[Neuroblastoma: prevalence of genetic alterations in different histological groups].

Abstract

Neuroblastoma is a disease characterized by clinical, histological and genetic heterogeneity. The morphological type, immunohistochemical expression of proteins (MYCN, MYC) and molecular genetic characteristics of the tumor (the status of the MYCN gene and chromosomal regions 1p and 11q) are key to predicting the course of the disease and choosing therapy.

Objective: Estimate the prevalence of the most clinically significant genetic events in different histological groups and among neuroblastomas in general and to demonstrate rarer genetic findings.

Material and methods: A total of 233 cases of patients with neuroblastoma, for whom the histological conclusion and the results of cytogenetic examination by FISH (the status of the MYCN gene and chromosomal regions 1p and 11q) were known, were analyzed. Based on these data, the cases were divided into favorable and unfavorable histological groups, in each of which the presence of genetic abnormalities was analyzed. Also, 28 cases of patients with large cell neuroblastoma were analyzed, for whom the histological conclusion, MYCN gene status, immunohistochemical expression of MYC protein and the results of cytogenetic study of MYC gene status by FISH were known.

Results: MYCN gene amplification, 1p deletion/imbalance and 11q deletion/imbalance are more common in tumors from the unfavorable morphological group. Aberrations of the chromosomal region 1p and MYCN amplification are events that often occur together, while 11q aberrations, on the contrary, have an inverse correlation with MYCN amplification. 11q deletion/imbalance is more often detected in tumors with MYCN gain. In 4 cases, 1p and 11q chromosomal aberrations were detected in the same tumor, all in the unfavorable histological group. Two cases with chromosomal aberrations in stromal cells were also identified. Expression of MYC protein was detected in 5 cases, of which 2 showed amplification of the MYC gene.