Impact of somatic mutations and transcriptomic alterations on cancer aneuploidy

Aneuploidy has been recognized as one of hallmark of tumorigenesis since the early 20th century. Recent developments in structural variation analysis in the human genome have revealed the diversity of aneuploidy in cancer. However, the effects of gene mutation and expression in tumors on aneuploidy remain poorly understood. Here, we performed whole exome analysis of over 5,000 Japanese cancer cases and investigated the impact of somatic mutations and gene expression alterations on aneuploidy. First, we evaluated tumor content and genomic alterations that could influence aneuploidy. Next, we compared the aneuploidy frequency in 18 cancer types and observed that TP53 mutations were associated with the aneuploidy on specific chromosomes in colorectal and gastric cancers. Finally, we used expression analysis to isolate pathways involved in aneuploidy accumulation from tumors without TP53 mutations. Chromosomal instability and cell cycle aberration were associated with aneuploidy in TP53 wild-type tumors, and 26 commonly upregulated genes were identified in aneuploidy-high solid tumors without TP53 mutations. Among them, two cancer-related genes (CENPA and PBK) were involved in aneuploidy. Our integrated analysis revealed that both TP53 mutations and transcriptomic alterations independent of somatic mutations affect aneuploidy accumulation. Our findings will facilitate further understanding of diverse aneuploidies in the tumorigenesis.

Tumor cell enrichment by tissue suspension enables detection of mutations with low variant allele frequency and estimation of germline mutations

Targeted sequencing offers an opportunity to select specific drugs for cancer patients based on alterations in their genome. However, accurate sequencing cannot be performed in cancers harboring diffuse tumor cells because of low tumor content. We performed tumor cell enrichment using tissue suspension of formalin-fixed, paraffin-embedded (FFPE) tissue sections with low tumor cell content. The enriched fractions were used to efficiently identify mutations by sequencing a target panel of cancer-related genes. Tumor-enriched and residual fractions were isolated from FFPE tissue sections of intestinal and diffuse gastric cancers harboring diffuse tumor cells and DNA of suitable quality was isolated for next-generation sequencing. Sequencing of a target panel of cancer-related genes using the tumor-enriched fraction increased the number of detectable mutations and variant allele frequency. Furthermore, mutation analysis of DNA isolated from tumor-enriched and residual fractions allowed us to estimate germline mutations without a blood reference. This approach of tumor cell enrichment will not only enhance the success rate of target panel sequencing, but can also improve the accuracy of detection of somatic mutations in archived specimens.

Mutational concordance analysis provides supportive information for double cancer diagnosis

Background

Mutation analysis using next-generation sequencing highlights the features of tumors with somatic alterations. However, the mutation profile of double cancer remains unclear. Here, we analyzed tumors derived from the same patient using whole exome sequencing (WES) to investigate the coherence of somatic mutations in double cancer.

Methods

First, the tumor mutational burden (TMB) was investigated using WES of 5521 tumor specimens from a Japanese pan-cancer cohort. The frequencies of mutation concordance were then compared in these cancers. Finally, we calculated the expected value of mutational concordance fitting a Poisson distribution to determine the relationship between double and metastatic cancers.

Results

In all, 44, 58, and 121 paired samples were diagnosed as double cancer, multifocal lesions (derived from identical tissues), and metastasis, respectively. Our analysis revealed that common somatic mutations were almost entirely absent in double cancer, whereas primary tumors and metastatic foci harbored several identical alterations. Concordance of the mutation profile in the same patient reflects the tumor origin and development, suggesting the potential for identifying double cancer based on common somatic mutations. Furthermore, according to a Poisson distribution, double cancer could be discriminated based on paired samples from the same patient. The probability of double cancer with more than 10 mutations was ≤1 part-per-billion (ppb, 10^− 9). In multifocal lesions, 74% of tumor pairs accumulated ≤10 common mutations, implying a difference in tumor origin within identical tissues.

Conclusions

These findings indicate that counting common somatic mutations can indicate the differences in origin between tumors derived from the same patient. Our mutation coherence analysis can thus provide beneficial information for diagnosing double cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07899-1.

Determination of Lycopene Concentration in Fresh Tomatoes by Spectrophotometry: A Collaborative Study

BACKGROUND

Lycopene has been the object of considerable research attention recently, and the effects of the intake of lycopene, or of tomato products, have been studied in various ways. In Japan, interest in the health-promoting function of food components has increased.

OBJECTIVE

Developing a method to determine lycopene contents in tomato that meets the Japanese Agricultural Standard (JAS).

METHOD

In the proposed JAS method, the test sample consists of fresh tomatoes; a hexane-acetone mixture is utilized as the extraction solvent. A collaborative study was conducted to evaluate the interlaboratory performance of the method.

RESULTS

Ten laboratories participated and analyzed six test materials characterized by a lycopene content between 39 and 170 mg/kg as blind duplicates. After removing statistical outliers, RSDr ranged from 1.2 to 3.0% and RSDR ranged from 2.4 to 4.2%. The HorRat values were calculated and found to be in the 0.26-0.49 range.

CONCLUSIONS

The method for determining the lycopene content in tomato was evaluated by means of a collaborative study, and the reproducibility of this method was found to be acceptable.

HIGHLIGHTS

Intended for standardization in Japan, a method to determine lycopene content in tomato has been developed and shown to have acceptable precision in a collaborative study.

Over-expression of Caj1, a plasma membrane associated J-domain protein in Saccharomyces cerevisiae, stabilizes amino acid permeases

Hsp70: J-domain protein (JDP) machines, along with the cellular protein degradation systems play a central role in regulating cellular proteostasis. An equally robust surveillance system operates at the plasma membrane too that affects proper sorting, stability as well as the turnover of membrane proteins. Although plausible, a definitive role of the Hsp70: JDP machine in regulating the stability of plasma membrane proteins is not well understood in Saccharomyces cerevisiae. Here we show that a moderate over-expression of Caj1, one of the thirteen JDPs residing in the nucleo-cytosolic compartment of S. cerevisiae reduced the cold sensitivity of tryptophan auxotrophic yeast cells by stabilizing tryptophan permeases, Tat1 and Tat2 in a J-domain dependent manner. Concomitantly, higher Caj1 levels also caused slow growth and increased plasma membrane damage at elevated temperatures possibly due to the stabilization of thermolabile plasma membrane proteins. Finally, we show that although majorly cytosolic, Caj1 also co-localizes with the membrane dye FM4-64 at the cellular periphery suggesting that Caj1 might interact with the plasma membrane. Based on the results presented in this study, we implicate the Hsp70: Caj1 chaperone machine in regulating the stability or turnover of plasma membrane proteins in budding yeast.

