Molecular characterization and survival analysis of a cohort of glioblastoma, IDH-wildtype.

Glioblastoma, IDH-wild type, the most common malignant primary central nervous system tumor, represents a formidable challenge in clinical management due to its poor prognosis and limited therapeutic responses. With an evolving understanding of its underlying biology, there is an urgent need to identify prognostic molecular groups that can be subject to targeted therapy. This study established a cohort of 124 sequential glioblastomas from a tertiary hospital and aimed to find correlations between molecular features and survival outcomes. Comprehensive molecular characterization of the cohort revealed prevalent alterations as previously described, such as TERT promoter mutations and involvement of the PI3K-Akt-mTOR, CK4/6-CDKN2A/B-RB1, and p14ARF-MDM2-MDM4-p53 pathways. MGMT promoter methylation is a significant predictor of improved overall survival, aligned with previous data. Conversely, age showed a marginal association with higher mortality. Multivariate analysis to account for the effect of MGMT promoter methylation and age showed that, in contrast to other published series, this cohort demonstrated improved survival for tumors harboring PTEN mutations, and that there was no observed difference for most other molecular alterations, including EGFR amplification, RB1 loss, or the coexistence of EGFR amplification and deletion/exon skipping (EGFRvIII). Despite limitations in sample size, this study contributes data to the molecular landscape of glioblastomas, prompting further investigations to examine these findings more closely in larger cohorts.

Recurrent TRAK1::RAF1 Fusions in pediatric low-grade gliomas.

Fusions involving CRAF (RAF1) are infrequent oncogenic drivers in pediatric low-grade gliomas, rarely identified in tumors bearing features of pilocytic astrocytoma, and involving a limited number of known fusion partners. We describe recurrent TRAK1::RAF1 fusions, previously unreported in brain tumors, in three pediatric patients with low-grade glial-glioneuronal tumors. We present the associated clinical, histopathologic and molecular features. Patients were all female, aged 8 years, 15 months, and 10 months at diagnosis. All tumors were located in the cerebral hemispheres and predominantly cortical, with leptomeningeal involvement in 2/3 patients. Similar to previously described activating RAF1 fusions, the breakpoints in RAF1 all occurred 5' of the kinase domain, while the breakpoints in the 3' partner preserved the N-terminal kinesin-interacting domain and coiled-coil motifs of TRAK1. Two of the three cases demonstrated methylation profiles (v12.5) compatible with desmoplastic infantile ganglioglioma (DIG)/desmoplastic infantile astrocytoma (DIA) and have remained clinically stable and without disease progression/recurrence after resection. The remaining tumor was non-classifiable; with focal recurrence 14 months after initial resection; the patient remains symptom free and without further recurrence/progression (5 months post re-resection and 19 months from initial diagnosis). Our report expands the landscape of oncogenic RAF1 fusions in pediatric gliomas, which will help to further refine tumor classification and guide management of patients with these alterations.

EGFR and ERBB2 exon 20 insertion/duplication in advanced non-small cell lung cancer: genomic profiling and clinicopathologic features.

