Proviral insertions near cyclin D1 in mouse lymphomas: a parallel for BCL1 translocations in human B-cell neoplasms.

By isolating genomic DNA clones that encompass the mouse Cyl-1 (cyclin D1) locus, we have identified a putative CpG island close to the 5' end of the gene. Pulsed-field gel electrophoresis with probes derived from either the 5' or 3' side of the CpG island established physical linkage to two independent markers on mouse chromosome 7, in a region that is syntenic with human chromosome 11q13. On the 3' side, Cyl-1 is approximately 75 kb from Hst-1 and Int-2, although there is an additional CpG island in the intervening DNA, while on the 5' side, Cyl-1 is less than 300 kb from Fis-1, an integration site for Friend murine leukaemia virus. As there is no intervening CpG island, proviral insertions at Fis-1 could influence the expression of Cyl-1 and we describe two virally induced tumours in which this appears to be the case. The data suggest that proviral insertions near Cyl-1 in mouse lymphomas are functionally equivalent to the BCL1 translocations that activate cyclin D1 expression in human B-cell malignancies.

D11S287, a putative oncogene on chromosome 11q13, is amplified and expressed in squamous cell and mammary carcinomas and linked to BCL-1.

Approximately 15 to 20% of primary breast cancers and an even higher proportion of squamous cell carcinomas of the head and neck show amplification of DNA markers on band q13 of human chromosome 11. However, known genes within the amplified region, such as the FGF-related oncogenes INT-2 and HST-1, are very rarely expressed in these tumors. Here we show that another candidate oncogene, designated D11S287, implicated in the pathogenesis of parathyroid adenomas, is also amplified in breast cancers. Significantly, it is consistently coamplified with INT-2 and HST-1 in 36 out of 202 primary tumors, including one case in which the amplified unit did not encompass the translocation breakpoint marker BCL-1. This implies that D11S287 is on the same side of the breakpoint as INT-2, and pulsed-field gel electrophoresis indicates that D11S287 is less than 250 kb from the BCL-1 marker. Since D11S287 RNA was present at elevated levels in a group of tumors and cell lines in which the 11q13 region is amplified, it may be the key oncogene on this amplified unit, and could also be activated by BCL-1 translocations.

Basal ganglia calcification in BB/E rats with diabetes.

Human diabetes is associated with cognitive impairment and structural abnormalities in the brain such as cerebral atrophy. The aetiology of these abnormalities is not known. The BB/E rat is a well-established model of type 1 (insulin dependent) diabetes. A cohort of 34 BB/E rats with diabetes was divided into three sub-groups according to age (and duration of diabetes). Basal ganglia calcification (BGC) was present in the brains of more than 50% of diabetic animals, but not in any of 37 non-diabetic BB/E rats. BGC occurred more commonly in those animals which had the longest duration of diabetes (p=0.001), such that BGC was present in only 8% of animals with diabetes for 20 weeks, but in 100% of animals with diabetes for 60 weeks. There were no other significant light microscopic neuropathologic changes in diabetic animals. It will be important to investigate the mechanism of brain calcification, whether a similar process occurs in humans with diabetes, and its possible relationship to cognitive decline.

Cerebral infarction in adult AIDS patients: observations from the Edinburgh HIV Autopsy Cohort.

BACKGROUND AND PURPOSE: Autopsy series of patients with AIDS have found a 4% to 29% prevalence of cerebral infarction. Little is known of the prevalence of cerebral infarction when not associated with non-HIV central nervous system (CNS) infection, lymphoma, or cardioembolic sources. Clinical correlation has seldom been available. We describe the pathological and clinical features of patients from the Edinburgh HIV Cohort Study found to have had cerebral infarcts without evidence of non-HIV CNS infection, CNS lymphoma, or cardioembolic sources at autopsy. METHODS: From 183 autopsy cases, 26 without evidence of opportunistic cerebral infection or lymphoma were selected. These 26 cases went through a second selection process in which the presence of cerebral infarction, in the absence of the conditions mentioned, was verified. Histology and clinical records for the remaining patients were reviewed. RESULTS: Ten (5.5%) cases fulfilled the inclusion criteria and demonstrated similar hypoxic-ischemic lesions. Small-vessel thickening was seen in all cases, and perivascular space dilatation, rarefaction, and pigment deposition, with vessel wall mineralization and perivascular inflammatory cell infiltrates, were seen in some cases. Vasculitis was not found. One patient had had a transient ischemic attack, and no patient had had a stroke. CONCLUSIONS: Cerebral infarcts in HIV-infected patients are not common in the absence of cerebral non-HIV infection, lymphoma, or embolic sources. We found an HIV-associated vasculopathy with similar features in all risk groups. In AIDS patients presenting with stroke or transient ischemic attack, potentially treatable causes, such as cerebral coinfection or tumor, should be sought.