Characterization of tumors with ultralow tumor mutational burden in Japanese cancer patients

Tumor mutational burden analysis using whole‐exome sequencing highlights features of tumors with various mutations or known driver alterations. Cancers with few changes in the exon regions have unclear characteristics, even though low‐mutated tumors are often detected in pan‐cancer analysis. In the present study, we analyzed tumors with low tumor mutational burden listed in the Japanese version of The Cancer Genome Atlas, a data set of 5020 primary solid tumors. Our analysis revealed that detection rates of known driver mutations and copy number variation were decreased in samples with tumor mutational burden below 1.0 (ultralow tumor), compared with those in samples with low tumor mutational burden (≤5 mutations/Mb). This trend was also observed in The Cancer Genome Atlas data set. In the ultralow tumor mutational burden tumors, expression analysis showed decreased TP53 inactivation and chromosomal instability. TP53 inactivation frequently correlated with PI3K/mTOR‐related gene expression, implying suppression of the PI3K/mTOR pathway in ultralow tumor mutational burden tumors. In common with mutational burden, the T cell‐inflamed gene expression profiling signature was a potential marker for prediction of an immune checkpoint inhibitor response, and some ultralow tumor mutational burden tumor populations highly expressed this signature. Our analysis focused on how these tumors could provide insight into tumors with low somatic alteration that are difficult to detect solely using whole‐exome sequencing.

North Atlantic climate far more predictable than models imply

Quantifying signals and uncertainties in climate models is essential for the detection, attribution, prediction and projection of climate change^1-3. Although inter-model agreement is high for large-scale temperature signals, dynamical changes in atmospheric circulation are very uncertain⁴. This leads to low confidence in regional projections, especially for precipitation, over the coming decades^5,6. The chaotic nature of the climate system^7-9 may also mean that signal uncertainties are largely irreducible. However, climate projections are difficult to verify until further observations become available. Here we assess retrospective climate model predictions of the past six decades and show that decadal variations in North Atlantic winter climate are highly predictable, despite a lack of agreement between individual model simulations and the poor predictive ability of raw model outputs. Crucially, current models underestimate the predictable signal (the predictable fraction of the total variability) of the North Atlantic Oscillation (the leading mode of variability in North Atlantic atmospheric circulation) by an order of magnitude. Consequently, compared to perfect models, 100 times as many ensemble members are needed in current models to extract this signal, and its effects on the climate are underestimated relative to other factors. To address these limitations, we implement a two-stage post-processing technique. We first adjust the variance of the ensemble-mean North Atlantic Oscillation forecast to match the observed variance of the predictable signal. We then select and use only the ensemble members with a North Atlantic Oscillation sufficiently close to the variance-adjusted ensemble-mean forecast North Atlantic Oscillation. This approach greatly improves decadal predictions of winter climate for Europe and eastern North America. Predictions of Atlantic multidecadal variability are also improved, suggesting that the North Atlantic Oscillation is not driven solely by Atlantic multidecadal variability. Our results highlight the need to understand why the signal-to-noise ratio is too small in current climate models¹⁰, and the extent to which correcting this model error would reduce uncertainties in regional climate change projections on timescales beyond a decade.

Outcome of maintenance systemic chemotherapy with drug-free interval for metastatic urothelial carcinoma

OBJECTIVE

Aiming to achieve long-term disease control, maintenance systemic chemotherapy (MSC) with a 1-3-month drug-free interval is continued in selected patients. We report our experience of MSC for metastatic urothelial carcinoma (UC).

METHODS

Of 228 metastatic UC patients treated with systemic chemotherapy, 40 (17.5%, 40/228) had continuously undergone MSC. Data on the regimen, cycle number, and reason for the discontinuation of MSC were also collected. We analyzed OS from the initiation of MSC until death or the last follow-up, using the log-rank test to assess the significance of differences.

RESULTS

The median number of cycles of chemotherapy was 6, and the responses were CR in 6, PR in 20, SD in 13, and PD in 1 before MSC. Gemcitabine plus CDDP or carboplatin was mainly performed as MSC (70%, 28/40). MSC was repeated quarterly in 30 (75%, 30/40), every two months in 8 (20%, 8/40), and with other intervals in 2 (5%, 2/40). Overall, a median of 3.5 cycles (range: 1-29) of MSC was performed. The reason for the discontinuation of MSC was PD in 24 (60%, 24/40), favorable disease control in 9 (22.5%, 9/40), and myelosuppression in 3 (7.5%, 3/40), and for other reasons in 2 (5%, 2/40). MSC was ongoing in 2 (5%, 2/40). The median OS was 27 months from the initiation of MSC. PS0 (P = 0.0169), the absence of lung metastasis (P = 0.0387), and resection of the primary site (P = 0.0495) were associated with long-term survival after MSC.

CONCLUSIONS

In selected patients, long-term systemic chemotherapy could be performed with a drug-free interval. Our maintenance strategy with cytotoxic drugs may become one of the treatment options for long-term disease control.

Japanese version of The Cancer Genome Atlas, JCGA, established using fresh frozen tumors obtained from 5143 cancer patients

This study aimed to establish the Japanese Cancer Genome Atlas (JCGA) using data from fresh frozen tumor tissues obtained from 5143 Japanese cancer patients, including those with colorectal cancer (31.6%), lung cancer (16.5%), gastric cancer (10.8%) and other cancers (41.1%). The results are part of a single-center study called "High-tech Omics-based Patient Evaluation" or "Project HOPE" conducted at the Shizuoka Cancer Center, Japan. All DNA samples and most RNA samples were analyzed using whole-exome sequencing, cancer gene panel sequencing, fusion gene panel sequencing and microarray gene expression profiling, and the results were annotated using an analysis pipeline termed "Shizuoka Multi-omics Analysis Protocol" developed in-house. Somatic driver alterations were identified in 72.2% of samples in 362 genes (average, 2.3 driver events per sample). Actionable information on drugs that is applicable in the current clinical setting was associated with 11.3% of samples. When including those drugs that are used for investigative purposes, actionable information was assigned to 55.0% of samples. Germline analysis revealed pathogenic mutations in hereditary cancer genes in 9.2% of samples, among which 12.2% were confirmed as pathogenic mutations by confirmatory test. Pathogenic mutations associated with non-cancerous hereditary diseases were detected in 0.4% of samples. Tumor mutation burden (TMB) analysis revealed 5.4% of samples as having the hypermutator phenotype (TMB ≥ 20). Clonal hematopoiesis was observed in 8.4% of samples. Thus, the JCGA dataset and the analytical procedures constitute a fundamental resource for genomic medicine for Japanese cancer patients.

