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Primary hepatic neuroendocrine tumors (PHNETs) are extremely rare NETs originating from the liver. These tumors are associated with heterogeneous prognosis, and few treatment targets for PHNETs have been identified. Because the major genetic alterations in PHNET are still largely unknown, we performed whole-exome sequencing of 22 paired tissues from PHNET patients and identified 22 recurring mutations of somatic genes involved in the following activities: epigenetic modification (BPTF, MECP2 and WDR5), cell cycle (TP53, ATM, MED12, DIDO1 and ATAD5) and neural development (UBR4, MEN1, GLUL and GIGYF2). Here, we show that TP53 and the SET domain containing the 1B gene (SETD1B) are the most frequently mutated genes in this set of samples (3/22 subjects, 13.6%). A biological analysis suggests that one of the three SETD1B mutants, A1054del, promotes cell proliferation, migration and invasion compared to wild-type SETD1B. Our work unveils that SETD1B A1054del mutant is functional in PHNET and implicates genes including TP53 in the disease. Our findings thus characterize the mutational landscapes of PHNET and implicate novel gene mutations linked to PHNET pathogenesis and potential therapeutic targets., (© 2019 UICC.)

Oesophageal carcinoma is the fourth leading cause of cancer-related death in China, and more than 90% of these tumours are oesophageal squamous cell carcinoma (ESCC). Although several ESCC genomic sequencing studies have identified mutated somatic genes, the number of samples in each study was relatively small, and the molecular basis of ESCC has not been fully elucidated. Here, we performed an integrated analysis of 490 tumours by combining the genomic data from 7 previous ESCC projects. We identified 18 significantly mutated genes (SMGs). PTEN, DCDC1 and CUL3 were first reported as SMGs in ESCC. Notably, the AJUBA mutations and mutational signature4 were significantly correlated with a poorer survival in patients with ESCC. Hierarchical clustering analysis of the copy number alteration (CNA) of cancer gene census (CGC) genes in ESCC patients revealed three subtypes, and subtype3 exhibited more CNAs and marked for worse prognosis compared with subtype2. Moreover, database annotation suggested that two significantly differential CNA genes (PIK3CA and FBXW7) between subtype3 and subtype2 may serve as therapeutic drug targets. This study has extended our knowledge of the genetic basis of ESCC and shed some light into the clinical relevance, which would help improve the therapy and prognosis of ESCC patients.

Bladder cancer (BC) is distinguished by high rate of recurrence after surgery, but the underlying mechanisms remain poorly understood. Here we performed the whole-exome sequencing of 37 BC individuals including 20 primary and 17 recurrent samples in which the primary and recurrent samples were not from the same patient. We uncovered that MLL, EP400, PRDM2, ANK3 and CHD5 exclusively altered in recurrent BCs. Specifically, the recurrent BCs and bladder cancer cells with MLL mutation displayed increased histone H3 tri-methyl K4 (H3K4me3) modification in tissue and cell levels and showed enhanced expression of GATA4 and ETS1 downstream. What's more, MLL mutated bladder cancer cells obtained with CRISPR/Cas9 showed increased ability of drug-resistance to epirubicin (a chemotherapy drug for bladder cancer) than wild type cells. Additionally, the BC patients with high expression of GATA4 and ETS1 significantly displayed shorter lifespan than patients with low expression. Our study provided an overview of the genetic basis of recrudescent bladder cancer and discovered that genetic alterations of MLL were involved in BC relapse. The increased modification of H3K4me3 and expression of GATA4 and ETS1 would be the promising targets for the diagnosis and therapy of relapsed bladder cancer.

We sequenced whole exomes of ten clear cell renal cell carcinomas (ccRCCs) and performed a screen of ∼1,100 genes in 88 additional ccRCCs, from which we discovered 12 previously unidentified genes mutated at elevated frequencies in ccRCC. Notably, we detected frequent mutations in the ubiquitin-mediated proteolysis pathway (UMPP), and alterations in the UMPP were significantly associated with overexpression of HIF1α and HIF2α in the tumors (P = 0.01 and 0.04, respectively). Our findings highlight the potential contribution of UMPP to ccRCC tumorigenesis through the activation of the hypoxia regulatory network.

Transitional cell carcinoma (TCC) is the most common type of bladder cancer. Here we sequenced the exomes of nine individuals with TCC and screened all the somatically mutated genes in a prevalence set of 88 additional individuals with TCC with different tumor stages and grades. In our study, we discovered a variety of genes previously unknown to be mutated in TCC. Notably, we identified genetic aberrations of the chromatin remodeling genes (UTX, MLL-MLL3, CREBBP-EP300, NCOR1, ARID1A and CHD6) in 59% of our 97 subjects with TCC. Of these genes, we showed UTX to be altered substantially more frequently in tumors of low stages and grades, highlighting its potential role in the classification and diagnosis of bladder cancer. Our results provide an overview of the genetic basis of TCC and suggest that aberration of chromatin regulation might be a hallmark of bladder cancer.