Identification of Recurrent 3q13.31 Chromosomal Rearrangement Indicates As a Tumor Suppressor Gene in Neuroblastoma

Neuroblastoma (NB) is a childhood malignancy of the sympathetic nervous system. NB is mainly driven by copy number alterations, such as amplification, large deletions of chromosome arm 11q and gain of chromosome arm 17q, which are all markers of high‑risk disease. Genes targeted by recurrent, smaller, focal alterations include and . Our previous study on relapsed NB detected recurrent structural alterations centered at limbic system‑associated membrane protein (; HUGO Gene Nomenclature Committee: 6705; chromosomal location 3q13.31), which is a gene frequently reported to be deleted or downregulated in other types of cancer. Notably, in cancer, has been shown to have tumor‑suppressing functions. The present study performed an expanded investigation using whole genome sequencing of tumors from 35 patients, mainly with high‑risk NB. Focal duplications or deletions targeting were detected in six cases (17%), whereas single nucleotide polymorphism‑microarray analysis of 16 NB cell lines detected segmental alterations at 3q13.31 in seven out of the 16 NB cell lines (44%). Furthermore, low expression of in NB tumors was significantly associated with poor overall and event‑free survival. , knockdown of in NB cell lines increased cell proliferation, whereas overexpression decreased proliferation and viability. These findings supported a tumor suppressor role for in NB. However, the higher incidence of aberrations in cell lines and in relapsed NB tumors suggested that these alterations were a late event predominantly in advanced NB with a poor prognosis, indicating a role of in tumor progression rather than in tumor initiation. In conclusion, the present study demonstrated recurrent genomic aberrations of chromosomal region 3q13.31 that targeted the gene, which encodes a membrane protein involved in cell adhesion, central nervous system development and neurite outgrowth. The frequent aberrations affecting , together with functional evidence, suggested an anti‑proliferative role of in NB.