Gene amplification on chromosome band 11q13 and oestrogen receptor status in breast cancer.

We have analysed DNA from 183 primary breast cancers for amplification or rearrangement of a number of cellular proto-oncogenes, focusing primarily on a cluster of markers on the long arm of chromosome 11. Two of these oncogenes, INT2 and HST1, both of which encode members of the fibroblast growth factor family, are implicated in the generation of virally induced mammary tumours in mice. Here we confirm earlier reports that the q13 region of chromosome 11, in which these genes are tandemly linked, is modestly amplified in approximately 15% of primary human breast cancers. This amplification is confined, with one exception, to cases in which the oestrogen receptor (ER) levels are in excess of 20 fmol/mg protein (P = 0.001). However, DNA amplification does not usually result in detectable expression of either the INT2 or HST1 gene. The data imply that some other gene in the vicinity must contribute to the development of a subset of ER-positive tumours and that assessing the amplification of this region of DNA may be of value in defining a separate category of ER-positive tumour.

Ductal adenoma of the breast--a review of fifteen cases.

The term ductal adenoma has been recently introduced to describe a solid benign lesion of breast ducts. This study describes the clinical, morphologic, and immunohistochemical features of 15 cases of ductal adenoma. Ductal adenomas are usually single, occasionally multiple, lesions occupying medium- and large-sized breast ducts. They may occur in women of all ages, although the majority of patients are 60 years of age or greater. Ductal adenomas usually present clinically as breast lumps which may mimic carcinoma; less commonly, they are associated with nipple discharge. Patients in this series showed no family or previous history of breast disease and had uneventful follow-up after local excision. Despite often showing worrying pseudoinfiltration and cytologic atypia, the immunohistochemical demonstration of a myoepithelial layer and intact basement membrane around the tubules was clear evidence of the benign nature of the lesions. We conclude that most ductal adenomas evolve by sclerosis of benign intraduct papillary lesions, although processes similar to sclerosing adenosis and, possibly, duct ectasia may contribute to the pathogenesis of a proportion of cases. It is hoped that a wider appreciation of the entity of ductal adenoma will reduce the diagnostic uncertainty that continues to surround these and related lesions.

Breast lymphomas: a clinicopathologic review.

Primary lymphoma is an uncommon tumor in the breast. Review of the literature shows two distinct clinicopathologic groups. One, which affects young women, is frequently bilateral, is often associated with pregnancy, and is a Burkitt-type lymphoma. The second group affects older women, is usually B-cell non-Hodgkins-type lymphoma, and presents clinical features identical to carcinoma of the breast. Three recent studies have suggested that up to half of the cases in the latter group belong to the category of lymphomas arising from the mucosa-associated lymphoid tissues. We have identified nine cases of primary lymphoma from the files of Guys Hospital Clinical Oncology Breast Unit in the 16-year period from 1974 to 1990. The clinical features have been reviewed and the tumors have been evaluated both on a morphologic and an immunohistochemical basis, and seven of nine of the cases have been screened for t[14;18] translocation using the polymerase chain reaction. All the tumors occurred in women older than 50 years and who presented with features of mammary carcinoma. One tumor was true histiocytic lymphoma; the remaining eight cases were B-cell lymphomas. Seven of the latter cases were high-grade B-cell lymphomas and one was a true follicular lymphoma. None of our cases showed the features of lymphoma arising in mucosa-associated lymphoid tissue.

Neuropathologic characterization of a rodent model of closed head injury--addition of clinically relevant secondary insults does not significantly potentiate brain damage.

