The ubiquitin-proteasome system is a major regulatory pathway of protein degradation and plays an important role in cellular division. Fbxw7 (or hCdc4), a member of the F-box family of proteins, which are substrate recognition components of the multisubunit ubiquitin ligase SCF (Skp1-Cdc53/ Cullin-F-box-protein), has been shown to mediate the ubiquitin-dependent proteolysis of several oncoproteins including cyclin E1, c-Myc, c-Jun, and Notch. The oncogenic potential of Fbxw7 substrates, frequent allelic loss in human cancers, and demonstration that mutation of FBXW7 cooperates with p53 in mouse tumorigenesis have suggested that Fbxw7 could function as a tumor suppressor in human cancer. Here, we carry out an extensive genetic screen of primary tumors to evaluate the role of FBXW7 as a tumor suppressor in human tumorigenesis. Our results indicate that FBXW7 is inactivated by mutation in diverse human cancer types with an overall mutation frequency of f6%. The highest mutation frequencies were found in tumors of the bile duct (cholangiocarcinomas, 35%), blood (T-cell acute lymphocytic leukemia, 31%), endometrium (9%), colon (9%), and stomach (6%). Approximately 43% of all mutations occur at two mutational ''hotspots,'' which alter Arg residues (Arg 465 and Arg 479 ) that are critical for substrate recognition. Furthermore, we show that Fbxw7Arg465 hotspot mutant can abrogate wild-type Fbxw7 function through a dominant negative mechanism. Our study is the first comprehensive screen of FBXW7 mutations in various human malignancies and shows that FBXW7 is a general tumor suppressor in human cancer.

The incidence and prevalence figures confirm that AIH is a fairly uncommon disease in the Swedish population. Symptoms at presentation were unspecific, but almost half of the patients were jaundiced, with around 30% having liver cirrhosis. The majority of Swedish AIH patients had AIH type 1.

Abstract. Wei G, Bergquist A, Broomé U, Lindgren S, Wallerstedt S, Almer S, Sangfelt P, Danielsson Å , Sandberg-Gertzén H, Lööf L, Prytz H, Björnsson E (Sahlgrenska University Hospital, Gothenburg; Karolinska University Hospital, Huddinge, Stockholm; University Hospital MAS, Malmö; University Hospital, Linköping; University Hospital, Uppsala; University Hospital, Umeå; University Hospital, Ö rebro; Central Hospital, Västerås; and University Hospital, Lund; Sweden). Acute liver failure in Sweden: etiology and outcome. Results. A total of 279 patients were identified. The most common cause of ALF were acetaminophen toxicity in 42% and other drugs in 15%. In 31 cases (11%) no definite etiology could be established. The KCH criteria had a positive-predictive value (PPV) of 67%, negative-predictive value (NPV) of 84% in the acetaminophen group. Positive-predictive value and negative-predictive value of KCH criteria in the nonacetaminophen group were 54% and 63% respectively. MELD score >30 had a positive-predictive value of 21%, negative-predictive value of 94% in the acetaminophen group. The corresponding figures for the nonacetaminophen group were 64% and 76% respectively.Conclusions. Acetaminophen toxicity was the most common cause in unselected patients with ALF in Sweden. KCH criteria had a high NPV in the acetaminophen group, and in combination with MELD score <30 predicts a good prognosis in acetaminophen patients without transplantation.

SUMMARY BackgroundReliable epidemiological data for portal vein thrombosis are lacking.

Budd-Chiari syndrome is a rare disorder; the mean age-standardised incidence and prevalence rates in Sweden in 1990-2001 were calculated to be 0.8 per million per year and 1.4 per million inhabitants respectively. The presence of a myeloproliferative disorder was a common aetiological factor in our cohort and about half of the patients had a multifactorial aetiology. The transplantation-free survival was poor.