Exosomal microRNAs (miRNAs) have been attracting major interest as potential diagnostic biomarkers of cancer. The aim of this study was to characterize the miRNA profiles of serum exosomes and to ...identify those that are altered in colorectal cancer (CRC). To evaluate their use as diagnostic biomarkers, the relationship between specific exosomal miRNA levels and pathological changes of patients, including disease stage and tumor resection, was examined.
Microarray analyses of miRNAs in exosome-enriched fractions of serum samples from 88 primary CRC patients and 11 healthy controls were performed. The expression levels of miRNAs in the culture medium of five colon cancer cell lines were also compared with those in the culture medium of a normal colon-derived cell line. The expression profiles of miRNAs that were differentially expressed between CRC and control sample sets were verified using 29 paired samples from post-tumor resection patients. The sensitivities of selected miRNAs as biomarkers of CRC were evaluated and compared with those of known tumor markers (CA19-9 and CEA) using a receiver operating characteristic analysis. The expression levels of selected miRNAs were also validated by quantitative real-time RT-PCR analyses of an independent set of 13 CRC patients.
The serum exosomal levels of seven miRNAs (let-7a, miR-1229, miR-1246, miR-150, miR-21, miR-223, and miR-23a) were significantly higher in primary CRC patients, even those with early stage disease, than in healthy controls, and were significantly down-regulated after surgical resection of tumors. These miRNAs were also secreted at significantly higher levels by colon cancer cell lines than by a normal colon-derived cell line. The high sensitivities of the seven selected exosomal miRNAs were confirmed by a receiver operating characteristic analysis.
Exosomal miRNA signatures appear to mirror pathological changes of CRC patients and several miRNAs are promising biomarkers for non-invasive diagnosis of the disease.
Adipocytokines are adipocyte‐secreted hormones associated with some malignancies such as colorectal, breast, and prostate cancer. We hypothesized that changes in the levels of adipocytokines may ...indicate the carcinogenesis and progression of colorectal cancer and adenoma, and investigated the association of the blood levels of several adipocytokines through a case‐control study. Blood levels of adiponectin, leptin, resistin, visfatin, and C‐peptide at diagnosis were measured in 115 colorectal cancer patients and 115 age‐, sex‐, and body mass index‐matched controls. The same analysis was performed in 72 colorectal adenoma patients and 72 controls. Logistic regression models were used for estimating odds ratios and 95% confidence intervals, and one‐way anova was performed to determine the prevalence of each variable between two or more groups. Resistin and visfatin levels in cancer patients were significantly higher than those of controls on multivariate analysis (P = 0.03 and P < 0.01, respectively). Stage progression significantly correlated with resistin and visfatin levels (P < 0.01 for both). The adiponectin level in adenoma patients was significantly lower than that of controls on multivariate analysis (P = 0.04). Its level was inversely correlated with the number of adenoma (P = 0.02), but not correlated with the size of adenoma. Resistin and visfatin may be good biomarkers of colorectal malignant potential and stage progression. Adiponectin level may be a good biomarker of colorectal adenoma.
(Cancer Sci 2010; 101: 1286–1291)
Cholangiocarcinoma is an intractable cancer, with limited therapeutic options, in which the molecular mechanisms underlying tumor development remain poorly understood. Identification of a novel ...driver oncogene and applying it to targeted therapies for molecularly defined cancers might lead to improvements in the outcome of patients. We performed massively parallel whole transcriptome sequencing in eight specimens from cholangiocarcinoma patients without KRAS/BRAF/ROS1 alterations and identified two fusion kinase genes, FGFR2‐AHCYL1 and FGFR2‐BICC1. In reverse‐transcriptase polymerase chain reaction (RT‐PCR) screening, the FGFR2 fusion was detected in nine patients with cholangiocarcinoma (9/102), exclusively in the intrahepatic subtype (9/66, 13.6%), rarely in colorectal (1/149) and hepatocellular carcinoma (1/96), and none in gastric cancer (0/212). The rearrangements were mutually exclusive with KRAS/BRAF mutations. Expression of the fusion kinases in NIH3T3 cells activated MAPK and conferred anchorage‐independent growth and in vivo tumorigenesis of subcutaneous transplanted cells in immune‐compromised mice. This transforming ability was attributable to its kinase activity. Treatment with the fibroblast growth factor receptor (FGFR) kinase inhibitors BGJ398 and PD173074 effectively suppressed transformation. Conclusion: FGFR2 fusions occur in 13.6% of intrahepatic cholangiocarcinoma. The expression pattern of these fusions in association with sensitivity to FGFR inhibitors warrant a new molecular classification of cholangiocarcinoma and suggest a new therapeutic approach to the disease. (Hepatology 2014;59:1427‐1434)
Liquid biopsy of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) is gaining attention as a method for real‐time monitoring in cancer patients. Conventional methods based upon ...epithelial cell adhesion molecule (EpCAM) expression have a risk of missing the most aggressive CTC subpopulations due to epithelial‐mesenchymal transition and may, thus, underestimate the total number of actual CTC present in the bloodstream. Techniques utilizing a label‐free inertial microfluidics approach (LFIMA) enable efficient capture of CTC without the need for EpCAM expression. In this study, we optimized a method for analyzing genetic alterations using next‐generation sequencing (NGS) of extracted ctDNA and CTC enriched using an LFIMA as a first‐phase examination of 30 patients with head and neck cancer, esophageal cancer, gastric cancer and colorectal cancer (CRC). Seven patients with advanced CRC were enrolled in the second‐phase examination to monitor the emergence of alterations occurring during treatment with epidermal growth factor receptor (EGFR)‐specific antibodies. Using LFIMA, we effectively captured CTC (median number of CTC, 14.5 cells/mL) from several types of cancer and detected missense mutations via NGS of CTC and ctDNA. We also detected time‐dependent genetic alterations that appeared during anti–EGFR therapy in CTC and ctDNA from CRC patients. The results of NGS analyses indicated that alterations in the genomic profile revealed by the liquid biopsy could be expanded by using a combination of assays with CTC and ctDNA. The study was registered with the University Hospital Medical Information Network Clinical Trials Registry (ID: UMIN000014095).
