High endothelial cell proliferation index and high microvessel density in vascular hotspots suggest an active angiogenic process in human colorectal adenocarcinomas. Angiogenesis Group

Enhanced nestin expression and small blood vessels in human pituitary adenomas

The role of angiogenesis in human pituitary tumor progression is questioned. Our aim was to characterize the morphologic changes that occur in the vasculature of pituitary adenomas, in correlation with the expression of nestin, a protein found in endothelial cells of newly formed vessels of developing organs. We also evaluated the relation of angiogenic markers and nestin with Ki-67 index. Immunohistochemical studies were performed on paraffin embedded samples of 47 pituitary adenomas and six normal pituitaries. We determined microvessel density (number of CD31+ or CD34+ vessels per square millimetre), vascular area (cumulative area occupied by vessels), average vessel size, and further classified vessels as small (< 100 μm2) or large (> 100 μm2). We correlated the above parameters with nestin expression and Ki-67 index. Lower vascular area compared to normal tissue was found in adenomas (p < 0.05). Interestingly, pituitary adenomas had significantly more small vessels than control pituitaries (p < 0.04 for CD31 and CD34). In tumors many capillaries were positive for nestin, while scarce staining was detected in controls, so that nestin positive area was significantly higher in tumors. Furthermore, nestin area correlated positively with the % of small vessels. Ki-67 correlated neither with vascular area nor with nestin expression. In human pituitary tumors there was a predominance of small capillaries in correlation with increased expression of the progenitor marker nestin. We suggest that angiogenesis is an active process in these tumors, in spite of their low total vascular area when compared to normal pituitaries.

Vascular diffusion density and survival of patients with primary lung carcinomas

AIM

To investigate the clinical significance of tumour vascularisation in operated lung cancer patients.

MATERIALS AND METHODS

Histological slides obtained from 498 patients with potentially curative operated lung carcinomas in two different institutions of thoracic surgery were immunohistochemically stained with an anti-CD34 antibody and subjected to quantitative image analysis. Syntactic structure analysis measured the absolute and relative features of vessels, including the numerical tumour cells densities relative to their nearest neighbouring vessel. These data are associated with tumour volume, post-surgical TNM stage, and each patient's survival.

RESULTS

The clinical data, including sex distribution, age of patients, pTNM stages and survival, did not differ between the two institutions. The tumour vascularisation (volume fraction, Vv) amounted to 7% in lung carcinomas, was independent from cell type and increased in advanced tumour stages (pT4, pN3). Advanced tumour stages presented with a higher numerical vascular density and with maintained minimum diameter and circumference of vessels. Each patient's survival was closely associated with the pN stage, tumour volume, cell type and numerical density of tumour cells within a distance less than 20 micro m from the nearest neighbouring vessel due to multivariate statistical analysis.

CONCLUSION

Vascularisation of lung tumours becomes altered in advanced tumour stages. Of prognostic significance is the distribution of tumour cells in relation to the nearest neighbouring vessel only.