Background: Exon 20 (ex20) in-frame insertions or duplications (ins/dup) in epidermal growth factor receptor (EGFR) and its analog erb-b2 receptor tyrosine kinase 2 (ERBB2) are each detected in 1.5% of non-small cell lung cancer (NSCLC). Unlike EGFR p.L858R or ex19 deletions, ex20 ins/dup is associated with de novo resistance to classic EGFR inhibitors, lack of response to immune checkpoint inhibitors, and poor prognosis. US Food and Drug Administration has approved mobocertinib and amivantamab for targeting tumors with this aberration, but the number of comprehensive studies on ex20 ins/dup NSCLC is limited. We identified 18 cases of NSCLCs with EGFR/ERBB2 ex20 ins/dup and correlated the findings with clinical and morphologic information including programed death-ligand 1 (PD-L1) expression. Methods: A total of 536 NSCLC cases tested at our institution between 2014 and 2023 were reviewed. A custom-designed 214-gene next-generation sequencing panel was used for detecting DNA variants, and the FusionPlex CTL panel (ArcherDx) was used for the detection of fusion transcripts from formalin-fixed, paraffin-embedded tissue. Immunohistochemistry (IHC)for PD-L1 was performed using 22C3 or E1L3N clones. Results: Nine EGFR and nine ERBB2 ex20 ins/dup variants were identified from an equal number of men and women, 14 were non- or light smokers, and 15 had stage IV disease. All 18 cases were adenocarcinomas. Seven of the 11 cases with available primary tumors had acinar predominant pattern, two had lepidic predominant pattern, and the remainder had papillary (one case) and mucinous (one case) patterns. Ex20 ins/dup variants were heterogenous in-frame one to four amino acids spanning A767-V774 in EGFR and Y772-P780 in ERBB2 and were clustered in the loop following the C-helix and α C-helix. Twelve cases (67%) had co-existing TP53 variants. Copy number variation in CDK4 amplification was identified in one case. No fusion or microsatellite instability was identified in any case. PD-L1 was positive in two cases, low positive in four cases, and negative in 11 cases. Conclusions: NSCLCs harboring EGFR/ERBB2 ex20 ins/dup are rare and tend to be acinar predominant, negative for PD-L1, more frequent in non- or light smokers, and mutually exclusive with other driver mutations in NSCLC. The correlation of different EGFR/ERBB2 ex20 ins/dup variants and co-existing mutations with response to targeted therapy and the possibility of developing resistant mutations after mobocertinib treatment warrants further investigation.

Genomic Profiling of Metastatic Uveal Melanoma Shows Frequent Coexisting BAP1 or SF3B1 and GNAQ/GNA11 Mutations and Correlation With Prognosis.

OBJECTIVES: To identify therapeutic targets and correlate with clinical outcomes from mutation profiling of metastatic uveal melanoma (UM) using next-generation sequencing (NGS). METHODS: Melanoma cases that were tested using DNA-based NGS panels of 25 and/or 214 genes were evaluated retrospectively (263 cases) and identified 27 UM cases. BAP1 expression was examined by immunohistochemistry. RESULTS: Mutations in GNA11 (14) and GNAQ (12) were found in 96% (n = 27) of cases of UM, and most had coexisting BAP1 (17) or SF3B1 (4) mutations. Coexisting GNAQ/11-SF3B1 mutations correlated with a longer average time to first metastasis compared with GNAQ/11-BAP1 mutations (99.7 vs 38.5 months, P = .047). Three patients with BAP1 mutations received trametinib; two are still alive (15 months; 23 months), and one died (32 months). In non-UMs, only 4.2% (n = 236) had BAP1 and 3.8% had SF3B1 mutations; none had coexisting GNAQ/11 mutations. CONCLUSIONS: Coexisting BAP1/SF3B1 and GNAQ/11 mutations were unique to UM. SF3B1 mutations were reported to be UM-specific in melanoma and associated with rare/no metastasis. The finding of mutated SF3B1 in 14.8% (n = 27) of UMs suggests its role should be further evaluated. The correlation of BAP1/SF3B1 mutation with survival also warrants investigation.

Oncogenic Activity of Solute Carrier Family 45 Member 2 and Alpha-Methylacyl-Coenzyme A Racemase Gene Fusion Is Mediated by Mitogen-Activated Protein Kinase.

Chromosome rearrangement is one of the hallmarks of human malignancies. Gene fusion is one of the consequences of chromosome rearrangements. In this report, we show that gene fusion between solute carrier family 45 member 2 (SLC45A2) and alpha-methylacyl-coenzyme A racemase (AMACR) occurs in eight different types of human malignancies, with frequencies ranging from 45% to 97%. The chimeric protein is translocated to the lysosomal membrane and activates the extracellular signal-regulated kinase signaling cascade. The fusion protein promotes cell growth, accelerates migration, resists serum starvation-induced cell death, and is essential for cancer growth in mouse xenograft cancer models. Introduction of SLC45A2-AMACR into the mouse liver using a sleeping beauty transposon system and somatic knockout of phosphatase and TENsin homolog (Pten) generated spontaneous liver cancers within a short period. Conclusion: The gene fusion between SLC45A2 and AMACR may be a driving event for human liver cancer development.

