Morphological, Immunohistochemical and Genetic Characteristics of Paediatric Renal Tumours in Latvia. Summary of the Doctoral Thesis

Abstract

Paediatric renal tumours represent 7% of all tumours in first 15 years of life. Wilms tumour or nephroblastoma is the most common tumour (85% of cases), followed by renal cell carcinomas (3-5%), mesoblastic nephroma (3%), clear cell sarcoma of the kidney, rhabdoid tumour of the kidney (2%) and miscellaneous rare tumours (2%). The variable and overlapping appearances of the tumours and their rarity make them especially challenging group of lesions for the pathologist. Accurate histological diagnosis and staging of these tumours are critical because their treatment and prognosis are very different too. Currently, the world's pediatric pathologists interest is concentrated upon the research of potentially prognostic important immunohistochemical markers and scientific work is focused on the development of adequate on immunohistochemical findings based scheme of chemotherapy and development of criteria for evaluating the effectiveness of chemotherapy. In the case of nephroblastoma there are studied a lot of potentially prognostic important markers and the data has not yet been clearly interpreted. Prognostic important is p53 protein expression level, which have positive correlation with grade of anaplasia and poor prognosis, while the clinical significance of proliferation index (Ki67/MIB-1) in the case of nephroblastoma is questionable. Some authors describe cadherine group proteins, WT1 protein, angiogenesis markers and CD44 isoform expression association with tumor stage and prognosis. Now there are studied CDKN2A tumor suppressor gene changes localized in chromosome 9p21 and CDKN2A gene encoded p16^INK4a protein expression rate in tumour tissues. There are currently no fundamental studies devoted to morphologic spectrum of children kidney tumours in Baltic countries. Consequently both the expression of potentially prognostic important immunohistochemical markers and genetic changes in tumor tissue are not investigated. Aim of the present paper is to investigate the situation with pediatric renal tumours in Latvia, compare histological appearances before and after immunohistochemistry, to determine diagnostically and prognostically important immunohistochemical markers in tumor tissue, as well as to make molecular genetic investigations of tumours.