Immunohistochemical pattern of hMSH2/hMLH1 in familial and sporadic colorectal, gastric, endometrial and ovarian carcinomas with instability in microsatellite sequences

Alterations of DNA mismatch repair (MMR) genes are involved in carcinogenesis of sporadic and inherited human cancers characterised by instability of DNA microsatellite sequences (MSI). MSI tumours are usually identified using molecular analysis. In the present investigation, hMLH1 and hMSH2 immunohistochemistry was tested in order to evaluate the utility of this method in predicting MMR deficiency. Colorectal (72), gastric (68), endometrial (44) and ovarian (17) carcinomas were independently evaluated for familial history, histological type of tumour, MSI status and immunohistochemical results. Loss of expression of either hMLH1 or hMSH2 was observed in 51 of 55 (92.8%) MSI tumours, while 145 of 146 microsatellite stable (MSS) tumours expressed both the hMLH1 and hMSH2 gene products. Independently of tumour site, an overall agreement between immunohistochemical and molecular results was observed in 15 hereditary non-polyposis colorectal cancer-related tumours. Among sporadic tumours, only 2 of 60 colorectal and 2 of 66 gastric carcinomas, displaying MSI, expressed both hMLH1 and hMSH2 gene products. All 39 endometrial and 16 ovarian tumours presented a concordant molecular and immunohistochemical profile. These data show that immunohistochemistry is an accurate and rapid method to predict the presence of defective DNA MMR genes and to identify both sporadic and familial MSI tumours.

Homozygosity for the W151X stop mutation in the delta7-sterol reductase gene (DHCR7) causing a lethal form of Smith-Lemli-Opitz syndrome: retrospective molecular diagnosis

Smith-Lemli-Opitz syndrome (SLOS) is a multiple congenital anomalies syndrome caused by an abnormality in cholesterol metabolism. The clinical severity may vary from very mild to lethality in utero, making diagnosis difficult at both ends of the spectrum. Patients with severe SLOS might often escape diagnosis because they die before the correct diagnosis is made. We describe an Austrian family whose first child died neonatally with multiple congenital anomalies. The second pregnancy was terminated because the fetus showed similar severe anomalies ultrasonographically. A further pregnancy ended in a spontaneous first trimester abortion. Clinical diagnosis of SLOS was not considered until the autopsy of the fetus of the terminated pregnancy. Because no material for biochemical testing was available we performed mutational analysis of the DHCR7 gene from paraffin-embedded tissue and a Guthrie card focusing on mutations known to cause a severe SLOS phenotype. This demonstrated homozygosity for the mutation W151X, which has been demonstrated to be a functional null mutation. Our data confirm the concept that homozygosity for functional null alleles of the DHCR7 locus results in intrauterine or perinatal lethality. Furthermore, our findings suggest the usefulness of molecular studies of stored material in similarly affected cases where no material for biochemical analysis is available.

Increased apoptosis of hepatocytes in vascular occlusion after orthotopic liver transplantation

Early vascular occlusion is liable to cause graft failure, and differential diagnosis between this condition and primary nonfunction (PNF) caused by preservation injury may be difficult. Apoptosis has been detected in immunomediated cytotoxicity and is known to be triggered by mild ischemia. In a retrospective analysis we investigated the role of apoptosis in vascular occlusion, PNF, and acute allograft rejection to improve the differential diagnosis of early graft failure. The liver graft histology of 75 patients (46 male, 29 female) a median 47 (1-64) years of age was screened semiquantitatively for the rate of apoptosis on the hematoxylin-eosin stain (HE) and by the in situ end nick labeling technique (TUNEL). This cohort included all patients who developed PNF (n = 9) or vascular occlusion (n = 11) after orthotopic liver transplantation (OLT) in the years 1992 to 1996. Within this period of time we performed 205 OLTs on 189 patients. We further included 22 patients with early acute rejection and 11 controls. The highest rates of apoptotic hepatocytes were seen in vascular occlusion (P < 0.001). Grafts with PNF were explanted 1-3 days after OLT and showed hepatocytes that were 100% necrotic. Cases of acute early rejection showed a significantly higher apoptotic cell count than did normal controls (P < 0.003), increasing in direct proportion to the severity of rejection. Screening biopsies for the rate of apoptosis can improve the efficacy and accuracy of differential diagnosis of early graft failure.

