The spectrum of somatic mutation of the most aggressive forms of neuroblastoma is not completely determined. We sought to identify potential cancer drivers in clinically aggressive neuroblastoma.Whole exome sequencing was conducted on 17 germline and tumor DNA samples from high-risk patients with adverse events within 36 months from diagnosis (HR-Event3) to identify somatic mutations and deep targeted sequencing of 134 genes selected from the initial screening in additional 48 germline and tumor pairs (62.5% HR-Event3 and high-risk patients), 17 HR-Event3 tumors and 17 human-derived neuroblastoma cell lines.We revealed 22 significantly mutated genes, many of which implicated in cancer progression. Fifteen genes (68.2%) were highly expressed in neuroblastoma supporting their involvement in the disease. CHD9, a cancer driver gene, was the most significantly altered (4.0% of cases) after ALK.Other genes (PTK2, NAV3, NAV1, FZD1 and ATRX), expressed in neuroblastoma and involved in cell invasion and migration were mutated at frequency ranged from 4% to 2%.Focal adhesion and regulation of actin cytoskeleton pathways, were frequently disrupted (14.1% of cases) thus suggesting potential novel therapeutic strategies to prevent disease progression.Notably BARD1, CHEK2 and AXIN2 were enriched in rare, potentially pathogenic, germline variants.In summary, whole exome and deep targeted sequencing identified novel cancer genes of clinically aggressive neuroblastoma. Our analyses show pathway-level implications of infrequently mutated genes in leading neuroblastoma progression.

Paget disease of bone (PDB) is a skeletal disorder characterized by focal abnormalities of bone remodeling, which result in enlarged and deformed bones in one or more regions of the skeleton. In some cases, the pagetic tissue undergoes neoplastic transformation, resulting in osteosarcoma and, less frequently, in giant cell tumor of bone (GCT). We performed whole-exome sequencing in a large family with 14 PDB-affected members, four of whom developed GCT at multiple pagetic skeletal sites, and we identified the c.2810C>G (p.Pro937Arg) missense mutation in the zinc finger protein 687 gene (ZNF687). The mutation precisely co-segregated with the clinical phenotype in all affected family members. The sequencing of seven unrelated individuals with GCT associated with PDB (GCT/PDB) identified the same mutation in all individuals, unravelling a founder effect. ZNF687 is highly expressed during osteoclastogenesis and osteoblastogenesis and is dramatically upregulated in the tumor tissue of individuals with GCT/PDB. Interestingly, our preliminary findings showed that ZNF687, indicated as a target gene of the NFkB transcription factor by ChIP-seq analysis, is also upregulated in the peripheral blood of PDB-affected individuals with (n = 5) or without (n = 6) mutations in SQSTM1, encouraging additional studies to investigate its potential role as a biomarker of PDB risk.

Piwi-associated RNAs (piRNAs) are a distinct class of 24- to 30-nucleotide-long RNAs produced by a Dicer-independent mechanism, and are associated with Piwi-class Argonaute proteins. In contrast to the several hundred species of microRNAs (miRNAs) identified thus far, piRNAs consist of more than 30,000 different species in humans. Studies in flies, fish and mice implicate these piRNAs in regulating germ line development, the silencing of selfish DNA elements, and maintaining germ line DNA integrity. Most piRNAs map to unique sites in the human genome, including intergenic, intronic, and exonic sequences. However, the role of piRNAs in humans remains to be elucidated. Here, we uncover an unexpected function of the piRNA pathway in humans. We show for the first time, that the piRNA_015520, located in intron 1 of the human Melatonin receptor 1A (MTNR1A) gene, is expressed in adult human tissues (testes and brain) and in the human cell line HEK 293. Although the role of piR_015520 expression in brain tissue remains unknown, the testes-specific expression is consistent with previous findings in several species.Surprisingly, in contrast to the mechanism known for miRNA-mediated modulation of gene expression, piRNA_015520 negatively regulates MTNR1A gene expression by binding to its genomic region. This finding suggests that changes in individual piRNA levels could influence both autoregulatory gene expression and the expression of the gene in which the piRNA is located. These findings offer a new perspective for piRNAs functioning as gene regulators in humans.