The restricted view of tumour progression as a multistep process defined by the accumulation of mutations in cancer cells has largely ignored the substantial contribution of the tumour microenvironment to malignancy. Even though the seed and soil hypothesis of Paget dates to 1889, it has been less than two decades since researchers have included the tumour microenvironment in their analyses of tumour progression. What have we recently learned from studying tumour-stroma interactions, and will this help to define new targets for therapy?

Friends or foes - bipolar effects of the tumour stroma in cancer.

Glomerular podocytes are highly specialized cells with a complex cytoarchitecture. Their most prominent features are interdigitated foot processes with filtration slits in between. These are bridged by the slit diaphragm, which plays a major role in establishing the selective permeability of the glomerular filtration barrier. Injury to podocytes leads to proteinuria, a hallmark of most glomerular diseases. New technical approaches have led to a considerable increase in our understanding of podocyte biology including protein inventory, composition and arrangement of the cytoskeleton, receptor equipment, and signaling pathways involved in the control of ultrafiltration. Moreover, disturbances of podocyte architecture resulting in the retraction of foot processes and proteinuria appear to be a common theme in the progression of acquired glomerular disease. In hereditary nephrotic syndromes identified over the last 2 years, all mutated gene products were localized in podocytes. This review integrates our recent physiological and molecular understanding of the role of podocytes during the maintenance and failure of the glomerular filtration barrier.

Cell Biology of the Glomerular Podocyte

Molecular characterization of the tumor microenvironment in breast cancer

The elephant in uremia: Oxidant stress as a unifying concept of cardiovascular disease in uremia

Although genetic susceptibility explains the clustering of multiple sclerosis (MS) cases within families and the sharp decline in risk with increasing genetic distance, it cannot fully explain the geographic variations in MS frequency and the changes in risk that occur with migration. Epidemiological data provide some support for the "hygiene hypothesis," but with the additional proviso for a key role of Epstein-Barr virus (EBV) in determining MS risk. We show that whereas EBV stands out as the only infectious agent that can explain many of the key features of MS epidemiology, by itself the link between EBV and MS cannot explain the decline in risk among migrants from high to low MS prevalence areas. This decline implies that either EBV strains in low-risk areas have less propensity to cause MS, or that other infectious or noninfectious factors modify the host response to EBV or otherwise contribute to determine MS risk. The role of infectious factors is discussed here; in a companion article, we will examine the possible role of noninfectious factors and provide evidence that high levels of vitamin D may have a protective role, particularly during adolescence. The primary purpose of these reviews is to identify clues to the causes of MS and to evaluate the possibility of primary prevention.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/ana.21117

Environmental risk factors for multiple sclerosis. Part I: the role of infection.

Aims: Smooth muscle actin (SMA) positive myofibroblasts have been implicated in tumour invasion; however, acquisition of SMA is not limited to peritumorous fibroblasts and other changes in fibroblasts may be more specifically related to the malignant environment. CD34 is a sialomucin expressed by normal breast fibroblasts but lost in invasive carcinomas. The aim of this study was to establish the relation between CD34 and SMA expression in breast fibroblasts and to analyse whether loss of CD34 is specific for invasive disease. Methods: Immunohistochemistry for CD34 and SMA was performed on 135 cases including 10 normal, 10 fibroadenomas, 40 infiltrating ductal carcinomas, 55 cases of ductal carcinoma in situ (DCIS), and 20 radial scar/complex sclerosing lesions. The relation between staining pattern and histopathological features was recorded as positive, negative, or reduced. Results: Fibroblasts around all normal duct–lobule units and those showing epithelial hyperplasia were CD34 positive and mainly SMA negative. In fibroadenomas, fibroblasts retained CD34 but acquired SMA expression. In contrast, fibroblasts around invasive carcinoma were CD34 positive and SMA negative. In DCIS, loss of CD34 was significantly more frequent in high grade tumours than in low or intermediate grade ones (p Conclusions: These results show that SMA positive myofibroblasts exhibit variable expression of CD34, indicating that these markers are not coordinately controlled. Loss of CD34 is strongly related to the malignant phenotype, in both invasive and preinvasive disease, but is not entirely specific because radial scar fibroblasts and fibroblasts in reactive fibrosis exhibit a similar phenotype. The functional relevance of altered CD34 expression is unclear but the very focal changes implicate local signalling mechanisms probably of epithelial origin.

