Microsatellite instability mutator phenotype in hepatocellular carcinoma in non-alcoholic and non-virally infected normal livers

Microsatellite instability (MSI) seems to be a rare event in hepatocarcinogenesis and might actually be associated with the progression of hepatocellular carcinoma (HCC) in which the liver is often the site of chronic hepatitis or cirrhosis. The aim of this work was to define the MSI phenotype in HCC affecting exclusively normal livers to avoid slippage errors due to cirrhosis. One hundred and sixty-four patients with HCC affecting non-cirrhotic livers were operated on in our hospital between 1984 and 2001. We analyzed 37 patients selected for low alcohol consumption and the absence of HBV or HCV infection. All the livers were histologically normal. MSI was analyzed according to the criteria defined during the conference consensus workshop for colorectal cancer. High MSI (MSI-H > 30%) was found in 6 (16%) and low MSI (MSI-L < 30%) in 10 (27%) of the 37 HCCs. None of the 10 microsatellite markers tested were altered in the remaining 21 tumors (57%). Immunohistochemistry showed that normal amounts of hMLH1 and hMSH2 were present both in MSI-H and in MSI-L HCCs. MSI-H was significantly associated with more aggressive histological tumor features and a shorter median delay before recurrence. Thus, we have found a small subgroup of HCC tumors which can be considered as a new clinical/histological entity.     

IgG-sandwich and IgM-capture enzyme-linked immunosorbent assay for the detection of antibody to Rift Valley fever virus in domestic ruminants

The recent occurrence of the first confirmed outbreaks of Rift Valley fever in humans and livestock outside the African region, namely in the Kingdom of Saudi Arabia and Yemen, is of global medical and veterinary concern. Disadvantages of classical techniques for serological diagnosis of Rift Valley fever include health risk to laboratory personnel, restrictions for their use outside endemic areas and inability to distinguish between different classes of immunoglobulins. We report on the development and validation of sandwich and capture ELISAs (both based on inactivated antigen) for detection of IgG and IgM antibody to Rift Valley fever virus in bovine, caprine and ovine sera. Compared to virus neutralisation and haemagglutination-inhibition tests, the IgG sandwich ELISA was more sensitive in detection of the earliest immunological responses to infection or vaccination with Rift Valley fever virus. Its sensitivity and specificity derived from field data sets ranged in different ruminant species from 99.05 to 100% and from 99.1 to 99.9%, respectively. The specificity of IgM-capture ELISA varied between different species from 97.4 to 99.4%; its sensitivity was 100% in sheep tested 5-42 days post-infection. Our results in field-collected, experimental and post-vaccination sera demonstrate that these assays will be useful for epidemiological surveillance and control programmes, import/export veterinary certification, early diagnosis of infection, and for monitoring of immune response in vaccinated animals. As highly accurate and safe tests, they have the potential to replace traditional diagnostic methods, which pose biohazard risks limiting their use outside of endemic areas to high containment facilities.