PTCH1-GLI1 Fusion-Positive Ovarian Tumor: Report of a Unique Case With Response to Tyrosine Kinase Inhibitor Pazopanib.

Recurrent GLI1 gene fusions have been recently described in a subset of soft tissue tumors showing a distinct monotonous epithelioid morphology with a rich capillary network and frequent S100 protein expression. Three different fusion partners-ACTB, MALAT1, and PTCH1-have been reported with the PTCH1-GLI1 fusion from 2 patients only, both with head and neck tumors. Herein, we report for the first time a PTCH1-GLI1 fusion in a primary ovarian tumor from a female patient aged 54 years who presented with a 21-cm right ovarian mass and mesenteric metastasis. The tumor was diagnosed as "favor malignant melanoma" based on histologic examination and extensive immunohistochemistry studies. The patient received 4 cycles of pembrolizumab and 2 cycles of trabectedin but developed multiple metastases. A next-generation sequencing-based assay detected a PTCH1-GLI1 fusion, which led to a revised pathologic diagnosis and a change of the patient's management. The patient was switched to the tyrosine kinase inhibitor (TKI) pazopanib to target the sonic hedgehog pathway. Her disease was stable 49 months post TKI therapy. Our case report is the first to show that a tumor with GLI1 oncogenic activation was sensitive to a TKI. The morphologic and immunohistochemistry similarities of our patient's tumor to other recently described tumors harboring GLI1 fusions suggest that these tumors may all belong to the same entity of GLI1 fusion-positive neoplasms and may be treated similarly.

Validation of Optical Genome Mapping for the Molecular Diagnosis of Facioscapulohumeral Muscular Dystrophy.

The molecular diagnosis of facioscapulohumeral muscular dystrophy (FSHD) relies on detecting contractions of the unique D4Z4 repeat array at the chromosome 4q35 locus in the presence of a permissive 4q35A haplotype. Long, intact DNA molecules are required for accurate sizing of D4Z4 repeats. We validated the use of optical genome mapping to determine size and haplotype of D4Z4 alleles for FSHD analysis. The cohort included 36 unique DNA specimens from fresh blood samples or archived agarose plugs. High-molecular- weight DNA underwent sequence-specific labeling followed by separation and image analysis with data collection on the Saphyr system. D4Z4 allele sizes were calculated and haplotypes determined from the labeling patterns. Each specimen had previous diagnostic testing using restriction enzyme digests with EcoRI, EcoRI/BlnI, XapI, or HindIII, followed by pulsed field gel electrophoresis and Southern blot analysis with appropriate probes. Optical genome mapping detected 4q35 and 10q26 alleles ranging from 1 to 79 D4Z4 repeats and showed strong correlation with Southern blot allele sizing (R2 = 0.95) and haplotyping (133 of 134; 99.4% haplotype match). Analysis of inter-assay and intra-assay runs showed high reproducibility (0.03 to 0.94 %CV). Subsequent optical genome mapping for routine clinical testing from 315 clinical FSHD cases compared favorably with historical result trends. Optical genome mapping is an accurate and highly reproducible method for chromosomal abnormalities associated with FSHD.

Pten-NOLC1 fusion promotes cancers involving MET and EGFR signalings.

Inactivation of Pten gene through deletions and mutations leading to excessive pro-growth signaling pathway activations frequently occurs in cancers. Here, we report a Pten derived pro-cancer growth gene fusion Pten-NOLC1 originated from a chr10 genome rearrangement and identified through a transcriptome sequencing analysis of human cancers. Pten-NOLC1 fusion is present in primary human cancer samples and cancer cell lines from different organs. The product of Pten-NOLC1 is a nuclear protein that interacts and activates promoters of EGFR, c-MET, and their signaling molecules. Pten-NOLC1 promotes cancer proliferation, growth, invasion, and metastasis, and reduces the survival of animals xenografted with Pten-NOLC1-expressing cancer cells. Genomic disruption of Pten-NOLC1 induces cancer cell death, while genomic integration of this fusion gene into the liver coupled with somatic Pten deletion produces spontaneous liver cancers in mice. Our studies indicate that Pten-NOLC1 gene fusion is a driver for human cancers.

