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Telomere biology and telomerase mutations in cirrhotic patients with hepatocellular carcinoma.

ABSTRACT: Telomeres are repetitive DNA sequences at linear chromosome termini, protecting chromosomes against end-to-end fusion and damage, providing chromosomal stability. Telomeres shorten with mitotic cellular division, but are maintained in cells with high proliferative capacity by telomerase. Loss-of-function mutations in telomere-maintenance genes are genetic risk factors for cirrhosis development in humans and murine models. Telomerase deficiency provokes accelerated telomere shortening and dysfunction, facilitating genomic instability and oncogenesis. Here we examined whether telomerase mutations and telomere shortening were associated with hepatocellular carcinoma (HCC) secondary to cirrhosis. Telomere length of peripheral blood leukocytes was measured by Southern blot and qPCR in 120 patients with HCC associated with cirrhosis and 261 healthy subjects. HCC patients were screened for telomerase gene variants (in TERT and TERC) by Sanger sequencing. Age-adjusted telomere length was comparable between HCC patients and healthy subjects by both Southern blot and qPCR. Four non-synonymous TERT heterozygous variants were identified in four unrelated patients, resulting in a significantly higher mutation carrier frequency (3.3%) in patients as compared to controls (p = 0.02). Three of the four variants (T726M, A1062T, and V1090M) were previously observed in patients with other telomere diseases (severe aplastic anemia, acute myeloid leukemia, and cirrhosis). A novel TERT variant, A243V, was identified in a 65-year-old male with advanced HCC and cirrhosis secondary to chronic hepatitis C virus (HCV) and alcohol ingestion, but direct assay measurements in vitro did not detect modulation of telomerase enzymatic activity or processivity. In summary, constitutional variants resulting in amino acid changes in the telomerase reverse transcriptase were found in a small proportion of patients with cirrhosis-associated HCC.

SUBMITTER: Donaires FS

PROVIDER: S-EPMC5558955 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND: The laparoscopic approach for liver resections is still limited and controversial. Nevertheless the advantages connected with a mini-invasive approach are significant, especially in cirrhotic patients. In recent years the progress of laparoscopic procedures and the development of new and dedicated technologies have made endoscopic hepatic surgery feasible and safe. The aim of this study was to report the results of our experience in laparoscopic liver surgery for hepatocellular carcinoma (HCC) in cirrhotic patients. METHODS: From 2000 to 2003, 16 patients (10 male, 6 female; age 48-69 years; mean age 60.1 years) with HCC and associated severe but well compensated liver cirrhosis underwent laparoscopic hepatic resections at our department. Mean tumour size was 2.9 cm (range 1-3.9). Seven of these lesions were in the left liver and nine in the right lobe. Laparoscopy was performed under CO(2) pneumoperitoneum. The liver was always examined using laparoscopic ultrasound (US) to confirm the extension of the lesions and their relationships to the vasculature. The Pringle manoeuvre was not used. The transection of liver parenchyma was obtained by the use of a harmonic scalpel. The specimens were placed in a plastic bag and removed without contact to the abdominal wall. RESULTS: There was one conversion to laparotomy for inadequate exposure. In the remaining 15 patients we performed 13 non-anatomical resections, I segmentectomy and I anatomical left lobectomy. The mean operative time was 152 min (range 80-180). Mean blood loss was 280 ml and none of the patients required blood transfusions. In two patients the resection margin was <1 cm but the capsule was not infiltrated at histology. One patient died on the third postoperative day from a severe respiratory distress syndrome. Major morbidities occurred in two patients who developed moderate postoperative ascites, which resolved successfully with conservative treatment. The mean postoperative hospital stay was 8.8 days. Mean follow-up time has been 18 months, and to date no recurrences at the site of resection or port-site metastases have been observed. DISCUSSION: Limited laparoscopic liver resections in cirrhotic patients are technically feasible with a low complication rate when careful selection criteria are followed (hepatic involvement limited and located in the left or anterior right segments, tumour size smaller than 5 cm, Child-Pugh class A). This approach could be considered the best option for the treatment of small esophitic or subcapsular HCC on well compensated cirrhosis and a useful option when it is necessary to perform a left lateral anatomical resection or non-anatomical resection in well selected patients. In fact the mini-invasive approach can minimise the postoperative morbidity rate, which is still too high in this group of patients. It must be performed in highly specialised units by surgeons assisted by all requested technologies and with extensive experience in hepatobiliary and advanced laparoscopic surgery.

Project description:BackgroundTelomerase is an enzyme that catalyzes the addition of nucleotides on the ends of chromosomes. Rare loss of function mutations in the gene that encodes the protein component of telomerase (TERT) have been described in patients with idiopathic pulmonary fibrosis (IPF). Here we examine the telomere lengths and pulmonary fibrosis phenotype seen in multiple kindreds with heterozygous TERT mutations.Methods and findingsWe have identified 134 individuals with heterozygous TERT mutations from 21 unrelated families. Available medical records, surgical lung biopsies and radiographs were evaluated retrospectively. Genomic DNA isolated from circulating leukocytes has been used to measure telomere lengths with a quantitative PCR assay. We find that telomere lengths of TERT mutation carriers decrease in an age-dependent manner and show progressive shortening with successive generations of mutation inheritance. Family members without TERT mutations have a shorter mean telomere length than normal, demonstrating epigenetic inheritance of shortened telomere lengths in the absence of an inherited TERT mutation. Pulmonary fibrosis is an age-dependent phenotype not seen in mutation carriers less than 40 years of age but found in 60% of men 60 years or older; its development is associated with environmental exposures including cigarette smoking. A radiographic CT pattern of usual interstitial pneumonia (UIP), which is consistent with a diagnosis of IPF, is seen in 74% of cases and a pathologic pattern of UIP is seen in 86% of surgical lung biopsies. Pulmonary fibrosis associated with TERT mutations is progressive and lethal with a mean survival of 3 years after diagnosis. Overall, TERT mutation carriers demonstrate reduced life expectancy, with a mean age of death of 58 and 67 years for males and females, respectively.ConclusionsA subset of pulmonary fibrosis, like dyskeratosis congenita, bone marrow failure, and liver disease, represents a "telomeropathy" caused by germline mutations in telomerase and characterized by short telomere lengths. Family members within kindreds who do not inherit the TERT mutation have shorter telomere lengths than controls, demonstrating epigenetic inheritance of a shortened parental telomere length set-point.

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Telomere biology and telomerase mutations in cirrhotic patients with hepatocellular carcinoma.

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