Utility of synthetic MRI in predicting the Ki-67 status of oestrogen receptor-positive breast cancer: a feasibility study

AIM

To evaluate the utility of synthetic magnetic resonance imaging (MRI) of the breast in predicting the Ki-67 status in patients with oestrogen receptor (ER)-positive breast cancer.

MATERIALS AND METHODS

Forty-nine patients with 50 histopathologically proven breast cancers who underwent additional synthetic MRI were enrolled in the present study. Using synthetic MRI images, T1 and T2 relaxation times and their standard deviations (SD) in the breast lesions before (T1-Pre, T2-Pre, PD-Pre, SD of T1-Pre, SD of T2-Pre, SD of PD-Pre) and after (T1-Gd, T2-Gd, PD-Gd, SD of T1-Gd, SD of T2-Gd, SD of PD-Gd) contrast agent injection were obtained. These quantitative values were compared between the low Ki-67 expression (<14%) lesions (low-proliferation group: n=23) and high Ki-67 expression (≥14%) lesions (high-proliferation group: n=27).

RESULTS

The univariate analysis showed that the SD of T1-Gd (p<0.001) and T2-Gd (p=0.042) were significantly higher in the high-proliferation group than in the low-proliferation group. Multivariate analysis further showed that the SD of T1-Gd was a significant and independent predictor of Ki-67 expression, with an area under the receiver operating characteristic (AUROC) curve of 0.885. The sensitivity, specificity, and accuracy of the SD of T1-Gd with an optimal cut-off value of 98.5 were 77.8%, 87%, and 82%, respectively.

CONCLUSION

The SD of T1-Gd obtained from synthetic MRI was useful to predict Ki-67 status.

Driver gene alterations and activated signaling pathways toward malignant progression of gastrointestinal stromal tumors

Mutually exclusive KIT and PDGFRA mutations are considered to be the earliest events in gastrointestinal stromal tumors (GIST), but insufficient for their malignant progression. Herein, we aimed to identify driver genes and signaling pathways relevant to GIST progression. We investigated genetic profiles of 707 driver genes, including mutations, gene fusions, copy number gain or loss, and gene expression for 65 clinical specimens of surgically dissected GIST, consisting of six metastatic tumors and 59 primary tumors from stomach, small intestine, rectum, and esophagus. Genetic alterations included oncogenic mutations and amplification‐dependent expression enhancement for oncogenes (OG), and loss of heterozygosity (LOH) and expression reduction for tumor suppressor genes (TSG). We assigned activated OG and inactivated TSG to 27 signaling pathways, the activation of which was compared between malignant GIST (metastasis and high‐risk GIST) and less malignant GIST (low‐ and very low‐risk GIST). Integrative molecular profiling indicated that a greater incidence of genetic alterations of driver genes was detected in malignant GIST (96%, 22 of 23) than in less malignant GIST (73%, 24 of 33). Malignant GIST samples groups showed mutations, LOH, and aberrant expression dominantly in driver genes associated with signaling pathways of PI3K (PIK3CA, AKT1, and PTEN) and the cell cycle (RB1, CDK4, and CDKN1B). Additionally, we identified potential PI3K‐related genes, the expression of which was upregulated (SNAI1 and TPX2) or downregulated (BANK1) in malignant GIST. Based on our observations, we propose that inhibition of PI3K pathway signals might potentially be an effective therapeutic strategy against malignant progression of GIST.

Pro-gastrin-releasing peptide as a marker for the Ewing sarcoma family of tumors

BACKGROUND

Pro-gastrin-releasing peptide (ProGRP) is an established tumor marker of small cell lung cancer. The purpose of this study was to determine if ProGRP could serve as a tumor marker for the Ewing sarcoma family of tumors (ESFTs).

METHODS

Sixteen patients with ESFTs (mean age 32 years) were included in this study. As a control group, 42 patients with other tumor types that clinically or pathologically mimic ESFTs were also analyzed. Pre-treatment serum ProGRP and neuron-specific enolase (NSE) levels, the relationships between these levels, and tumor volume were investigated. In addition, serial changes in the serum or plasma ProGRP (6 patients) and NSE levels (5 patients) were measured over the course of treatment.

RESULTS

Pre-treatment serum ProGRP levels were higher than the normal range in 8 of 16 patients; for these eight patients, ProGRP levels positively correlated with tumor volume (R = 0.99). In the control group, ProGRP levels were within the normal range, except for the two patients. Changes in ProGRP levels during treatment were consistent with tumor volume. Serum NSE levels were elevated in 14 of 16 patients with ESFTs and 8 of 42 patients with other tumor types. The range of NSE elevation was much smaller compared to that of ProGRP. Our data indicate that ProGRP is superior to NSE in terms of specificity.

CONCLUSIONS

Serum ProGRP levels were elevated in half of the patients with ESFTs and reflected therapeutic response. ProGRP is a reliable tumor marker for the diagnosis of ESFTs and evaluation of treatment response.

Abstract 2721: Establishment of a catalog of somatic genetic alterations of Japanese cancer patients across multiple tumor types at Shizuoka Cancer Center

Background: Recent progression of systematic tumor-molecular profiling study centered on genome sequencing have elucidated molecular signature underlying each tumor type. Tumor molecular profiling enables efficient identification of somatic genetic alterations as potential therapeutic targets. In January 2014, the Shizuoka Cancer Center of Japan launched Project HOPE, which is the first prospective molecular profiling study centered on genome sequencing across multiple tumor types in Japan. Herein, we describe the distributions of the tumor mutation burden (TMB; number of mutations/Mb), genetic alterations frequency, mutational signature across tumor types, and their associations with tissue of origin, histological type, carcinogenic factors, and ethnicity.

