Platelet-derived endothelial cell growth factor/thymidine phosphorylase immunohistochemical expression in lymphoid tissue and lymphoid malignancies

Expression of thymidine phosphorylase in lymph nodes involved with mycosis fungoides and sézary syndrome

Thymidine phosphorylase may be overexpressed in both neoplastic cells and tumor stromal cells in a variety of malignancies. Our study explores thymidine phosphorylase expression in lymph nodes (LNs) from patients with mycosis fungoides (MF) or Sézary syndrome (SS). In MF/SS, the LNs may have a pathologic diagnosis of either dermatopathic lymphadenopathy (LN-DL) or involvement by MF/SS (LN-MF). We performed immunohistochemical staining on MF/SS lymph nodes using antibodies to thymidine phosphorylase, CD68, CD21, CD3, and CD4. In both LN-DL and benign nodes, thymidine phosphorylase staining was noted only in macrophages, dendritic cells, and endothelial cells. In LN-MF, thymidine phosphorylase expression was also noted in subsets of intermediate to large neoplastic T cells. Concurrent CD68, CD21, CD3, and CD4 staining supported the above observations. Similar results were noted in the skin and in LN-MF with large cell transformation. Other T-cell lymphomas were also examined (total 7 cases); only enteropathy-type T-cell lymphoma (1 case) showed TP positivity in neoplastic T lymphocytes. We demonstrated that thymidine phosphorylase staining is present in neoplastic T cells in mycosis fungoides. The exact mechanism needs further investigation.

Micro-vessel density and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PdEGF) in classical Hodgkin lymphoma (HL)

There is little information to date regarding the role of angiogenesis in Hodgkin lymphoma (HL). The present study examines micro-vessel density and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial growth factor (PdEGF) in lymph node biopsies of patients with HL at presentation and relapse. Using immunohistochemistry, the degree of new blood vessel formation and the expression of VEGF and PdEGF was assessed in Hodgkin-rich tissue. The micro-vessel density (MVD) increased with disease progression in seven out of 11 cases. Expression of VEGF was observed in endothelial cells (EC) of some micro-vessels and also in follicular dendritic cells. The Hodgkin/Reed-Sternberg (H-RS) cells as well as the inflammatory lymphocytes were negative for VEGF. Cytoplasmic or cytoplasmic and nuclear expression of PdEGF by the H-RS cells was observed in five of the 11 presentation cases. The expression of PdEGF increased with disease progression in seven cases. In conclusion, Hodgkin tissue shows prominent vascularization. The increased MVD and PdEGF expression with disease progression merits further investigation.

Topoisomerase IIalpha expression as an independent prognostic factor in Hodgkin's lymphoma

PURPOSE

To correlate the immunohistochemical expression of topoisomerase IIalpha (topoIIalpha) in Hodgkin's lymphoma (HL) with clinicopathological parameters, the expression of Ki-67 and the outcome of patients, who had been homogenously treated with ABVD or equivalent regimens.

EXPERIMENTAL DESIGN

Immunohistochemistry using the monoclonal antibody Ki-S1 (topoIIalpha) was performed in 238 HL patients. MiB1 (Ki-67) expression was evaluated in 211/238.

RESULTS

The mean +/- SD percentage of topoIIalpha- and Ki-67-positive Hodgkin-Reed-Sternberg (HRS) cells was 63 +/- 19% (5%-98%) and 73 +/- 19% (8%-99%), respectively. The median percentage of topoIIalpha-positive HRS cells was 64% (interquartile range, 51-78%). There was no correlation between topoIIalpha expression and patient characteristics. TopoIIalpha and Ki-67 expression were correlated (Spearman's Rho 0.255, P < 0.001). TopoIlalpha expression within the highest quartile of this patient population was predictive of failure free survival (FFS) (10-year rates 82 +/- 3% vs 68 +/- 7%, P = 0.02 for patients falling into the quartiles 1-3 and 4 respectively). In multivariate analysis topoIIalpha expression was independently predictive of FFS.

CONCLUSION

TopoIIalpha was expressed in all cases of HL showing a correlation with Ki-67 expression. Under current standard therapy including drugs inhibiting its activity, topoIIalpha was an independent adverse predictor of FFS with no statistically significant correlation with other established prognostic factors.

