Boudewijn Van Damme

Prospective Study on Late Consequences of Subclinical Non-Compliance with Immunosuppressive Therapy in Renal Transplant Patients

In this prospective study we compared the incidence of late acute rejections (LAR) and changes in serum‐creatinine over time between compliers and noncompliers with immunosuppressive therapy more than 1 year post transplantation and explored the relative contribution of non‐compliance and other risk factors in the occurrence of LAR.

Deep intralobular extension of human hepatic 'progenitor cells' correlates with parenchymal inflammation in chronic viral hepatitis: can 'progenitor cells' migrate?

Ductular reaction and putative progenitor cells (or ‘progenitor cells’), which are presumed to be the human counterpart of the oval cells in rat liver, have been discerned in various human liver diseases, including chronic viral hepatitis. Since in experimental models of chronic hepatitis the activation of oval cells is correlated with the inflammatory infiltrate, this study investigated whether there is a correlation in chronic viral hepatitis between the number of ‘progenitor cells’ extending into the lobule and the severity of parenchymal inflammation, on the one hand, and the extent of ductular reaction and the severity of interface hepatitis, on the other hand. Liver biopsies of 55 patients with chronic hepatitis B and/or C were used. The severity of parenchymal inflammation and of interface hepatitis was semiquantitatively graded on a haematoxylin and eosin‐stained paraffin section, while the number of ‘progenitor cells’ and the extent of the ductular reaction were assessed on a serial section stained for cytokeratin (CK) 7. In addition, more extensive phenotyping of ‘progenitor cells’ was performed on sections from frozen material from five patients, using antibodies against CK7, CK8, CK18, CK19, chromogranin‐A, and the rat oval cell marker OV‐6. The number of more centrally located ‘progenitor cells’ correlated significantly with the severity of the parenchymal inflammation, while the extent of the ductular reaction correlated significantly with the severity of interface hepatitis. These findings suggest that in chronic viral hepatitis, inflammation plays a role in ‘progenitor cell’ activation and its topography. In cases with moderate and severe lobular inflammation, ‘progenitor cells’ were strikingly scattered throughout the parenchyma and surrounded by intermediate hepatocyte‐like cells, suggesting their migration into the parenchyma and their differentiation towards the hepatocytic lineage. Copyright

Cytogenetic and fluorescence in situ hybridization investigation of ring chromosomes characterizing a specific pathologic subgroup of adipose tissue tumors

Cytogenetic analysis of 184 adipose tissue tumors, 175 lipomas, and nine liposarcomas (LPS) showed the presence of a ring chromosome and/or a long marker chromosome in 10 cases with common histologic features such as atypical stromal cells with or without lipoblasts. In five of the cases, this appeared to be the sole cytogenetic abnormality. Fluorescence in situ hybridization (FISH) analysis with a microclone library specific for chromosome region 12q13-q15 showed extensive staining of the ring and long marker chromosomes, indicating that genetic sequences of this particular region of chromosome 12 are present in these marker chromosomes, most likely in an amplified form.

MICROSCOPIC VASCULAR INVASION IS THE MOST RELEVANT PROGNOSTICATOR AFTER RADICAL NEPHRECTOMY FOR CLINICALLY NONMETASTATIC RENAL CELL CARCINOMA

PURPOSE Although many factors have been considered to predict the outcome after radical nephrectomy, renal cell carcinoma continues to behave unpredictably. In a retrospective study the correlation between microvascular tumor invasion and disease-free survival after surgery for renal cell carcinoma was analyzed. MATERIALS AND METHODS Between 1980 and 1993, 180 patients (mean age 60 years) were followed for a mean of 52 months after radical or partial nephrectomy for clinically localized renal cell carcinoma. The relevance of microscopic vascular invasion was compared to classical tumor staging, grade and tumor diameter. RESULTS Microscopic vascular invasion was found in 51 patients (28.3%), including 20 (39.2%) with progression (mean interval to progression 72 months). Of 129 patients with no pathological evidence of microscopic vascular invasion only 8 (6.2%) showed progression at a mean interval of more than 160 months. The difference in disease-free survival as a function of microvascular invasion was statistically highly significant (log rank p < 0.00001) and on multivariate analysis this parameter was by far the most relevant predictor of progression. CONCLUSIONS In patients who underwent radical nephrectomy for clinically nonmetastatic renal cell carcinoma with microvascular invasion but without lymph node involvement or macroscopic vascular invasion the chance of disease progression is estimated at 45% within 1 year. Microvascular invasion is the single most relevant prognosticator after presumed curative radical nephrectomy for renal cell carcinoma.