Methods: Between January 2014 and January 2017, 3,163 tumor samples from 3,011 patients who underwent surgery at the Shizuoka Cancer Center were collected with informed consent and subjected to whole-exome sequencing (WES) with an Ion Proton system. Corresponding peripheral blood samples were also subjected to WES for identification of tumor-specific genetic alterations. Oncogenic fusions were detected by targeted RNA sequencing. Among them, data of 2,126 primary tumor samples obtained from 2,091 patients without neoadjuvant chemotherapy and/or radiation therapy were selected for this study.

Results: The principal tumor types of ≥40 primary tumors were as follows (N, TMB): colon adenocarcinoma (COAD; 459, 3.6), rectal adenocarcinoma (READ; 366, 3.1), lung adenocarcinoma (LUAD; 290, 1.7), stomach adenocarcinoma (STAD; 221, 3.0), hepatocellular carcinoma (HCC; 112, 3.6), head and neck squamous cell carcinoma (HNSC; 112, 2.8), breast invasive ductal carcinoma (IDC; 82, 1.1), lung squamous cell carcinoma (LUSC; 81, 5.9). Approximately 8.9% of the samples (154 / 1,723) showed a high mutation burden above the threshold defined by the TMB distribution in each principal tumor type, and the mutation signature was related to a defect of DNA repair and exposure to environmental mutagens. In comparison of distribution of TMB in each tumor type between TCGA and this study, some differences in TMB distribution were observed, including LUAD, LUSC, and IDC. In gene mutations based on OncoKB site (October 2018), level 1 or 2 of somatic gene mutation was frequently observed in glioma (84.6%), gastrointestinal stromal tumor (77.4%), melanoma (40.0%), and LUAD (40.0%).

Conclusions: This established catalog of somatic genetic alterations across multiple tumor types in Japanese cancer patients can contribute as benchmark to clinical-trial design with the aim of expanding the number of patients suitable for molecular-targeted therapies in Japan. Based on these data, we are planning clinical trials of molecular-targeted therapies for patients with solid tumor harboring gene alterations.

Citation Format: Hirotsugu Kenmotsu, Masakuni Serizawa, Takeshi Nagashima, Keiichi Ohshima, Keiichi Hatakeyama, Yuji Shimoda, Shumpei Ohnami, Koji Maruyama, Tohru Mochizuki, Yasuto Akiyama, Takashi Sugino, Kenichi Urakami, Masatoshi Kusuhara, Ken Yamaguchi. Establishment of a catalog of somatic genetic alterations of Japanese cancer patients across multiple tumor types at Shizuoka Cancer Center [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2721.

Mutational burden and signatures in 4000 Japanese cancers provide insights into tumorigenesis and response to therapy

Tumor mutational burden (TMB) and mutational signatures reflect the process of mutation accumulation in cancer. However, the significance of these emerging characteristics remains unclear. In the present study, we used whole‐exome sequencing to analyze the TMB and mutational signature in solid tumors of 4046 Japanese patients. Eight predominant signatures—microsatellite instability, smoking, POLE, APOBEC, UV, mismatch repair, double‐strand break repair, and Signature 16—were observed in tumors with TMB higher than 1.0 mutation/Mb, whereas POLE and UV signatures only showed moderate correlation with TMB, suggesting the extensive accumulation of mutations due to defective POLE and UV exposure. The contribution ratio of Signature 16, which is associated with hepatocellular carcinoma in drinkers, was increased in hypopharynx cancer. Tumors with predominant microsatellite instability signature were potential candidates for treatment with immune checkpoint inhibitors such as pembrolizumab and were found in 2.8% of cases. Furthermore, based on microarray analysis, tumors with predominant signatures were classified into 2 subgroups depending on the expression of immune‐related genes reflecting differences in the immune context of the tumor microenvironment. Tumor subpopulations differing in the content of infiltrating immune cells might respond differently to immunotherapeutics. An understanding of cancer characteristics based on TMB and mutational signatures could provide new insights into mutation‐driven tumorigenesis.

Comparative proteomic analysis identifies exosomal Eps8 protein as a potential metastatic biomarker for pancreatic cancer

Exosomes are small vesicles found in extracellular environments including blood, urine, and cell culture medium. Their contents are cell‑type specific, and molecules embedded in exosomes can be useful fluid‑based clinical biomarkers. To identify proteins with metastatic marker potential, we conducted a comparative exosomal proteome analysis using human pancreatic cancer cell lines derived from metastasis, ascites, and primary tumors. Metastatic potential of cell lines was assessed by migratory and invasive activities. A pancreatic cancer cell line from metastasis (SU.86.86) revealed 23‑fold and 20‑fold increases in cell migratory and invasive activities, respectively, compared to the MIA PaCa‑2 cell line derived from primary tumor cells. Liquid chromatography‑mass spectrometry‑based proteome analysis and subsequent validation by immunoblot analysis revealed that epidermal growth factor receptor pathway substrate 8 (Eps8) was highly abundant in exosomes from metastasis‑derived SU.86.86 cells. Comparison of 12 pancreatic cancer cell lines derived from different stages of malignancy revealed a strong relationship between exosomal Eps8 protein levels and cell motile activities (migration: r=0.85, P=4.2x10‑4; invasion: r=0.60, P=3.2x10‑2). Conversely, relationships between intracellular Eps8 protein levels and cell motile activities were moderate (migration: r=0.65, P=2.0x10‑2; invasion: r=0.51, P=9.2x10‑2). It was therefore concluded that exosomal Eps8 protein levels were correlated with the migratory cell potential of human pancreatic cancer cells, indicating that exosomal Eps8 has the potential to be a metastatic biomarker for human pancreatic cancer.

Long-term Survival in a Kidney Transplantation Patient With Progressive Multifocal Leukoencephalopathy: A Case Report

Post-kidney transplantation progressive multifocal leukoencephalopathy (PML) is a rare disease on which there are very few published reports on record. PML is a demyelinating disease caused by a destructive infection of the oligodendrocytes by the JC polyomavirus. No effective therapeutic protocol has been established other than measures to revive the immune function by reducing or discontinuing the administration of immunosuppressive agents. Most cases are progressive and show a poor prognosis. We herein report a case in which renal function has been maintained for 2 years following the onset of PML, which was initially diagnosed 3 years after kidney transplantation.

