Neuroblastoma (NB) is a common
malignancy in children but rarely occurs during adolescence or adulthood. This subgroup is characterized by an indolent disease course, almost uniformly fatal, yet little is known about the
biologic characteristics. The aim of this study was to identify differential features regarding
DNA copy number alterations, α-
thalassemia/
mental retardation syndrome X-linked (
ATRX) protein expression, and the presence of
tumor-associated inflammatory cells. Thirty-one NB patients older than 10 years who were included in the Spanish NB Registry were considered for the current study; seven young and middle-aged adult patients (range 18-60 years) formed part of the cohort. We performed single nucleotide polymorphism arrays, immunohistochemistry for
immune markers (CD4, CD8, CD20, CD11b, CD11c, and CD68), and
ATRX protein expression. Assorted genetic profiles were found with a predominant presence of a segmental
chromosome aberration (SCA) profile. Preadolescent and adolescent NB
tumors showed a higher number of SCA, including 17q gain and 11q deletion. There was also a marked infiltration of immune cells, mainly high and heterogeneous, in young and middle-aged adult
tumors. ATRX negative expression was present in the
tumors. The characteristics of preadolescent, adolescent, young adult, and middle-aged adult NB
tumors are different, not only from childhood NB
tumors but also from each other. Similar examinations of a larger number of such
tumor tissues from cooperative groups should lead to a better older age-dependent
tumor pattern and to innovative, individual risk-adapted therapeutic approaches for these patients.