Cell cycle progression score has potential prognostic value for stage T1 renal cell carcinomas.

BACKGROUND: There is an ongoing effort to identify a biomarker which predicts metastatic progression of renal cell carcinoma (RCC). OBJECTIVE: To evaluate the utility of the cell cycle progression (CCP) score biomarker in predicting metastasis in RCC after local resection of pathologic T1 disease. DESIGN, SETTING, AND PARTICIPANTS: Pathologic T1 tumors at the University of Iowa were reviewed in patients who had a radical or partial nephrectomy between 1995 and 2010. Patients with known or suspected metastasis, who had received chemotherapy, or who developed metastasis within 60 days of surgery were excluded. Final analysis included 163 patients with RCC who developed metastasis or a new primary within 5 years after surgery or had been followed for 5 years without developing metastasis. INTERVENTION(S): Expression levels of 31 cell cycle genes and 15 control genes from the tumor were measured and reported as a CCP score. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The sensitivity, specificity, positive predictive value, and negative predictive value for the development of a metastasis or new primary within 5 years of resection was calculated for varying CCP score cutoffs. RESULTS AND LIMITATIONS: A total of 4 (2.5%) patients developed metastasis and 7 (4.3%) developed a new primary renal tumor. A CCP score of >-0.25 had a 100% sensitivity and 43% specificity for predicting metastatic progression. A CCP score of >-0.7 had a 100% sensitivity and 20% specificity for predicting the development of a new renal primary. CONCLUSIONS: The CCP score has potential prognostic value in predicting metastatic progression and might be a useful tool for the management of patients with RCC. PATIENT SUMMARY: In this study we looked at the utility of a particular gene expression profile from kidney tumors. We found that this gene expression test has the potential to identify tumors at risk of metastasis and thus could be a useful tool in the management of patients with kidney tumors.

Alpha-dystroglycan staining pattern and mortality in patients undergoing radical prostatectomy with lymph node positive prostate cancer.

INTRODUCTION: Dystroglycan (DG) is a cell surface receptor for extracellular matrix proteins involved in tissue mechanical stability and matrix organization. Initial work has demonstrated that alpha-DG expression is decreased in many types of adenocarcinoma, including prostate, and potentially associated with the development of metastatic disease. However, the consistency between prostate and lymph node alpha-DG staining has not been previously reported. In addition, identification of an immunohistochemical marker associated with prostate cancer grade, stage, need for adjuvant or salvage therapy and mortality would have potential clinical value. MATERIALS AND METHODS: Node positive, margin negative radical prostatectomy specimens at a single institution from 1982 to 2012 were reviewed and identified 35 prostate specimens, including 26 patients with available tissue from both the primary prostatectomy and lymph node specimens. The expression levels of the alpha-DG subunit were analyzed using immunohistochemistry and graded from 0 to 4. Survival was compared in different staining pattern groups. RESULTS: Strength of alpha-DG staining was found to be consistent between prostate and lymph node specimens (p < 0.004). The median overall survival was shorter in those without alpha-DG staining in the prostate compared to those with positive staining, but this difference was not statistically significant (13.2 years versus 19.4 years, p = 0.21). In addition, negative staining was associated with higher mean PSA, pathologic T stage, Gleason grade and the need for adjuvant or salvage therapy compared to positive group but none reached statistical significance (16.06 ng/mL versus 11.67 ng/mL, p = 0.79; 89% versus 68%, p = 0.38; 33.3% versus 23.1%, p = 0.66; 88.9% versus 76.9%, p = 0.44). CONCLUSIONS: DG expression by immunohistochemistry staining was consistent between prostate and metastatic lymph node specimens. In a small cohort of prostate cancer patients with margin negative but node positive disease, DG staining was not associated with Gleason grade or with overall mortality.

Urothelial carcinoma with an NRF1-BRAF rearrangement and response to targeted therapy.

