase levels were higher and telomeres were shorter in unmutated IGVH cases than in mutated IGVH ones (P<0.0001). Chronic lymphocytic leukemias with 11q, 17p deletion or 12 trisomy had significantly higher levels of telomerase and shorter telomeres than those with no chromosomal aberration or the sole 13q deletion (P<0.001). Telomere length/telomerase level profiles identified subgroups of patients with different clinical outcomes (P<0.0001), even within the subsets of chronic lymphocytic leukemia defined by IGVH mutational status or chromosomal aberrations. Short telomere/high telomerase profile was independently associated with more rapid disease progression. Conclusions Comprehensive analyses of telomeres, telomerase, chromosomal aberrations, and IGVH mutational status delineate groups of chronic lymphocytic leukemias with distinct biological characteristics and clinical outcomes. The telomere/telomerase profile may be particularly useful in refining the prognosis of chronic lymphocytic leukemia patients with mutated IGVH and no high-risk chromosomal aberrations.