Hervé Sartelet

Expression of vascular endothelial growth factor (VEGF) and its two receptors (VEGF-R1-Flt1 and VEGF-R2-Flk1/KDR) in non-small cell lung carcinomas (NSCLCs): correlation with angiogenesis and survival.

The formation of new vessels (angiogenesis) is essential for primary tumour growth and metastasis and is induced by several angiogenic factors, including vascular endothelial growth factor (VEGF). The microvascular density (MVD) in tumours was assessed and the expression of VEGF and its receptors VEGF‐R1‐Flt1 and VEGF‐R2‐KDR/Flk1 was investigated in the different cellular compartments in vivo, in order to establish their interrelationship and their prognostic influence. Immunohistochemical study of 69 stage I–II non‐small cell lung carcinomas (NSCLCs) was performed on paraffin sections with CD34 antibody to estimate MVD, using a Chalkley eye‐piece graticule and VEGF, VEGF‐R1, and VEGF‐R2 antibodies. There was strong expression of VEGF and its receptors in tumour cells, endothelial cells, and stromal fibroblasts. In tumour cells, the level of VEGF was correlated with that of VEGF‐R1 ( p = 0·018) but not that of VEGF‐R2. In fibroblasts, high expression of VEGF was correlated with that of VEGF‐R1 ( p = 0·0001) and VEGF‐R2 ( p = 0·0001). In endothelial cells, expression of VEGF was correlated with that of VEGF‐R1 ( p < 0·0001) and VEGF‐R2 ( p = 0·04). The level of VEGF in fibroblasts was correlated with that of VEGF‐R1 ( p = 0·0028) and VEGF‐R2 ( p = 0·01) in endothelial cells. There was no correlation between the level of MVD and that of VEGF or VEGF‐R1 or VEGF‐R2. Neither the level of MVD, nor the level of expression of VEGF and VEGF receptors in any compartment influenced the patients survival. In conclusion, although angiogenesis is essential for tumour growth, this study failed to demonstrate that MVD, VEGF, VEGF‐R1, and VEGF‐R2 are prognostic markers for stage I–II NSCLC. VEGF, however, might act as a direct autocrine growth factor for tumour cells via VEGF‐R1 and angiogenesis could be promoted in a paracrine loop, where VEGF is produced by fibroblasts and tumour cells and then binds to endothelial cells via induced VEGF receptors. VEGF and its receptors thus appear as relevant therapeutic targets in NSCLC. Copyright

Sirolimus-Induced Thrombotic Microangiopathy is Associated with Decreased Expression of Vascular Endothelial Growth Factor in Kidneys

The aim of this study was to examine the clinical characteristics, the histological features and the renal expression of vascular endothelial growth factor (VEGF) of five patients with sirolimus‐associated thrombotic microangiopathy (TMA). Sirolimus‐induced TMA occurs preferentially in kidneys with concomitant endothelial injury: it was observed in three patients with acute cellular rejection on calcineurin inhibitor‐free regimen, in one patient with chronic graft rejection on a calcineurin inhibitor‐free protocol and in one patient with chronic calcineurin inhibitor nephrotoxicity. We found that renal VEGF expression during sirolimus‐induced TMA was significantly lower than VEGF expression in normal transplanted kidneys (p < 0.01). Decreased expression of VEGF seems to be a consequence of sirolimus treatment since (i) analysis of two biopsies performed after the switch of sirolimus to calcineurin inhibitor showed reappearance of VEGF expression, (ii) no decreased expression of VEGF was found in five kidneys with classical TMA and, (iii) an increased expression of VEGF was observed in seven kidneys with acute cellular rejection on a sirolimus‐free immunosuppressive regimen (p < 0.01). The potential role of sirolimus‐induced downregulation of VEGF as a predisposing factor to the development of TMA is discussed.

Detection of N-myc amplification by FISH in immature areas of fixed neuroblastomas: more efficient than Southern blot/PCR.

