CAC did not significantly different from SC in term of cecal intubation time and polyp detection rate.

The aim of this study was to examine the importance of the serum hepatitis C viral load within the first year post-liver transplant in determining posttransplant survival. A retrospective analysis of 118 consecutive hepatitis C virus-positive liver transplant recipients who received an allograft from January 1997 to September 2005 was undertaken with a median duration of follow-up of 32.4 months. Univariate and multivariate analyses were used to examine the effects of recipient, donor, surgical, and viral factors on posttransplant outcomes. A total of 620 viral load estimations were undertaken in the first 12 months following transplantation. Patient and graft survival rates at 1, 3, and 5 years were 87.8%, 79.9%, and 70.1% and 87.0%, 79.2%, and 68.2%, respectively. According to multivariate analysis, a peak viral load Ն 10 7 IU/mL (P ϭ 0.004; hazard ratio, 8.68; 95% confidence interval, 2.04-37.02) and exposure to antirejection therapy (P ϭ 0.05; hazard ratio, 2.26; 95% confidence interval, 1.01-5.38) were both independent predictors of diminished patient and graft survival and hepatitis C-related allograft failure. The only other independent predictor of hepatitis C virus-related outcome after transplant was azathioprine use, which was associated with improved outcomes (P ϭ 0.04; hazard ratio, 0.25; 95% confidence interval, 0.07-0.91). A peak viral load in the first year after transplant of Ͼ10 8 , 10 7 to 10 8 , and Ͻ10 7 IU/mL was associated with a mean survival of 11.8, 70.6, and 89.1 months respectively (P Յ 0. Cirrhosis related to chronic infection with hepatitis C virus (HCV) has emerged as the most frequent indication for orthotopic liver transplantation. Presently, approximately 50% of transplants performed in the United States and Europe are for patients infected with HCV.1 The health burden due to HCV is expected to increase to such a degree that by the year 2020, the proportion of untreated HCV patients developing cirrhosis will have increased by 30%.1 Furthermore, it is projected that the number of HCV patients with cirrhosis will double and the number of HCV patients with cirrhosis developing hepatocellular carcinoma (HCC) will increase by 80%.

Spontaneous histopathological regression of cancer has been reported. The involvement of the immune system in such regression has been advocated, leading to the theory of immunological surveillance against cancer. A prediction of this theory is that common tumour antigens can be recognized upon repeated exposure by cell-mediated immunity, which leads to tumour regression and the subsequent appearance of tumour antigen-loss variants. However, no direct evidence has been provided in non-viral-induced experimental animal models of primary malignancy or in human primary cancer. This study examined two groups of melanoma patients where histopathological regression of the primary tumour was observed. Many of the 23 patients with multiple (> or =3) primary melanomas showed significant regression of their last melanoma (median 33%, mean 40) compared with matched melanomas from patients with a single primary melanoma (median 0%, mean 12) (p=0.0080), or compared with their first primary melanoma (p=0.0013). Regression was consistent with an 'immunization effect' seen in murine tumour transplantation studies, where inoculation with > or =3 asynchronous tumours induces transplantation rejection on subsequent challenge. A significant decrease in the expression of the melanoma common tumour antigen MART-1 in the last primary tumour from multiple melanoma patients (median 8%, mean 24) versus matched single melanoma patients (median 79%, mean 68) (p=0.0041) and in the last versus first tumour in multiple primary patients was found (p=0.0083). Metastases from 17 patients whose primary skin melanomas had completely regressed (occult primary melanoma) also showed significant MART-1 loss (median 0%, mean 11) compared with matched metastases from patients with non-regressing primary melanoma (median 51%, mean 50) (p=0.0013). MART-1 antigen-loss variants observed in the multiple primary and occult primary patients correlated with the presence of peripheral blood MART-1-specific cytotoxic T lymphocytes (CTLs) (p=0.03). No similar effects were observed with two other melanoma antigens, gp100 and CD63. Thus, in two groups of human melanoma patients, evidence is provided for histopathological tumour regression associated with cancer immune surveillance.

The cullin‐4‐based RING‐type (CRL4) family of E3 ubiquitin ligases functions together with dedicated substrate receptors. Out of the ˜29 CRL4 substrate receptors reported, the DDB1‐ and CUL4‐associated factor 1 (DCAF1) is essential for cellular survival and growth, and its deregulation has been implicated in tumorigenesis. We carried out biochemical and structural studies to examine the structure and mechanism of the CRL4DCAF1 ligase. In the 8.4 Å cryo‐EM map of CRL4DCAF1, four CUL4‐RBX1‐DDB1‐DCAF1 protomers are organized into two dimeric sub‐assemblies. In this arrangement, the WD40 domain of DCAF1 mediates binding with the cullin C‐terminal domain (CTD) and the RBX1 subunit of a neighboring CRL4DCAF1 protomer. This renders RBX1, the catalytic subunit of the ligase, inaccessible to the E2 ubiquitin‐conjugating enzymes. Upon CRL4DCAF1 activation by neddylation, the interaction between the cullin CTD and the neighboring DCAF1 protomer is broken, and the complex assumes an active dimeric conformation. Accordingly, a tetramerization‐deficient CRL4DCAF1 mutant has higher ubiquitin ligase activity compared to the wild‐type. This study identifies a novel mechanism by which unneddylated and substrate‐free CUL4 ligases can be maintained in an inactive state.