https://jcp.bmj.com/content/jclinpath/56/4/271.full.pdf

There is more than one kind of myofibroblast: analysis of CD34 expression in benign, in situ, and invasive breast lesions

the eVacement of foot processes represents a simpliBackground. Nephrin recently has been identified as a fication of architecture which demands massive remodputative adhesion molecule, expressed in the glomer- elling of the podocyte intercellular junction, the slit ulus, in which mutations cause congenital nephrotic diaphragm. syndrome of Finnish type. We sought to determine The molecular composition of the podocyte cell‐mawhether expression of nephrin is altered in human trix adhesion complexes has been largely determined glomeruli in patients with acquired nephrotic in recent years, but the composition of the slit diasyndrome. phragm remains surprisingly obscure. It contains the Methods. We performed PCR amplification of nephrin a-splice variant of ZO-1 [3], a protein which in the cDNA, using cDNA previously prepared from single a+ form is a normal constituent of tight junctions. human glomeruli plucked fresh from the surface of However, ultrastructurally and functionally, the slit human renal biopsies. We had available four cases of diaphragm is not a tight junction. Other tight junction nephrotic syndrome (one membranous, three minimal proteins such as cingulin [4] and occludin [5] are not change) and six normal controls. PCR product quant- present, and no other slit diaphragm-associated molecitation was by gel densitometry, confirmed by enzyme- ule has been identified. linked immunosorbent assay using a specific oligonu- The recent identification and sequencing of nephrin cleotide probe. Results were corrected for reaction has, therefore, provoked considerable interest [6 ]. A eYciency and glomerular cellularity by expression as a mutation in the gene for this protein was found to be ratio to levels of the ‘housekeeping gene’ glyceral- the underlying abnormality in the congenital nephrotic dehyde phosphate dehydrogenase. syndrome of Finnish type, where the glomerular podoResults. Glomerular levels of nephrin mRNA are signi- cytes fail to make normal foot processes or slit diaficantly decreased in cases of minimal change nephrotic phragms. Nephrin mRNA is expressed in normal syndrome. An apparent reduction was also seen in the kidneys, and has been localized by in situ hybridization single case of membranous nephropathy which was to the glomerular podocytes of a single human embryo available for study. [6 ]. Sequence analysis suggests that it is a novel Conclusions. Abnormalities of nephrin expression transmembrane adhesion molecule of the immunoglobappear to be associated with acquired as well as ulin superfamily and, therefore, one might speculate congenital causes of human nephrotic syndrome. that it could be a slit diaphragm component.

/pdf/glomerular-expression-of-nephrin-is-decreased-in-acquired-1jq4wp6xny.pdf

Glomerular expression of nephrin is decreased in acquired human nephrotic syndrome.

In normal breast and ductal carcinoma in situ, myoepithelial cells form an incomplete layer separating the epithelial compartment from the stromal environment Transition to invasive disease is marked by penetration of the myoepithelial-basement membrane (BM) interface One mechanism involved in tumour invasion is breakdown of extracellular matrices by matrix metalloproteinases (MMPs) It was hypothesized that myoepithelial cells may modulate tumour invasion by controlling MMP gene expression, both in tumour cells and in peri-ductal fibroblasts To investigate this, myoepithelial cells from normal breast were purified and characterized and their effect on tumour cell invasive potential was assessed The effect on MMP gene expression of breast cancer cells cultured alone or in combination with primary normal breast fibroblasts was also analysed using RT-PCR with ELISA quantitation, with zymographic analysis to measure enzyme activity Normal breast myoepithelial cells significantly reduced invasion by the breast cancer cell lines MCF-7, T47D, MDA-MB 231, and MDA-MB 468 when they were cultured alone or in the presence of a fibroblast population Reduced invasion was associated with changes in MMP gene expression In those tumour cells expressing MMP, there was a significant down-regulation of MMP-2 (MDA-MB 468, p<0001), MMP-9 (MDA-MB 231, p=005; MDA-MB 468, p<0001), and MT1-MMP (p<0001 for both MDA-MB 231 and MDA-MB 468) Myoepithelial cells also caused a significant decrease in MMP gene expression in co-cultured fibroblasts Furthermore, this was associated with reduced gelatinolytic activity as identified by zymography This study demonstrates for the first time that primary myoepithelial cells from normal breast reduce breast cancer cell invasion and that this is mediated via modulation of both tumour cell and fibroblast function This emphasizes the importance of the myoepithelial cell in controlling the breast microenvironment and focuses on the potential significance of the loss of this population with disease progression