Although BRAF mutations are commonly identified in many solid tumors and the response of BRAF p.V600E-positive tumors to targeted therapy is well documented, BRAF rearrangements are less frequent and are predominantly found in low-grade glioma, melanoma, lung, colorectal, and thyroid carcinoma. Preclinical and clinical studies have demonstrated effectiveness of multiple therapies (RAF-targeted, ERK-targeted, or MEK-targeted) targeting BRAF-fusion harboring tumors. We report a rare NRF1-BRAF fusion with novel breakpoints, identified by next-generation sequencing-based assay, from a 69-year-old man with metastatic urothelial carcinoma (UC) of the renal pelvis and his initial clinical response to a second-generation MEK inhibitor, trametinib, before stopping the medication because of adverse side effects. The NRF1-BRAF fusion has only been reported in a single case of anaplastic pleomorphic xanthoastrocytoma, and BRAF rearrangement has never been reported in UC.

Identification of recurrent fusion genes across multiple cancer types.

Chromosome changes are one of the hallmarks of human malignancies. Chromosomal rearrangement is frequent in human cancers. One of the consequences of chromosomal rearrangement is gene fusions in the cancer genome. We have previously identified a panel of fusion genes in aggressive prostate cancers. In this study, we showed that 6 of these fusion genes are present in 7 different types of human malignancies with variable frequencies. Among them, the CCNH-C5orf30 and TRMT11-GRIK2 gene fusions were found in breast cancer, colon cancer, non-small cell lung cancer, esophageal adenocarcinoma, glioblastoma multiforme, ovarian cancer and liver cancer, with frequencies ranging from 12.9% to 85%. In contrast, four other gene fusions (mTOR-TP53BP1, TMEM135-CCDC67, KDM4-AC011523.2 and LRRC59-FLJ60017) are less frequent. Both TRMT11-GRIK2 and CCNH-C5orf30 are also frequently present in lymph node metastatic cancer samples from the breast, colon and ovary. Thus, detecting these fusion transcripts may have significant biological and clinical implications in cancer patient management.

Biallelic TP53 gain of function mutations in rapidly progressing solid tumors.

Recent studies are discovering TP53 mutations with gain of function (GOF) properties that promote tumorigenesis via a variety of mechanisms. To our knowledge, all reported compound mutations are allelic. We identified two patients with biallelic GOF TP53 mutations in their tumors and a third with allelic compound variants. The correlation with p53 expression was also examined. Genomic DNA was extracted from formalin-fixed, paraffin-embedded tissue and mutational analysis was performed using Ion AmpliSeq™Cancer HotSpot Panel V2. Biallelic GOF mutations (p.R273H and p.R273C) were identified in a 19-year-old male with glioblastoma (allele frequencies 94% and 48%) and a 54-year-old with pT3 penile squamous cell carcinoma (allele frequencies 19% and 27%). Immunohistochemistry showed nuclear accumulation of p53. The third patient, a 62-year-old female with metastatic lung adenocarcinoma, had allelic p.P278S (GOF) and p.R283L (non-GOF) variants at frequencies of 61% but with null staining for p53. Germline testing for Patient 1 confirmed wildtype TP53. No other variants were discovered among the genes tested in these cases. All patients succumbed within two years of diagnosis despite aggressive treatment. In conclusion, implementation of TP53 mutation analysis in clinical practice may predict patient outcome, and inhibition of GOF p53 could represent an attractive target for therapy.

Simultaneous detection of single-nucleotide variant, deletion/insertion, and fusion in lung and thyroid carcinoma using cytology specimen and an RNA-based next-generation sequencing assay.