Tumor mutational burden analysis of 2,000 Japanese cancer genomes using whole exome and targeted gene panel sequencing

Tumor mutational burden (TMB) is an emerging characteristic in cancer and has been associated with microsatellite instability, defective DNA replication/repair, and response to PD-1 and PD-L1 blockade immunotherapy. When estimating TMB, targeted panel sequencing is performed using a few hundred genes; however, a comparison of TMB results obtained with this platform and with whole exome sequencing (WES) has not been performed for various cancer types. In the present study, we compared TMB results using the above two platforms in 2,908 solid tumors that were obtained from Japanese patients. For next-generation sequencing, we used fresh-frozen tissue specimens. The Ion Proton System was employed to detect somatic mutations in the coding genome and to sequence an available cancer panel that targeted 409 genes. We then selected 2,040 samples with sufficient tumor cellularity for TMB analysis. In tumors with TMB-high (TMB ≥ 20 mutations/Mb), TMB derived from WES correlated well with the estimated TMB (eTMB) based on panel sequencing, whereas TMB in the remaining tumors showed a weak correlation. In particular, eTMB was overestimated in tumors with low-frequency mutations, resulting in the accumulation of EGFR mutations not being discriminated as a feature of lung cancer with low-frequency mutations. The eTMB in tumors harboring POLE mutations and microsatellite instability was not overestimated, suggesting that panel sequencing could accurately estimate TMB in tumors with high-frequency mutations such as hypermutator tumors. These results may provide helpful information for interpreting TMB results based on clinical sequencing using a targeted gene panel.

Itching in a trichophytin contact dermatitis mouse model and the antipruritic effect of antifungal agents

BACKGROUND

Tinea is an infectious disease by dermatophytes, of which Trichophyton species accounts for the overwhelming majority of case. Tinea often causes itching with inflammation. In terms of pruritus by fungal infection, however, tinea has not been investigated sufficiently to date.

AIM

To evaluate itch caused by Trichophyton infection and the effect of antifungal agents on the infection, by measuring scratch behaviour and profiles of inflammatory cytokines and chemokines.

METHODS

We used a previously established mouse model of contact hypersensitivity induced by trichophytin, a crude extract from Trichophyton mentagrophytes. Scratching behaviour was recorded using a counting device that measured an electric current induced in a coil by movement of magnets that had been inserted into the hind paws of each animal. We investigated expression of various genes in lesional skin of mice and in normal human epidermal keratinocytes. We also investigated the antipruritic effects of the corticosteroid dexamethasone (DEX) and three antifungal agents: ketoconazole (KCZ), terbinafine (TBF) and liranaftate (LNF).

RESULTS

Biphasic peaks of scratching were observed at 1 h and at 6-7 h during an observation period of 14 h after trichophytin induction. For lesional skin, RNA was extracted 24 h after trichophytin challenge, and increased expression was seen in the genes for interleukin (IL)-17A, interferon-γ, tumour necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-2 and Dectin-1, whereas there was no obvious change in the genes for IL-31 and prostaglandin (PG)E2. Furthermore, KCZ inhibited histidine decarboxylase (HDC) expression in vitro and in vivo, and inhibited scratching in the very early phase. LNF inhibited expression of thymic stromal lymphopoietin (TSLP) and IL-8 in vitro, and TSLP, TNF-α, IL-1α and MIP2 in vivo, and also scratching in the early phase. TBF did not induce any significant alterations in either gene expression or scratching. DEX suppressed expression of all the chemical mediators except HDC in vitro and in vivo, and inhibited scratching.

CONCLUSION

Antifungals can inhibit itching induced by fungal infection through different mechanisms.

Abstract 3422: Genomic landscape of Japanese cancer patients across multiple tumor types: Prospective molecular profiling study of 3,022 patients at Shizuoka Cancer Center

Background: Cancer genome sequencing enables efficient identification of genetic alterations as potential therapeutic targets, representing a fundamental component of precision oncology to make therapeutic decisions based on individualized genetic signatures. In January 2014, the Shizuoka Cancer Center of Japan launched Project HOPE, which is the first prospective molecular profiling study centered on genome sequencing across multiple tumor types. Herein, we describe the distributions of the tumor mutation burden (TMB; number of mutations/Mb), genetic alterations frequency, mutational signature across tumor types, and their associations with tissue of origin, histological type, and carcinogenic factors.

Methods: Between January 2014 and April 2017, 3,174 tumor samples from 3,022 patients who underwent surgery at the Shizuoka Cancer Center were collected with informed consent and subjected to whole-exome sequencing (WES) with an Ion Proton system. Corresponding peripheral blood samples were also subjected to WES for identification of tumor-specific genetic alterations. Oncogenic fusions were detected by targeted RNA sequencing. Samples with estimated tumor purity &lt; 20% were excluded because of the risk of false negatives, leaving 2,899 samples (91%) in the final analysis.

Results: Overall, 2,642 samples were derived from the primary tumor, with a median TMB of approximately 2.7. The principal tumor types of ≥40 primary tumors were as follows (N, TMB): colorectal adenocarcinoma (CRAD; 905, 3.3), lung adenocarcinoma (LUAD; 324, 1.6), gastric adenocarcinoma (GAD; 272, 3.0), head and neck squamous cell carcinoma (HNSC; 164, 2.6), breast invasive ductal carcinoma (BIDC; 138, 1.1), hepatocellular carcinoma (HCC; 124, 3.6), lung squamous cell carcinoma (LUSC; 79, 5.6), and gastrointestinal stromal tumor (GIST; 41, 0.7). Approximately 7.8% of the samples (160/2,047) showed a high mutation burden above the threshold defined by the TMB distribution in each principal tumor type, and the mutation signature was related to a defect of DNA repair and exposure to environmental mutagens. Dominant oncogenic pathways based on the profile of genetic alterations in each tumor type were as follows: Wnt (CRAD), receptor tyrosine kinase (LUAD, GIST), TP53 (GAD, HNSC, LUSC), PI3K (BIDC), and chromatin modification (HCC). GIST was the tumor type with the highest proportion of clinically actionable genetic alterations, followed by BIDC and LUAD.