Keratin immunohistochemistry in normal human liver. Cytokeratin pattern of hepatocytes, bile ducts and acinar gradient

A panel of 2 polyclonal and 7 monoclonal antibodies directed against cytokeratins was tested on cryostat and paraffin sections of 14 normal human liver biopsies using an immunoperoxidase procedure. The staining characteristics of hepatocytes and bile ducts are reported. On cryostat sections, monoclonal antibodies directed against individual cytokeratins no8 and no18 stained both bile ducts and hepatocytes, whereas monoclonals anti-cytokeratin no7 and no19 exclusively stained bile ducts. The potential use of these 4 monoclonal antibodies in liver histopathology is briefly discussed. Monoclonal antibody anti-type II cytokeratins and the polyclonal rabbit anti-human keratin stained only bile ducts on both cryostat and paraffin sections. Using monoclonal antibody CAM 5.2 on paraffin sections, both bile ducts and parenchyma were positive. An acinar gradient was apparent in that zone 1 hepatocytes were more intensely stained. Moreover, a rim of hepatocytes around terminal hepatic venules and adjacent to subhepatic veins showed more intense staining. The same gradient could be seen in some paraffin sections stained with the monoclonals anti-cytokeratin no18 and KL1, and the rabbit polyclonal anti-keratin “wide spectrum screening”. The gradient is interpreted as reflecting quantitative differences in keratin content between hepatocytes. Polyclonal rabbit anti-human keratin is proposed as the most reliable antibody for identification of bile ducts in paraffin sections. The usefulness of reliable bile duct staining in several pathological conditions is emphasized.

Donor Age and Renal P-Glycoprotein Expression Associate with Chronic Histological Damage in Renal Allografts

The contributions of donor kidney quality (partially determined by donor age), allograft rejection, and calcineurin inhibitor nephrotoxicity on the progression of histologic damage of renal allografts are not completely defined. Moreover, the determinants of individual susceptibility to calcineurin inhibitor nephrotoxicity are not known but may include variability in drug transport and metabolism. In a prospective cohort of 252 adult renal allograft recipients treated with a combination of tacrolimus, mycophenolate mofetil, and corticosteroids, we studied 744 renal allograft biopsies obtained regularly from time of transplantation for 3 yr. We assessed determinants of histologic evolution, including tacrolimus exposure, renal P-glycoprotein (ABCB1) expression, and polymorphisms in the CYP3A4, CYP3A5, and ABCB1 genes. Within the first 3 yr after transplantation, we noted a progressive increase in interstitial fibrosis, tubular atrophy, glomerulosclerosis, and vascular intimal thickening. Older donor age, absence of P-glycoprotein expression at the apical membrane of tubular epithelial cells, and combined donor-recipient homozygosity for the C3435T variant in ABCB1 significantly associated with increased susceptibility to chronic allograft damage independent of graft quality at implantation. Changes in graft function over time reflected these associations with donor age and ABCB1 polymorphisms, but it was acute T cell-mediated and antibody-mediated rejection that determined early graft survival. In conclusion, the effects of older donor age reach beyond the quality of the allograft at implantation and continue to be important for histologic evolution in the posttransplantation period. In addition, ABCB1 genotype and expression of P-glycoprotein in renal tubular epithelial cells determine susceptibility to chronic tubulointerstitial damage of transplanted kidneys.

The significance of perineural spread in adenoid cystic carcinoma of the major and minor salivary glands.

Patient survival, local recurrence and distant metastasis were studied in relation to the pathological finding of perineural spread in 37 patients with adenoid cystic carcinoma of the major and minor salivary glands. All patients underwent a combined surgical and radiotherapeutical treatment. The overall incidence of perineural invasion in primary resection specimens was 52.6%. The 5-year actuarial survival rate for patients with perineural invasion was significantly lower (p less than 0.001) than for those without (36.9% versus 93.8%). In 26 patients with resection margins free of tumour, recurrences developed in 9/11 (81.8%) of the patients with perineural invasion as opposed to 4/15 (26.7%) of the patients without perineural invasion (p = 0.005). In the same group with resection margins free of tumour, distant metastasis developed after the primary treatment in 4/10 (40.0%) of the patients with perineural invasion, while none of the 14 patients without perineural invasion experienced distant metastasis (p less than 0.0002). The incidence of perineural invasion increased with a higher stage of the primary tumour.