BACKGROUND: Molecular testing for epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) and ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) fusion is routinely performed in patients with stage IV lung adenocarcinoma to assess their eligibility for targeted therapy. Fine-needle aspiration (FNA)-derived material frequently is the only pathologic material available. The identification of genomic aberrations in thyroid nodules from FNA smears may help stratify cancer risk and spare patients from a second surgery. In the current study, the authors tested nucleic acid extracted from the cytology smears of lung and thyroid carcinomas for simultaneous detection of single-nucleotide variant, insertion/deletion, and gene fusion using an RNA-based next-generation sequencing assay. METHODS: A total of 27 cases (17 lung and 10 thyroid carcinomas, the majority of which had known variants) were tested. Areas of interest were scrapped from stained smears using a scalpel. Total nucleic acid was extracted. Gene fusion and mutational analysis was performed using the Comprehensive Thyroid and Lung FusionPlex Assay. Data were analyzed using the analysis pipeline provided by the vendor. Eleven cases with available formalin-fixed, paraffin-embedded (FFPE) tissue were tested in parallel. RESULTS: Gene fusions were detected in 6 cases; common single-nucleotide variants in EGFR, RAS, and BRAF in 14 cases; and in-frame deletions within EGFR in 3 cases. A concordance rate of 100% was observed between FNA and FFPE tissue. CONCLUSIONS: Cytology preparations can be a reliable source for the detection of both DNA and RNA aberrations. The ability to simultaneously detect multiple types of genomic variants is crucial for patients with advanced cancer and maximizes the usefulness of cytology specimens. Cancer Cytopathol 2018;126:158-69. © 2018 American Cancer Society.

Development of Secondary Acute Myeloid Leukemia in a Pediatric Patient Concurrently Receiving Primary Therapy for Ewing Sarcoma.

Ewing sarcoma is a pediatric bone and soft tissue sarcoma that requires intensive therapy, which can cause secondary malignancies. We present a rare case of early, treatment-related AML in a pediatric patient concurrently receiving primary therapy for Ewing sarcoma. Despite AML-directed therapy, our patient died secondary to complications of hyperleukocytosis. Cytogenetic and mutation profiling of the leukemia cells revealed the DNA-topoisomerase-II-inhibitor-associated t(9;11)(p22;q23) translocation and clonal KRAS and BRAF mutations. This report highlights the importance of monitoring for treatment-related effects in cancer therapy, as well as the need for novel, less toxic approaches in Ewing sarcoma therapy.

Single thyroid tumour showing multiple differentiated morphological patterns and intramorphological molecular genetic heterogeneity.

AIMS: A 49-year-old man presented with a single thyroid tumour that showed a combination of conventional papillary carcinoma, follicular variant of papillary carcinoma, clear cell papillary carcinoma, columnar cell carcinoma and poorly differentiated carcinoma. As all of the morphologies have been associated with papillary carcinoma in the literature, we wished to determine if they contained identical or different molecular abnormalities. METHODS: Targeted next generation sequencing (NGS) of each morphological component and metastases was performed. RESULTS: NGS revealed a BRAF p.K601E mutation in both the clear cell papillary carcinoma and poorly differentiated carcinoma and a KRAS p.G12R mutation in the papillary carcinoma, follicular variant. Two different areas of columnar cell variant were tested, with one showing a KRAS p.G12D mutation but no mutation in the other area. A KRAS p.G12R mutation was seen in the metastatic clear cell variant. Two different lymph nodes had metastatic columnar cell carcinoma, one negative for mutations but the other with a compound KRAS p.G12R and KRAS p.G12V mutation on different alleles. No mutations including BRAF and KRAS were seen in the conventional papillary carcinoma. CONCLUSIONS: Although all of the morphological patterns in this tumour have been reported as having aetiological or other association with one another, there was only partial concordance with their molecular signatures. There was significant molecular discordance, however, even with identical morphologies.

Anchored multiplex PCR for targeted next-generation sequencing reveals recurrent and novel USP6 fusions and upregulation of USP6 expression in aneurysmal bone cyst.