We have characterized the early brain pathology in Sprague-Dawley rats subjected to a modified Richmond impact acceleration model of closed head injury (CHI). This model was modified to produce maximal traumatic brain injury (TBI) in the absence of skull fracture, extracerebral or intracerebral hemorrhage, or brain contusion. We then used this model to assess the neuropathologic effects of superimposed secondary insults, which were designed to reflect a clinically relevant combination of hypotension and pyrexia. Acute neuronal injury, blood-brain barrier (BBB) integrity, axonal injury (AI), and glial activation were studied 4 1/2 hours following either CHI (group A), CHI plus secondary insults (group B), secondary insults alone (group C), or sham control injury (group D). There was evidence of limited AI following CHI in the lower medulla and upper cervical cord region, which was not modified by addition of secondary insult. Loss of dendritic microtubule-associated protein MAP2 immunoreactivity proved a reliable marker of acute neuronal damage, which was confined to subimpact and inferolateral cortical locations following CHI and was widespread after secondary insult. The pattern of plasma protein extravasation paralleled that of acute neuronal injury. We found no evidence of microglial activation, either local or generalized, by 4 1/2 hours. However, by this time CHI and secondary insults had combined to produce evidence of subimpact astrocyte activation, which was not apparent with either insult or injury alone. We conclude that in this modified Richmond model of CHI, when combined with secondary insults, there is no convincing potentiation of brain damage with the minor exception of astrocyte activation.

Atherosclerotic plaque at the carotid bifurcation: CT angiographic appearance with histopathologic correlation.

BACKGROUND AND PURPOSE: The likelihood that carotid plaque will give rise to cerebral ischemia probably relates to the degree of arterial stenosis and to plaque morphology. The aim of this study was to assess whether features seen at CT angiography might be used to predict carotid plaque stability by comparing CT angiograms with histopathologic examinations of the carotid artery bifurcation. METHODS: Nine patients with symptomatic severe carotid stenosis at intraarterial angiography had CT angiography of the carotid bifurcation before carotid endarterectomy. After endarterectomy, multiple sections of the specimens through the carotid bifurcation were examined histologically. Plaque characteristics recorded included the proportion of necrotic/lipid core, presence of hemorrhage, extent of fibrosis, ulceration, calcification, inflammatory cell infiltrate, and fibrous cap thickness. Corresponding CT angiograms were assessed for plaque size, distribution, and radiodensity as well as presence of calcific density and ulceration. Histologic findings and CT angiograms were compared. RESULTS: Plaque with a large necrotic/lipid core, which was often hemorrhagic, was found in 16 of 23 sections, and in 15 of these this histologic appearance corresponded with patchy or homogeneous low density on CT angiograms. Six of seven predominantly fibrous plaques were of soft-tissue density on CT angiograms. High density consistent with calcification was seen more frequently on CT angiograms than it was detected histologically, but CT angiography depicted plaque ulceration poorly (four ulcers at histology; two false-positive and two false-negative findings at CT angiography). CONCLUSION: CT angiography is a promising method for assessing the lumen and wall of the carotid artery. The apparent correlation between histologic appearance and plaque density on CT angiograms has important implications for the prediction of plaque stability, even though ulceration is shown inconsistently.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)--confirmation by cerebral biopsy in 2 cases.

CADASIL is a recently recognized familial form of subcortical multi-infarct dementia. The pathogenesis of the disease is unknown, but it is characterized pathologically by a novel vasculopathy affecting leptomeningeal and subcortical arteries. We describe 2 cases in which the diagnosis could be made from the cerebral biopsy appearances of affected leptomeningeal vessels. The ultrastructural appearances of the vessel wall deposit are illustrated, and their similarity to those of immune complex deposits discussed.

Venous angioma of the facial nerve: a case report.

BACKGROUND: Lower motor neurone type facial nerve palsy is a common condition that is very rarely caused by a neoplastic lesion. CASE DESCRIPTION: This case report describes a progressive facial palsy in a 62-year-old man because of a vascular tumor of the facial nerve. Histologic examination confirmed it to be a venous angioma. CONCLUSION: Meticulous imaging of the facial nerve is required to diagnose cases of progressive facial nerve palsy caused by a neoplastic lesion.

Cerebrovascular responses to pathophysiological insult in diabetic rats.

Diabetes mellitus is associated with altered cerebrovascular responsiveness and this could contribute to the pathology of stroke in diabetic patients. In these studies, we used a model of haemorrhagic stroke (intrastriatal injection of 50 microl blood) to examine subacute perilesional perfusion and blood-brain barrier (BBB) integrity in spontaneously diabetic rats. Volumes of striatal oligaemia (blood flow < 35 ml 100 g(-1) min(-1)) were significantly increased (>300%) in diabetic rats with intrastriatal blood, compared to either non-diabetic rats with blood or control diabetic rats with striatal injection of silicon oil. However, the increase in BBB permeability was both qualitatively and quantitatively similar in diabetic and control rats. Poorer outcomes following haemorrhagic stroke in diabetic patients may thus result from dysfunctional cerebrovascular control, and particularly decreased dilatatory reserve.

Pathology of small vessel stroke.