Heparan sulphate proteoglycan expression in human primary liver tumours

Heparan sulphate proteoglycans (HSPGs) play important biological roles in cell–matrix adhesion processes and are essential regulators of growth factor actions (e.g., as co‐receptor for hepatocyte growth factor). Since in liver carcinogenesis, interactions between cells, the matrix, and growth factors play a major role, the aim of this study was to investigate whether the distribution pattern of HSPGs is altered in human primary liver tumours. Twenty‐two primary liver tumours and five normal liver biopsies were studied, using specific monoclonal antibodies against syndecans‐1, ‐2, ‐3, and ‐4; glypican; perlecan; and heparan sulphate chains. Cholangiocarcinomas as well as hepatocellular carcinomas showed an altered immunoreactivity pattern of the different HSPGs in comparison with normal liver parenchyma, probably reflecting the growth regulatory roles of HSPGs. Intracellular positivity for integral membrane HSPGs syndecan‐1 and especially syndecan‐4 was a constant finding in most tumours, suggesting increased synthesis or internalization of these HSPGs. Syndecan‐3 and perlecan expression in tumours was found in an expected distribution pattern. The strong reactivity for syndecan‐3 and perlecan in tumoral stromal vessels might suggest a role for these HSPGs in tumoral angiogenesis. In addition, perlecan probably exerts its known growth factor reservoir function also in the stroma of primary liver tumours.

Inflammatory myofibroblastic tumor of bone: report of two cases with evidence of clonal chromosomal changes.

Inflammatory myofibroblastic tumor (inflammatory pseudotumor) is a pseudosarcomatous lesion that is recognized with increasing frequency in various anatomic locations. However, this lesion has not been previously reported in bone. We report on two cases of inflammatory myofibroblastic tumor occurring in bone in young adults. Both tumors presented as slightly painful, osteolytic, and well-delineated lesions of the distal femur, with a hyperintense signal on T2-weighted magnetic resonance imaging. The patients had an uneventful recovery after curettage. The follow-up time was 11 months for both patients, and no recurrence was noted. On histologic examination, the lesions were characterized by collagen-rich and generally poorly cellular tissue containing spindled to plump (myo)fibroblast-like cells and a variable admixture of inflammatory cells. Focal calcifications and reactive bone formation were present. Clonal, albeit different, chromosomal changes were found in both cases (47,XY,-9,-12,add(21)(q21),+der(?)t(?;9)(?;q11), +mar,+r and 47, XY, +r/47, idem, add(12)(p13)). The present and other reported cytogenetic findings suggest that inflammatory myofibroblastic tumors could well be neoplastic.

Microarray screening for target genes of the proto-oncogene PLAG1

PLAG1 is a proto-oncogene whose ectopic expression can trigger the development of pleomorphic adenomas of the salivary glands and of lipoblastomas. As PLAG1 is a transcription factor, able to activate transcription through the binding to the consensus sequence GRGGC(N)6–8GGG, its ectopic expression presumably results in the deregulation of target genes, leading to uncontrolled cell proliferation. The identification of PLAG1 target genes is therefore a crucial step in understanding the molecular mechanisms involved in PLAG1-induced tumorigenesis. To this end, we analysed the changes in gene expression caused by the conditional induction of PLAG1 expression in fetal kidney 293 cell lines. Using oligonucleotide microarray analyses of about 12 000 genes, we consistently identified 47 genes induced and 12 genes repressed by PLAG1. One of the largest classes identified as upregulated PLAG1 targets consists of growth factors such as the insulin-like growth factor II and the cytokine-like factor 1. The in silico search for PLAG1 consensus sequences in the promoter of the upregulated genes reveals that a large proportion of them harbor several copies of the PLAG1-binding motif, suggesting that they represent direct PLAG1 targets. Our approach was complemented by the comparison of the expression profiles of pleomorphic adenomas induced by PLAG1 versus normal salivary glands. Concordance between these two sets of experiments pinpointed 12 genes that were significantly and consistently upregulated in pleomorphic adenomas and in PLAG1-expressing cells, identifying them as putative PLAG1 targets in these tumors.