Conclusions: This is the first report of a prospective genome sequencing analysis across multiple tumor types in Japan. The resulting mutational profile can provide a landscape of commonalities and differences in genetic profiles among tumor types in Japanese patients with cancer, and can contribute to planning a basket study for expanding the patients suitable for treatment with molecular-targeted drugs.

Citation Format: Masakuni Serizawa, Takeshi Nagashima, Keiichi Ohshima, Keiichi Hatakeyama, Yuji Shimoda, Shumpei Ohnami, Kouji Maruyama, Takashi Sugino, Tohru Mochizuki, Yasuto Akiyama, Kenichi Urakami, Masatoshi Kusuhara, Medical staff and experimental staff of the Shizuoka Cancer Center, Ken Yamaguchi. Genomic landscape of Japanese cancer patients across multiple tumor types: Prospective molecular profiling study of 3,022 patients at Shizuoka Cancer Center [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3422.

Molecular profiling and sequential somatic mutation shift in hypermutator tumours harbouring POLE mutations

Defective DNA polymerase ε (POLE) proofreading leads to extensive somatic mutations that exhibit biased mutational properties; however, the characteristics of POLE-mutated tumours remain unclear. In the present study, we describe a molecular profile using whole exome sequencing based on the transition of somatic mutations in 10 POLE-mutated solid tumours that were obtained from 2,042 Japanese patients. The bias of accumulated variations in these mutants was quantified to follow a pattern of somatic mutations, thereby classifying the sequential mutation shift into three periods. During the period prior to occurrence of the aberrant POLE, bare accumulation of mutations in cancer-related genes was observed, whereas PTEN was highly mutated in conjunction with or subsequent to the event, suggesting that POLE and PTEN mutations were responsible for the development of POLE-mutated tumours. Furthermore, homologous recombination was restored following the occurrence of PTEN mutations. Our strategy for estimation of the footprint of somatic mutations may provide new insight towards the understanding of mutation-driven tumourigenesis.

Abstract 380: Systematic identification of novel functional tumor-specific mutations in receptor tyrosine kinases based on their pan-cancer mutational profiles in Japanese patients with cancer

Background: Recent accumulation of large amounts of cancer genome information has revealed the presence of tumor-specific mutations with unknown functions; characterization of these mutations should facilitate the identification of novel therapeutic targets. Some tumor-specific mutations in receptor tyrosine kinases (RTKs) act as oncogenic drivers in multiple cancer types. Here, we aimed to identify novel, functional, tumor-specific, single nucleotide variants (SNVs) in cancer-related RTKs based on pan-cancer mutational profiles in Japanese patients with cancer.

Methods: Surgically resected tissue and corresponding peripheral blood samples of 1,685 patients enrolled in Project HOPE (High-tech Omics-based Patient Evaluation), an ongoing prospective molecular profiling study at the Shizuoka Cancer Center, collected between January 2014 and December 2015, were subjected to whole-exome sequencing with an ion torrent proton platform. Newly detected tumor-specific SNVs that could represent functional mutations between the transmembrane and kinase domains of 35 cancer-related RTKs were subjected to serum response element (SRE)-reporter assay to assess effects on extracellular signal-regulated kinase (ERK) signaling relevant to cancer cell survival.

Results: We identified 201,422 nonsynonymous tumor-specific SNVs in 1,685 patients. Of these SNVs, 1,049 were observed in our focused 35 cancer-related RTKs. Approximately 45% of patients with lung squamous cell carcinoma, which was the most frequent cancer type, followed by lung adenocarcinoma (39%), harbored tumor-specific SNVs in RTKs. The relative frequencies of tumor-specific SNVs in RTKs in other tumor types were 32%, 31%, 29%, 28%, and 19% in liver cancer, colorectal cancer, gastric cancer, head and neck cancer, and breast cancer, respectively. After filtering out of SNVs registered in multiple cancer-related databases, such as COSMIC, dbSNP, and DoCM, to select putative novel tumor-specific SNVs, 22 SNVs were selected as novel tumor-specific SNVs with high potential as functional mutations through an additional selection process based on amino acid substitution patterns and multiple alignment of amino acid residues coupled with information regarding functional mutations. Among these SNVs, 13 had already been assessed using an SRE reporter assay. We identified two SNVs in NTRK1 and IGF1R that were involved in activation of the ERK pathway, indicating that these SNVs may be activating mutations. Moreover, inactivating mutations were also identified. Nine SNVs in FLT3, NTRK1, EPHA5, ERBB4, FGFR3, and KDR significantly reduced ERK activity.

Conclusions: A systematic evaluation of functionally unknown tumor-specific SNVs detected in cancer genome sequencing is necessary to expand the range of molecularly targeted cancer therapeutics.

Citation Format: Masakuni Serizawa, Takeshi Nagashima, Yuji Shimoda, Shumpei Ohnami, Sumiko Ohnami, Keiichi Ohshima, Tohru Mochizuki, Takashi Nakajima, Kenichi Urakami, Masatoshi Kusuhara, Ken Yamaguchi. Systematic identification of novel functional tumor-specific mutations in receptor tyrosine kinases based on their pan-cancer mutational profiles in Japanese patients with cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 380. doi:10.1158/1538-7445.AM2017-380

Multi-omics Profiling of Patients with Melanoma Treated with Nivolumab in Project HOPE

BACKGROUND

Project HOPE (High-tech Omics-based Patient Evaluation) has been in progress since 2014 and uses whole-exome sequencing (WES) and gene expression profiling (GEP). Among a total of 1,685 patients with cancer, 13 with melanoma were registered and characterized using multi-omics analyses to investigate specific biomarkers in responders to programmed cell death-1 (PD-1) blockade.

MATERIALS AND METHODS

The patients with melanoma comprised of six males and seven females, and their mean age was 68 years. Five patients were treated with nivolumab, and two were responders.

RESULTS

GEP analysis demonstrated that PD-L1 expression was positive in for cases, and melanoma-associated antigens and tumor signaling-associated genes were up-regulated in tumor compared with normal tissues. Additionally, WES analysis indicated more single nucleotide variants (SNVs) per melanoma tumor compared to other tumor types. Remarkably, a case of complete remission after nivolumab therapy showed high expression of PD-L1 protein and the highest number of SNVs.

