Analysis of TP53 aflatoxin signature mutation in hepatocellular carcinomas from Guatemala: A cross-sectional study (2016-2017).

BACKGROUND AND AIMS: Guatemala has the highest incidence of hepatocellular carcinoma (HCC) in the Western hemisphere. The major risk factors in Guatemala are not well characterized, but the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) appears to be low, while the prevalence of aflatoxin (AFB1) exposure appears to be high. To examine whether AFB1 may contribute to the elevated incidence of HCC in Guatemala, this study examined the frequency of the AFB1-signature mutation in the TP53 gene (R249S) as well as other somatic mutations. In addition, we assessed whether the frequency of the TP53 mutation differed by sex. METHODS: Formalin-fixed, paraffin-embedded (FFPE) HCC tissues were obtained from three hospitals in Guatemala City between 2016 and 2017. In addition, tumor tissues preserved in RNAlater were also obtained. Sociodemographic and clinical information including HBV and HCV status were collected. Targeted sequencing of TP53 was performed in the FFPE samples, and a panel of 253 cancer-related genes was sequenced in the RNAlater samples. RESULTS: Ninety-one FFPE tissues were examined, from 52 men and 39 women. Median (IQR) age at diagnosis was 62 (51-70). Among those with known HBV and HCV status, two were HBV+ and three were HCV+. Overall, 47% of the HCCs had a TP53 mutation. The AFB1-signature R249S mutation was present in 24%. No overlap between the R249S mutation and HBV+ was observed in this cohort. Among 18 RNAlater samples examined, 44% had any TP53 mutation and 33% had the R249S mutation. Other somatic mutations were identified in known HCC driver genes. CONCLUSIONS: The presence of the TP53 R249S mutation in the samples studied suggests that AFB1 may contribute to the high incidence of HCC in Guatemala. The proportion of HBV+ tumors was low, suggesting that AFB1 may be associated with HCC in the absence of concomitant HBV infection. Further investigation of AFB1 and other risk factors for HCC in Guatemala is warranted.

NASH and cryptogenic cirrhosis: a histological analysis.

INTRODUCTION: Epidemiological studies indicate that nonalcoholic steatohepatitis (NASH) is a common cause of cirrhosis described as 'cryptogenic'. To address this from a histological perspective and to examine the significance of residual histological findings as an indication of prior NASH, we looked back at biopsies in patients who presented with cirrhosis without sufficient histological features to diagnose NASH but who had prior histologically confirmed non-cirrhotic NASH. METHODS: Seven patients were identified with biopsy pairs showing non-specific (cryptogenic) cirrhosis in the latest specimen and a prior biopsy showing non-cirrhotic NASH. Using an expanded NASH-CRN system scored blindly by light microscopy, we compared the early and late biopsies to each other and to a cohort of 13 patients with cirrhosis due to hepatitis C without co-existing metabolic syndrome. RESULTS: Macrosteatosis, although uniformly present in the non-cirrhotic NASH specimens, declined in the late stage cirrhotic NASH specimens and was not useful in the distinction of late cirrhotic NASH from cirrhotic viral hepatitis. However, the presence of ballooned cells, Mallory-Denk bodies, and megamitochondria and the absence of apoptotic bodies were significantly different in late stage cirrhotic NASH compared to cirrhosis due to hepatitis C. CONCLUSIONS: Histologically advanced NASH presenting as non-specific or cryptogenic cirrhosis has residual changes which are consistent with prior steatohepatitis but which differ from cirrhosis due to hepatitis C. These results provide histological support for the more established epidemiological associations of NASH with cryptogenic cirrhosis and for criteria used in several proposed classifications of cryptogenic cirrhosis.

MKS3-related ciliopathy with features of autosomal recessive polycystic kidney disease, nephronophthisis, and Joubert Syndrome.

OBJECTIVES: To describe 3 children with mutations in a Meckel syndrome gene (MKS3), with features of autosomal recessive polycystic kidney disease (ARPKD), nephronophthisis, and Joubert syndrome (JS). STUDY DESIGN: Biochemical evaluations, magnetic resonance and ultrasound imaging, electroretinograms, IQ testing, and sequence analysis of the PKHD1 and MKS3 genes were performed. Functional consequences of the MKS3 mutations were evaluated by cDNA sequencing and transfection studies with constructs of meckelin, the protein product of MKS3. RESULTS: These 3 children with MKS3 mutations had features typical of ARPKD, that is, enlarged, diffusely microcystic kidneys and early-onset severe hypertension. They also exhibited early-onset chronic anemia, a feature of nephronophthisis, and speech and oculomotor apraxia, suggestive of JS. Magnetic resonance imaging of the brain, originally interpreted as normal, revealed midbrain and cerebellar abnormalities in the spectrum of the "molar tooth sign" that characterizes JS. CONCLUSIONS: These findings expand the phenotypes associated with MKS3 mutations. MKS3-related ciliopathies should be considered in patients with an ARPKD-like phenotype, especially in the presence of speech and oculomotor apraxia. In such patients, careful expert evaluation of the brain images can be beneficial because the brain malformations can be subtle.

Clinical spectrum and histopathologic features of chronic hepatitis C infection in children.

OBJECTIVE: To define the natural history and outcomes of children infected with hepatitis C virus (HCV) at birth or in early childhood. STUDY DESIGN: This retrospective, prospective study identified 60 HCV-infected children through a transfusion look-back program (group 1) and by referrals (group 2). Perinatal/transfusion history, clinical course, and laboratory studies were correlated with findings from 42 liver biopsy specimens. RESULTS: Mean age at infection was 7.1 months, and duration of infection 13.4 years. The sources of infection were blood transfusion (68%), perinatal transmission (13%), and both (7%). Most patients were asymptomatic; three referral patients had advanced liver disease at presentation. Mean alanine aminotransferase level was normal in 25%, 1 to 3 times normal in 62%, and greater than 3 times normal in 13%. Liver biopsy specimens showed minimal to mild inflammation in 71%, absent or minimal fibrosis in 88%, and bridging fibrosis in 12%. Age at infection and serum gamma-glutamyltranspeptidase correlated with fibrosis; serum alanine aminotransferase correlated with inflammation unless complicated by comorbidity. Repeat biopsies within 1 to 4 years in four patients showed no significant progression in three and cirrhosis in one. Two patients died after liver transplantation. CONCLUSIONS: Children with chronic HCV infection are generally asymptomatic. By 13 years after infection, 12% of patients had significant fibrosis. Patients enrolled by referral had more severe liver disease than those identified through the look-back program, demonstrating the importance of selection bias in assessing the long-term outcome of HCV infection.