N‐myc amplification is a major prognostic factor in neuroblastomas and is systematically investigated by Southern blot or polymerase chain reaction (PCR). A retrospective study of N ‐myc amplification has been carried out using fluorescence in situ hybridization (FISH) in 97 fixed neuroblastomas. For each tumour, FISH was performed on the area that contained the most immature neuroblasts. Among these 97 neuroblastomas, 16 were amplified and 12 were not interpretable. FISH was not interpretable in six cases. All neuroblastomas with N‐myc amplification detected by Southern blot/PCR were amplified with FISH, except three that were not interpretable. Four tumours that were not interpretable in Southern blot/PCR contained more than five copies of N‐myc by FISH: one was aneuploid and three were truly amplified, containing more than ten copies of N‐myc. Among these three patients, two died in a short time of their tumours. Ten cases were not amplified by Southern blot/PCR and showed more than five copies by FISH: four were aneuploid and two showed heterogeneous amplification, with a few cells clearly amplified whereas most were not. Four cases were amplified, of which two patients died of their tumours. This study confirms that when applied to the most immature areas of fixed neuroblastomas, FISH displayed a higher sensitivity than molecular techniques (p < 0.001) and could detect heterogeneous amplification. FISH could therefore become an important complementary procedure in assessing prognosis in neuroblastomas. Copyright

Extraosseous Ewing sarcoma with foci of neuroblastoma-like differentiation associated with EWSR1(Ewing sarcoma breakpoint region 1)/FLI1 translocation without prior chemotherapy

Peripheral primitive neuroectodermal tumor/Ewing sarcoma and neuroblastoma are distinct malignant tumors belonging to the group of undifferentiated solid pediatric tumors. We report a case of a 14-year-old adolescent girl who presented with a right lower quadrant mass. At surgery, a mobile retroperitoneal mass was entirely removed. Histologic evaluation revealed 2 distinct components; the first, consisting of sheets of undifferentiated cells, was CD99+ and CD56-, whereas the second, consisting of multiple foci of neuropil and maturing neuroblasts, was CD99- and CD56+. Fluorescence in situ hybridization analysis revealed the presence of EWSR1/FLI1 translocation in both histologic distinct components. MYCN (myelocytomatosis viral related oncogene, neuroblastoma derived) was not amplified. The tests for t(11;22) and t(21;22) performed by reverse transcription-polymerase chain reaction were negative. The final diagnosis corresponds to an extraosseous Ewing sarcoma with foci of neuroblastoma-like differentiation. This is the first case, documented by molecular studies, in which neuroblastoma-like differentiation has been noted in primitive neuroectodermal tumor/Ewing sarcoma without prior chemotherapy.

Quantitative Computer Image Analysis of Chondroitin Sulfate A Expression in Placentas Infected with Plasmodium Falciparum

Most pathological conditions resulting from infection with the human malaria parasite Plasmodium falciparum occur as a consequence of the sequestration by several adhesion molecules of parasite-infected red blood cells (IRBCs). Recent reports have provided evidence that placental vascular endothelial ligands for IRBCs were mostly restricted to chondroitin sulfate A (CSA). The expression of CSA in malaria-infected placentas was investigated in a prospective case-control study in a hypoendemic area (Dakar, Senegal). The tissue distribution of CSA was measured in the terminal villi by immunostaining combined with image processing in 20 infected and 20 noninfected frozen sections of placenta. The villous surface immunostained by anti-CSA antibody was higher in infected than in noninfected placentas (p<0.03), in placentas with active infection than in those with past chronic infection (p<0.05), and in infected placentas with positive imprints than in those with negative imprints (not significant; p=0.06). Labeling was found in the extracellular matrix and in endothelial and stromal cells of all the placentas. Syncytiotrophoblast immunostaining was detected in all placentas associated with active or active chronic infection (n=7) but in only 4/13 placentas with past chronic infection (p<0.01). The presence of P. falciparum in the imprint was significantly correlated with immunostaining of CSA in syncytiotrophoblasts (p=0.003). These results suggest that CSA can play an important role in the sequestration of P. falciparum in human placentas during the acute phase of infection.