{'fraction_non_alphanumeric': 0.01935483870967742, 'fraction_numerical': 0.005955334987593052, 'mean_word_length': 5.675496688741722, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Analysis of microvascular density and the expression of vascular-endothelial growth factor (VEGF) and its membrane receptor Flk-1 in neuroblastoma].

AIM
To assess selected angiogenic markers; microvascular density and the expression of VEGF and Flk-1 in relation to clinical features and morphologic types of neuroblastoma.


PATIENTS AND METHODS
Eighty-two children with neuroblastoma were studied. Morphological assessment was performed in paraffin embedded tissues of the primary tumours. Microvessels within tumour tissue were counted on immunohistochemically stained sections using anti CD34 antibody. The expression of VEGF and Flk-1 was estimated semiquantitively in immunohistochemically stained sections with adequate antibodies. The results of angiogenic studies were referred to the clinical data: age, clinical stage, localization and site of the primary tumour, serum LDH and ferritin at diagnosis. The correlation between angiogenic markers and morphological type of neuroblastoma was also evaluated.


RESULTS
Microvascular density varies in a wide range (32-325/mm(2)). There was no significant statistical difference between previously untreated and tumours assessed after chemotherapy. Analyzing the correlations between the angiogenic markers and clinical features we found a converse relation between the age and microvascular density. The highest expression of VEGF was found in adrenal tumours in comparison to other localizations. Undifferentiated and poorly differentiated tumours presented a higher expression of VEGF and higher vascular density. Non significant higher expression of VEGF and higher vascular density was noticed in smaller <5 cm tumours.


CONCLUSIONS
Correlations were found between the microvascular density and the age, diameter and the localisation of the primary tumour. Expression of VEGF depends on the localisation of the tumour. Neuroblastoma tumours arising in small children and poorly differentiated types of neuroblastoma indicate higher angiogenic activity.