Primary aneurysmal bone cyst (ABC) is a neoplastic process due to recurrent translocations involving the USP6 gene. By fluorescence in situ hybridization, up to 69% of primary ABCs harbored USP6 translocations; no USP6 translocation was found in secondary ABC or giant cell tumor of bone (GCT). GCT can recur locally, metastasize to the lungs in some cases, and rarely undergo malignant transformation. Differentiating primary ABC from its mimics is important for treatment and prognosis. We evaluated USP6 fusion and expression in 13 cases of primary and 1 case of secondary ABC, and 9 cases of GCT using nucleic acid extracted from formalin-fixed, paraffin-embedded tissue and a next generation sequencing (NGS)-based assay. USP6 fusions including 7 novel fusions and USP6 transcripts were identified in all 13 primary ABCs. Nine cases with strong evidence of fusions showed high levels of USP6 transcripts by reverse transcription-PCR (RT-PCR). The remaining four had no detectable USP6 expression by a first-round of RT-PCR but the presence of USP6 transcripts was identified by a second-round, nested PCR. The major fusions were confirmed by RT-PCR followed by Sanger sequencing. No USP6 fusion or transcript was detected in any of the GCTs or the case of secondary ABC by NGS or by two rounds of PCR. All USP6 translocations resulted in fusion of the entire USP6 coding sequence with promoters of the fusion gene leading to upregulation of USP6 transcription, which is likely the underlying mechanism for ABC oncogenesis. © 2016 Wiley Periodicals, Inc.

α3ß1 Integrin Suppresses Prostate Cancer Metastasis via Regulation of the Hippo Pathway.

Existing anticancer strategies focused on disrupting integrin functions in tumor cells or tumor-involved endothelial cells have met limited success. An alternative strategy is to augment integrin-mediated pathways that suppress tumor progression, but how integrins can signal to restrain malignant behavior remains unclear. To address this issue, we generated an in vivo model of prostate cancer metastasis via depletion of α3ß1 integrin, a correlation observed in a significant proportion of prostate cancers. Our data describe a mechanism whereby α3ß1 signals through Abl family kinases to restrain Rho GTPase activity, support Hippo pathway suppressor functions, and restrain prostate cancer migration, invasion, and anchorage-independent growth. This α3ß1-Abl kinase-Hippo suppressor pathway identified α3 integrin-deficient prostate cancers as potential candidates for Hippo-targeted therapies currently under development, suggesting new strategies for targeting metastatic prostate cancer based on integrin expression. Our data also revealed paradoxical tumor suppressor functions for Abl kinases in prostate cancer that may help to explain the failure of Abl kinase inhibitor imatinib in prostate cancer clinical trials. Cancer Res; 76(22); 6577-87. ©2016 AACR.

The NAB2-STAT6 gene fusion in solitary fibrous tumor can be reliably detected by anchored multiplexed PCR for targeted next-generation sequencing.

Solitary fibrous tumor (SFT) is a mesenchymal tumor of fibroblastic origin, which can affect any region of the body. 10-15% of SFTs metastasize and metastatic tumors are uniformly lethal with no effective therapies. The behavior of SFT is difficult to predict based on morphology. Recently, an intrachromosomal gene fusion between NAB2 and STAT6 was identified as the defining driving genetic event of SFT and different fusion types correlated with tumor histology and behavior. Due to the proximity of NAB2 and STAT6 on chromosome 12, this fusion may be missed by fluorescence in-situ hybridization. We evaluated 12 SFTs from 10 patients. All tumors showed strong nuclear staining for STAT6 by immunohistochemistry (IHC). The same formalin-fixed, paraffin-embedded blocks for IHC were used for gene fusion detection by a next-generation sequencing (NGS)-based assay. Targeted RNA fusion sequencing for gene fusions was performed using the Universal RNA Fusion Detection Kit, the Archer(™) FusionPlex(™) Sarcoma Panel and the Ion Torrent PGM, and data were analyzed using the Archer Analysis Pipeline 3.3. All tumors were positive for NAB2-STAT6 fusion. Six types of fusions were detected: NAB2ex4-STAT6ex2, NAB2ex2-STAT6ex5, NAB2ex6-STAT6ex16, NAB2ex6-STAT6ex17, NAB2ex3-STAT6ex18 and NAB2intron6-STAT6Ex17. The NGS findings were confirmed by RT-PCR followed by Sanger sequencing. No STAT6 fusion was detected in selected morphologic mimics of SFT. The assay also allows for detection of novel fusions and can detect NAB2-STAT6 fusions at a single-base resolution.