Vascular patterns in reactive lymphoid tissue and in non-Hodgkin's lymphoma

The few studies published on angiogenesis in lymphoma have raised the question of whether or not microvessel density (MVD) is associated with more aggressive disease and have reported the observation that in follicular lymphomas, vessels are mature rather than immature. We investigated MVD and the vascular phenotype within follicular or diffuse large B-cell lymphomas, reactive nodes and tonsils. Vascular phenotype was defined by the expression or loss of reactivity to the antibody LH39 (detecting the LH39 laminin epitope of the basement membrane in mature vessels) and by detection of alpha V beta 3 (expressed on immature vessels). In reactive nodes and in follicular lymphomas, MVD was higher in the paracortex than in germinal centres or in neoplastic follicles. However, in neoplastic follicles an increase in alpha V beta 3-positive endothelium suggested the activation of an angiogenic pathway different from that present in the reactive follicles. In large B-cell lymphomas, MVD was higher than in reactive and neoplastic follicles but lower than in the reactive paracortex. The number of immature vessels (LH39 negative) and of alpha V beta 3-positive vessels was higher than in reactive lymph nodes and follicular lymphoma suggesting that a switch to a different angiogenic pathway has occurred. Finally, we have demonstrated that within reactive and neoplastic follicles vascular regression is occurring, perhaps constraining the growth of reactive follicles alongside other phenomena such as apoptosis. Vascular regression was previously believed to occur in adults only in ovarian and endometrial tissue. We conclude that different types of angiogenesis are present in follicular lymphomas and large B-cell lymphomas. This has implications for possible future therapies.

Vascular endothelial growth factor (VEGF) is expressed by neoplastic Hodgkin-Reed-Sternberg cells in Hodgkin's disease

Vascular endothelial growth factor (VEGF) is involved in tumour angiogenesis, an important process for the growth and metastatic potential of solid tumours. Numerous studies have demonstrated up-regulation of VEGF at both mRNA and protein level in various tumours and a correlation with advanced stage and prognosis has been demonstrated in some cases. Limited information exists about its role in lymphoid malignancies and in particular, Hodgkin's disease. The present study examined the immunohistochemical expression of VEGF using the monoclonal antibody VG1 in a series of 61 cases of Hodgkin's disease, including both classical Hodgkin's disease and the nodular lymphocyte predominance variant, and correlated these results with microvessel density, using an anti-CD31 monoclonal antibody. In 41 cases (70.6%) of classical Hodgkin's disease and one of the three cases of nodular lymphocyte predominance Hodgkin's disease, the neoplastic Reed-Sternberg and Hodgkin cells expressed VEGF. The staining observed was cytoplasmic, either diffuse or with a focal paranuclear distribution. Macrophages were always positive, while reactive lymphocytes showed occasional positivity. A variable amount of strong extracellular staining was also observed in the tissue stroma and intravascular plasma staining was prominent. There was no statistically significant relationship between VEGF expression and the subtype of Hodgkin's disease or microvessel density. In vitro studies using the Reed-Sternberg cell lines L428 and KM-H2 were also performed in both normoxia and hypoxia and VEGF protein production was assessed by flow cytometry (FACS), immunoassay of cell culture supernatant, and RT-PCR. Analysis by FACS demonstrated a subset of cells in both cell lines reacting with VG1 and analysis of secreted VEGF (pg/ml per 1x10(6) cells) in cell culture supernatant confirmed the normoxic production in both cell lines and significant hypoxic induction (p<0.005). Additionally, both cell lines expressed VEGF mRNA, as demonstrated using the RT-PCR method. In conclusion, neoplastic cells express VEGF in Hodgkin's disease, as is the case in solid tumours, and this expression may be induced by hypoxia. The presence of VEGF in reactive macrophages and in the extracellular matrix might facilitate tumour progression.

Fibroblast growth factors are translocated to the nucleus of human endothelial cells in a microtubule- and lysosome-independent pathway

Exogenous acidic and basic fibroblast growth factors undergo rapid nuclear translocation in human umbilical vein endothelial cells. When nuclear translocation reaches saturation, more than 70% of the internalized growth factors are in the nuclear fraction. Lysosomal inhibitors, such as leupeptin and chloroquine, and microtubule inhibitors including colchicine and 2-methoxyl-beta-estradiol neither increase nor decrease nuclear translocation. The results suggest that nuclear translocation of fibroblast growth factors does not require cytosolic accumulation or lysosomal processing and that the transportation of exogenous growth factors across the cytoplasm is independent of microtubules.

Thymidine phosphorylase, 2-deoxy-D-ribose and angiogenesis

Angiogenesis is the term used to describe the formation of new blood vessels from the existing vasculature. In order to attract new vessels, a tissue must release an endothelial-cell chemoattractant. 2-Deoxy-D-ribose is produced in vivo by the catalytic action of thymidine phosphorylase (TP) on thymidine and has recently been identified as an endothelial-cell chemoattractant and angiogenesis-inducing factor. TP, previously known only for its role in nucleotide salvage, is now known to be angiogenic. TP expression is elevated in many solid tumours and in chronically inflamed tissues, both known areas of active angiogenesis. There is evidence that TP is also involved in physiological angiogenesis such as endometrial angiogenesis during the menstrual cycle. The majority of known endothelial-cell chemoattractants are polypeptides that bind to endothelial-cell-surface receptors. In contrast, 2-deoxy-D-ribose appears to lack a cell-surface receptor. Glucose is another sugar that acts as an endothelial-cell chemoattractant. The migratory activity of glucose is blocked by ouabain. It is possible that 2-deoxy-D-ribose and glucose stimulate endothelial-cell migration via a similar mechanistic pathway.