Disease of small intracerebral vessels is widely assumed to be responsible for the majority of small, deep-seated (lacunar) infarcts and primary intracerebral haemorrhages. Our present, limited understanding of the pathogenesis of these stroke subtypes, which together constitute up to one-third of all strokes, is based on a limited number of detailed pathology studies, supported by clinical, risk factor and imaging data. Further progress using these traditional approaches has been prevented by a variety of largely technical obstacles. It is suggested that advances in our understanding of the genetic basis of established and new animal stroke models, in turn linked to more focused human genetic stroke surveys, may hold the key to further insights.

Chromosome 11q13 abnormalities in human cancer.

Structural abnormalities affecting band q13 of chromosome 11 have been reported in a variety of human tumors, particularly multiple endocrine neoplasia type 1 (MEN1), certain low-grade B-cell neoplasms, and a significant subset of breast and squamous cell carcinomas. The perturbations of the region are also varied, ranging from allele loss and deletions to specific translocations and DNA amplification. Given their clinical relevance in classifying tumors and identifying patients at increased risk, it is important to locate and characterize the genes on which these aberrations impinge. Here we assess the candidate genes identified thus far and the evidence that implicates them in tumorigenesis.

Small centrum ovale infarcts--a pathological study.

There are limited data, mainly clinical and radiological, on small centrum ovale infarcts (SCOIs). From a consecutive series of 159 autopsy brains we identified 12 cases which on gross pathological examination harboured a total of 21 SCOIs. In the majority of lesions histology revealed a significant component of incompletely infarcted brain. Clinicopathological data suggested that the underlying mechanism was likely to have been cardioembolic in 3 cases, and possibly embolic from heart or aortic arch in a further 5. Two cases were due to ipsilateral carotid artery atheroma (i.e. 10 of 12 cases had possible embolic sources). The majority of lesions appeared to lie in arterial borderzones. The combined data suggest that SCOIs are pathologically and pathogenetically heterogeneous, and therefore that the term 'lacune' is inappropriate because this implies intrinsic small vessel disease as the underlying cause. Clinically, potentially treatable cardiac and large vessel pathology should be excluded.

An immunohistochemical study of p53 and proliferating cell nuclear antigen expression in progressive multifocal leukoencephalopathy.

Nuclear p53 immunoreactivity is demonstrated in infected oligodendroglia, as well as in a proportion of reactive and bizarre astrocytes, in seven progressive multifocal leukoencephalopathy (PML) biopsies. This likely represents binding to, and prolongation of the half-life of, wild-type p53 protein by JC virus T-antigen. Other possible mechanisms are considered. The same cells show proliferating cell nuclear antigen (PCNA) positivity, as do a proportion of morphologically normal oligodendroglia and astrocytes, reflecting proliferating populations of these glial sub-types. It is possible that functional inactivation of p53 in nonlytically infected astrocytes may allow neoplastic astrocyte clones to emerge. However, p53 and PCNA immunoreactivity per se cannot be regarded as indicative of neoplasia in PML, and caution must be exercised in the interpretation of such nuclear staining profiles.

Nonhypertensive cerebral small-vessel disease. An autopsy study.

BACKGROUND AND PURPOSE: Cerebral small-vessel disease (SVD) is a common aging phenomenon that is exacerbated by hypertension and diabetes mellitus. It is regarded as an important cause of lacunar infarction and intracerebral hemorrhage. The present study was performed to highlight the existence and to some extent the frequency of pathologically verified SVD lacking in classic risk factors and to extend the scope of risk factor analysis. METHODS: The study group comprised 70 consecutively referred autopsy brains with microscopic evidence of SVD. In each case clinical records, autopsy reports, and central nervous system and systemic autopsy histology were reviewed. SVD was graded as mild, moderate, or severe in six standardized brain regions, and the results analyzed in relation to the presence or absence of classic SVD risk factors. RESULTS: SVD was manifest largely as concentric hyaline wall thickening; lipohyalinosis and fibrinoid necrosis were rarely observed. Thirty-one percent of cases failed to meet stringent clinicopathological criteria for significant prior hypertension. In 9% of cases, patients had been nonelderly, nondiabetic, and normotensive. Five of six cases lacking classic risk factors had systemic conditions known to enhance small-vessel permeability. CONCLUSIONS: The nature of SVD appears to have been modified by effective treatment of hypertension. Classic risk factors are often absent. The hypothesis that a variety of conditions that enhance small-vessel permeability may contribute to the pathogenesis of SVD merits consideration.