CONCLUSION

The novel approach used in Project HOPE might be an efficient tool that facilitates identifying specific biomarkers predictive of good responders to anti-PD-1 therapy.

FUT2 non-secretor status is associated with Type 1 diabetes susceptibility in Japanese children

AIM

To examine the contribution of the FUT2 gene and ABO blood type to the development of Type 1 diabetes in Japanese children.

METHODS

We analysed FUT2 variants and ABO genotypes in a total of 531 Japanese children diagnosed with Type 1 diabetes and 448 control subjects. The possible association of FUT2 variants and ABO genotypes with the onset of Type 1 diabetes was statistically examined.

RESULTS

The se2 genotype (c.385A>T) of the FUT2 gene was found to confer susceptibility to Type 1A diabetes in a recessive effects model [odds ratio for se2/se2, 1.68 (95% CI 1.20-2.35); corrected P value = 0.0075].

CONCLUSIONS

The FUT2 gene contributed to the development of Type 1 diabetes in the present cohort of Japanese children.

Comprehensive characterization of genes associated with the TP53 signal transduction pathway in various tumors

The TP53 signal transduction pathway is an attractive target for cancer treatments. In this study, we conducted a comprehensive molecular evaluation of 907 patients with cancer in Japan to identify genomic alterations in the TP53 pathway. TP53 mutations were frequently detected in many cancers, except melanoma, thymic tumors, gastrointestinal stromal tumors, and renal cancers. The frequencies of non-synonymous single nucleotide variants (SNVs) in the TP53 family members TP63 and TP73 were relatively low, although genes with increased frequencies of SNVs were as follows: PTEN (11.7%) in breast cancer, CDKN2A (11.1 and 9.6%) in pancreas and head and neck cancers, and ATM (18.0 and 11.1%) in liver and esophageal cancers. MDM2 expression was decreased or increased in patients with mutant or wild-type TP53, respectively. CDKN1A expression was increased with mutant TP53 in head and neck cancers. Moreover, TP63 overexpression was characteristically observed in squamous cell carcinomas of the lung, esophagus, and head and neck region. Additionally, overexpression of TP63 and TP73 was frequently observed in thymomas. Our results reveal a spectrum of genomic alterations in the TP53 pathway that is characteristic of many tumor types, and these data may be useful in the trials of targeted therapies.

Optimizing an ion semiconductor sequencing data analysis method to identify somatic mutations in the genomes of cancer cells in clinical tissue samples

Identification of causal genomic alterations is an indispensable step in the implementation of personalized cancer medicine. Analytical methods play a central role in identifying such changes because of the vast amount of data produced by next generation sequencer. Most analytical techniques are designed for the Illumina platform and are therefore suboptimal for analyzing datasets generated by whole exome sequencing (WES) using the Ion Proton System. Accurate identification of somatic mutations requires the characterization of platform-dependent error profiles and genomic properties that affect the accuracy of sequence data as well as platform-oriented optimization of the pipeline. Therefore, we used the Ion Proton System to perform WES of DNAs isolated from tumor and matched control tissues of 1,058 patients with cancer who were treated at the Shizuoka Cancer Center Hospital. Among the initially identified candidate somatic single-nucleotide variants (SNVs), 10,279 were validated by manual inspection of the WES data followed by Sanger sequencing. These validated SNVs were used as an objective standard to determine an optimum cutoff value to improve the pipeline. Using this optimized pipeline analysis, 189,381 SNVs were identified in 1,101 samples. The analytical technique presented here is a useful resource for conducting clinical WES, particularly using semiconductor-based sequencing technology.

Immune response-associated gene analysis of 1,000 cancer patients using whole-exome sequencing and gene expression profiling-Project HOPE

Project HOPE (High-tech Omics-based Patient Evaluation) has been progressing since its implementation in 2014 using whole-exome sequencing (WES) and gene expression profiling (GEP). With the aim of evaluating immune status in cancer patients, a gene panel consisting of 164 immune response-associated genes (56 antigen-presenting cell and T-cell-associated genes, 34 cytokine- and metabolism-associated genes, 47 TNF and TNF receptor superfamily genes, and 27 regulatory T-cell-associated genes) was established, and its expression and mutation status were investigated using 1,000 cancer patient-derived tumors. Regarding WES, sequencing and variant calling were performed using the Ion Proton system. The average number of single-nucleotide variants (SNVs) detected per sample was 183 ± 507, and the number of hypermutators with more than 500 total SNVs was 51 cases. Regarding GEP, seven immune response-associated genes (VTCN1, IL2RA, ULBP2, TREM1, MSR1, TNFSF9 and TNFRSF12A) were more than 2-fold overexpressed compared with normal tissues in more than 2 organs. Specifically, the positive rate of PD-L1 expression in all patients was 25.8%, and PD-L1 expression was significantly upregulated in hypermutators. The simultaneous analyses of WES and GEP based on immune response-associated genes are very intriguing tools to screen cancer patients suitable for immune checkpoint antibody therapy.

Integrated next-generation sequencing analysis of whole exome and 409 cancer-related genes

The use of next-generation sequencing (NGS) techniques to analyze the genomes of cancer cells has identified numerous genomic alterations, including single-base substitutions, small insertions and deletions, amplification, recombination, and epigenetic modifications. NGS contributes to the clinical management of patients as well as new discoveries that identify the mechanisms of tumorigenesis. Moreover, analysis of gene panels targeting actionable mutations enhances efforts to optimize the selection of chemotherapeutic regimens. However, whole genome sequencing takes several days and costs at least $10,000, depending on sequence coverage. Therefore, laboratories with relatively limited resources must employ a more economical approach. For this purpose, we conducted an integrated nucleotide sequence analysis of a panel of 409-cancer related genes (409-CRG) combined with whole exome sequencing (WES). Analysis of the 409-CRG panel detected low-frequency variants with high sensitivity, and WES identified moderate and high frequency somatic variants as well as germline variants.

Subcycle Optical Response Caused by a Terahertz Dressed State with Phase-Locked Wave Functions

The coherent interaction of light with matter imprints the phase information of the light field on the wave function of the photon-dressed electronic state. A driving electric field, together with a stable phase that is associated with the optical probe pulses, enables the role of the dressed state in the optical response to be investigated. We observed optical absorption strengths modulated on a subcycle time scale in a GaAs quantum well in the presence of a multicycle terahertz driving pulse using a near-infrared probe pulse. The measurements were in good agreement with the analytical formula that accounts for the optical susceptibilities caused by the dressed state of the excitons, which indicates that the output probe intensity was coherently reshaped by the excitonic sideband emissions.