Endocarditis and aortal embolization caused by Aspergillus terreus in a patient with acute lymphoblastic leukemia in remission: diagnosis by peripheral-blood culture

Disseminated infection with Aspergillus terreus is a rare disease that affects only the immunocompromised host. We report a case of systemic infection with A. terreus resulting in endocarditis, aortic embolization, and splenic infarction in a patient with acute lymphoblastic leukemia. Diagnosis through peripheral blood culture, lack of pulmonary involvement, and onset of disease during complete remission from leukemia constitute uncommon features of this case.

Apoptotic hepatocytes in rejection and vascular occlusion in liver allograft specimens

AIMS

Programmed cell death (apoptosis) has been described in different hepatobiliary diseases and in immune-mediated cytotoxicity. Apoptosis of hepatocytes and bile duct epithelial cells was detected in chronic liver allograft rejection. In severe acute rejection a DNA fragmentation in-situ assay showed positivity of apoptotic cells and centrilobular necrosis. Although apoptosis is triggered by ischaemia, the potential role of apoptosis in tissue damage caused by hepatic vascular occlusion after orthotopic liver transplantation has not yet been investigated.

METHODS AND RESULTS

We examined biopsies for apoptotic cell death in 50 liver allografts: 29 with acute liver rejection, six without rejection, five time-zero biopsies, and 10 cases with hepatic artery thrombosis. In addition to a semiquantitative assessment of apoptotic bodies in haematoxylin and eosin stains, an in-situ end nick-labelling technique (TUNEL) was used to detect DNA fragmentation. In all cases with hepatic artery thrombosis the incidence of apoptosis was found significantly increased in comparison to acute rejection.

CONCLUSIONS

As apoptosis is a mechanism in the early stages of tissue damage prior to necrosis, increased apoptosis in liver allograft biopsies might be regarded as a signal of early ischaemia indicating initial vascular occlusion.

Antibodies of the anti-Yo and anti-Ri type in the absence of paraneoplastic neurological syndromes: a long-term survey of ovarian cancer patients

In recent years several authors have described a close correlation between circulating antineuronal antibodies of different types and the occurrence of paraneoplastic neurological syndromes. Because this has not been widely accepted, we screened 300 serum samples from 181 ovarian cancer patients for the presence of circulating antineuronal antibodies by immunofluorescence. The findings were confirmed by immunoblotting. In 11 patients circulating antineuronal antibodies were detected. In 4 patients they were classified as anti-Yo and in 7 as anti-Ri, titres ranging from 1:400 to 1: 204,800. All the patients underwent thorough neurological and neurophysiological investigations, with special regard to paraneoplastic syndrome. None of them had symptoms pointing to a paraneoplastic neurological syndrome, although patients were followed up to 2 years after the first examination. Thus the frequency of circulating antineuronal antibodies in ovarian cancer patients is higher than the frequency of paraneoplastic syndromes, and antibody positivity does not necessarily lead to the appearance of a neurological paraneoplastic syndrome.

[Paraneoplastic neurologic syndromes. Classification and diagnosis]

Paraneoplastic neurologic syndromes may be the presenting symptoms of cancer or appear during the course of the disease. Current knowledge of paraneoplastic syndromes is discussed on the basis of Henson and Urich's classification. The recognition of antineuronal antibodies in some neurologic paraneoplastic syndromes has had an impact on diagnostic possibilities. Additionally, there are new considerations relating to pathogenesis and therapy. Although the value and diagnostic yield of antineuronal antibodies are the subject of major discussion, they are already of significant diagnostic value in the diagnosis of paraneoplastic neurologic syndromes.