Primary breast myoepithelial cells exert an invasion-suppressor effect on breast cancer cells via paracrine down-regulation of MMP expression in fibroblasts and tumour cells

An in situ hybridization technique has been developed for assessing poly(A)+ RNA preservation in routine pathology specimens. The method detects poly-adenylated RNA sequences in tissue sections using a biotinylated polydeoxythymidine (poly d(T)) probe. The probe was prepared from single-stranded 25-30 base oligo d(T) and was biotinylated using the enzyme terminal deoxynucleotide transferase with biotin-11-dUTP and dTTP in the ratio 1:4. The hybridization protocol uses varying concentrations of proteinase K to unmask mRNA sequences and the biotin-labelled hybrids are demonstrated after hybridization under standard conditions by the application of streptavidin and biotinylated alkaline phosphatase. Alkaline phosphatase was visualized using a Fast Red naphthol-capture method and the sections were counterstained with haematoxylin. The results have confirmed that the method is specific for poly(A)+ RNA and shows that poly(A)+ RNA can be demonstrated in routine formalin-fixed sections using non-radioactive techniques with retention of morphology. It also provides a means of optimizing the hybridization conditions for specific mRNA probes and produces a staining pattern demonstrating the relative level of poly(A)+ RNA per cell which may reveal new information about cell activity and tissue function.

In situ hybridization demonstration of poly‐adenylated RNA sequences in formalin‐fixed paraffin sections using a biotinylated oligonucleotide poly d(T) probe

AIM: To investigate the possible role of the systemic IgA immune system in the pathogenesis of IgA nephropathy METHODS: J chain mRNA expression in the IgA cells of the bone marrow was studied. Bone marrow trephine biopsy specimens from seven patients with IgA nephropathy and seven matched controls were examined by (1) non-isotopic in situ hybridisation (ISH) and (2) combined immunofluorescence and non-isotopic ISH to identify the plasma cell type. Serum polymeric IgA was also determined using standard high pressure liquid chromatography and sandwich enzyme linked immunosorbent assay. RESULTS: Non-isotopic ISH revealed a similar number of J chain mRNA positive cells/unit length in biopsy specimens from patients (16.5 +/- 2.7 cells/mm) and controls (17.7 +/- 2.4 cells/mm). Combined immunofluorescence and ISH revealed a greater proportion of J chain mRNA positive IgA cells in patients (7.6 +/- 1.45%) compared with controls (3 +/- 0.8%). Serum polymeric IgA was similar in both patients (91 +/- 22 mg/l) and controls (77 +/- 24 mg/l). CONCLUSION: These data suggest that excess production of dimeric IgA occurs in the bone marrow in IgA nephropathy.

https://jcp.bmj.com/content/jclinpath/49/1/38.full.pdf

J H Pringle

Papers

There is more than one kind of myofibroblast: analysis of CD34 expression in benign, in situ, and invasive breast lesions

Glomerular expression of nephrin is decreased in acquired human nephrotic syndrome.

Primary breast myoepithelial cells exert an invasion-suppressor effect on breast cancer cells via paracrine down-regulation of MMP expression in fibroblasts and tumour cells

In situ hybridization demonstration of poly‐adenylated RNA sequences in formalin‐fixed paraffin sections using a biotinylated oligonucleotide poly d(T) probe

Increased dimeric IgA producing B cells in the bone marrow in IgA nephropathy determined by in situ hybridisation for J chain mRNA.