Next generation sequencing approach for detecting 491 fusion genes from human cancer

Next-generation DNA sequencing (NGS) of the genomes of cancer cells is contributing to new discoveries that illuminate the mechanisms of tumorigenesis. To this end, the International Cancer Genome Consortium and The Cancer Genome Atlas are investigating novel alterations of genes that will define the pathways and mechanisms of the development and growth of cancers. These efforts contribute to the development of innovative pharmaceuticals as well as to the introduction of genome sequencing as a component of personalized medicine. In particular, chromosomal translocations that fuse coding sequences serve as important pharmaceutical targets and diagnostic markers given their association with tumorigenesis. Although increasing numbers of fusion genes are being discovered using NGS, the methodology used to identify such fusion genes is complicated, expensive, and requires relatively large samples. Here, to address these problems, we describe the design and development of a panel of 491 fusion genes that performed well in the analysis of cultured human cancer cell lines and 600 clinical tumor specimens.

Variants associated with autoimmune Type 1 diabetes in Japanese children: implications for age-specific effects of cis-regulatory haplotypes at 17q12-q21

AIMS

The aim of this study was to clarify the significance of previously reported susceptibility variants in the development of autoimmune Type 1 diabetes in non-white children. Tested variants included rs2290400, which has been linked to Type 1 diabetes only in one study on white people. Haplotypes at 17q12-q21 encompassing rs2290400 are known to determine the susceptibility of early-onset asthma by affecting the expression of flanking genes.

METHODS

We genotyped 63 variants in 428 Japanese people with childhood-onset autoimmune Type 1 diabetes and 457 individuals without diabetes. Possible association between variants and age at diabetes onset was examined using age-specific quantitative trait locus analysis and ordered-subset regression analysis.

RESULTS

Ten variants, including rs2290400 in GSDMB, were more frequent among the people with Type 1 diabetes than those without diabetes. Of these, rs689 in INS and rs231775 in CTLA4 yielded particularly high odds ratios of 5.58 (corrected P value 0.001; 95% CI 2.15-14.47) and 1.64 (corrected P value 5.3 × 10^-5 ; 95% CI 1.34-2.01), respectively. Age-specific effects on diabetes susceptibility were suggested for rs2290400; heterozygosity of the risk alleles was associated with relatively early onset of diabetes, and the allele was linked to the phenotype exclusively in the subgroup of age at onset ≤ 5.0 years.

CONCLUSIONS

The results indicate that rs2290400 in GSDMB and polymorphisms in INS and CTLA4 are associated with the risk of Type 1 diabetes in Japanese children. Importantly, cis-regulatory haplotypes at 17q12-q21 encompassing rs2290400 probably determine the risk of autoimmune Type 1 diabetes predominantly in early childhood.

Novel Tumor-specific Mutations in Receptor Tyrosine Kinase Subdomain IX Significantly Reduce Extracellular Signal-regulated Kinase Activity

BACKGROUND/AIM

The identification of additional therapeutic targets by clinical molecular profiling is necessary to expand the range of molecular-targeted cancer therapeutics. This study aimed to identify novel functional tumor-specific single nucleotide variants (SNVs) in the kinase domain of receptor tyrosine kinases (RTKs), from whole-exome sequencing (WES) data.

MATERIALS AND METHODS

SNVs were selected from WES data of multiple cancer types using both cancer-related databases and the index reflecting molecular evolution. Immunoblotting and luciferase assay were performed to assess the function of selected SNVs.

RESULTS

Among the seven selected SNVs, two, namely neurotrophic receptor tyrosine kinase 1 (NTRK1) V710A and fms related tyrosine kinase 3 (FLT3) K868N, detected in kinase subdomain IX, were investigated. These SNVs inhibited the autophosphorylation of the respective RTKs, thereby reducing the activity of extracellular signal-regulated kinases.

CONCLUSION

RTK subdomain IX is a promising target for the molecular design of kinase inhibitors.

Effective Treatment With Everolimus for Recurrent Granulomatous Interstitial Nephritis in a Renal Transplant Recipient: A Case Report

BACKGROUND

Granulomatous interstitial nephritis (GIN) is a rare renal disease, and its etiology remains unknown. We report recurrent GIN in renal allograft successfully treated with everolimus (EVR).

CASE REPORT

A 22-year-old man with GIN received a kidney from his mother. On follow-up 8 months later, his serum creatinine level was increased, from 1.3 mg/dL to 1.7 mg/dL, and he had microhematuria and proteinuria. A protocol graft biopsy at 1 year after transplantation showed epithelioid granuloma with multinucleated giant cells. He received steroid pulse therapy for recurrent GIN twice, but he developed allograft dysfunction, hematuria, and proteinuria. EVR was started in combination with maintenance immunosuppressants at 28 months after transplantation. Thereafter, the serum creatinine level decreased, from 2.1 mg/dL to 1.6 mg/dL, and microhematuria and proteinuria were stable despite reduction of steroid dose.

CONCLUSIONS

Maintenance immunosuppressive therapy combined with EVR may be effective for the recurrence of idiopathic GIN in renal allograft.

ProGRP is a possible tumor marker for patients with Ewing sarcoma

We analyzed serum ProGRP levels in patients with Ewing sarcoma, and found that 5 out of 9 patients had elevated levels; the values range equally with those of patients with limited disease of small-cell lung carcinoma. Serum ProGRP levels in patients with bone and soft tissue malignancies other than Ewing sarcoma are not elevated. Immunohistochemical studies demonstrated that ProGRP-like immunoreactivities were detected in Ewing sarcoma tissues obtained from 2 patients with elevated serum ProGRP levels, suggesting that ProGRP is a product of tumor cells of Ewing sarcoma. These results indicate that serum ProGRP could serve as a specific tumor marker for Ewing sarcoma. Since ProGRP is a major hormonal product of tumor cells of small-cell lung carcinoma, a typical neuroendocrine carcinoma, it is reasonable to postulate that the present study provides an evidence for Ewing sarcoma to possess neuroendocrine differentiation.