In summary, we optimized the efficiency of a platform for capturing circulating tumor cells (CTC) using a label‐free inertial microfluidics approach and revealed the importance of both CTC and circulating tumor DNA (ctDNA) as diagnostic tools. In addition, our data suggest that both CTC and ctDNA can be used to closely monitor the emergence of molecular changes in patients with metastatic colorectal cancer.
Parkinson disease (PD) is the most common neurodegenerative movement disorder. An increase in the amount of α-synuclein protein could constitute a cause of PD. α-Synuclein is degraded at least partly ...by chaperone-mediated autophagy (CMA). The I93M mutation in ubiquitin C-terminal hydrolase L1 (UCH-L1) is associated with familial PD. However, the relationship between α-synuclein and UCH-L1 in the pathogenesis of PD has remained largely unclear. In this study, we found that UCH-L1 physically interacts with LAMP-2A, the lysosomal receptor for CMA, and Hsc70 and Hsp90, which can function as components of the CMA pathway. These interactions were abnormally enhanced by the I93M mutation and were independent of the monoubiquitin binding of UCH-L1. In a cell-free system, UCH-L1 directly interacted with the cytosolic region of LAMP-2A. Expression of I93M UCH-L1 in cells induced the CMA inhibition-associated increase in the amount of α-synuclein. Our findings may provide novel insights into the molecular links betweenα-synuclein and UCH-L1 and suggest that aberrant interaction of mutant UCH-L1 with CMA machinery, at least partly, underlies the pathogenesis of PD associated with I93M UCH-L1.
The recent discovery and characterization of an oncogenic ROS1 gene fusion in a subset of lung cancers has raised significant clinical interest because small molecule inhibitors may be effective to ...these tumors. As lung cancers with ROS1 rearrangements comprise only 1–3% of lung adenocarcinomas, patients with such tumors must be identified to gain optimal benefit from molecular therapy. Recently, immunohistochemical analyses using a novel anti-ROS1 rabbit monoclonal antibody (D4D6) have shown promise for accurate identification of ROS1-rearranged cancers. To validate this finding, we compared the immunostaining results of tissue microarrays (TMAs) containing 17 ROS1-rearranged and 253 ROS1-non-rearranged lung carcinomas. All 17 ROS1-rearranged cancers showed ROS1 immunoreactivity mostly in a diffuse and moderate-to-strong manner with an H-score range of 5–300 (median, 260). In contrast, 69% of ROS1-non-rearranged cancers lacked detectable immunoreactivity, whereas the remaining 31% showed reactivity mainly in a weak or focal manner. The H-score for the entire ROS1-non-rearranged group ranged from 0 to 240 (median, 0). The difference in H-score between the two cohorts was statistically significant, and the H-score cutoff (≥150) allowed optimal discrimination (94% sensitivity and 98% specificity). Similar but slightly less-specific performance was achieved using the extent of diffuse (≥75%) staining or ≥2+ staining intensity as cutoffs. CD74-ROS1 and EZR-ROS1 fusions were significantly associated with at least focal globular immunoreactivity and plasma membranous accentuation, respectively, and these patterns were specific to ROS1-rearranged cases. Although full-length ROS1 is expressed in some ROS1-non-rearranged cases, we showed that establishment of an optimal set of interpretative criteria makes ROS1 immunohistochemistry a valuable method to rapidly and accurately screen lung cancer patients for appropriate molecular therapy.
Activation of the EGFR, KRAS, and ALK oncogenes defines 3 different pathways of molecular pathogenesis in lung adenocarcinoma. However, many tumors lack activation of any pathway (triple-negative ...lung adenocarcinomas) posing a challenge for prognosis and treatment. Here, we report an extensive genome-wide expression profiling of 226 primary human stage I-II lung adenocarcinomas that elucidates molecular characteristics of tumors that harbor ALK mutations or that lack EGFR, KRAS, and ALK mutations, that is, triple-negative adenocarcinomas. One hundred and seventy-four genes were selected as being upregulated specifically in 79 lung adenocarcinomas without EGFR and KRAS mutations. Unsupervised clustering using a 174-gene signature, including ALK itself, classified these 2 groups of tumors into ALK-positive cases and 2 distinct groups of triple-negative cases (groups A and B). Notably, group A triple-negative cases had a worse prognosis for relapse and death, compared with cases with EGFR, KRAS, or ALK mutations or group B triple-negative cases. In ALK-positive tumors, 30 genes, including ALK and GRIN2A, were commonly overexpressed, whereas in group A triple-negative cases, 9 genes were commonly overexpressed, including a candidate diagnostic/therapeutic target DEPDC1, that were determined to be critical for predicting a worse prognosis. Our findings are important because they provide a molecular basis of ALK-positive lung adenocarcinomas and triple-negative lung adenocarcinomas and further stratify more or less aggressive subgroups of triple-negative lung ADC, possibly helping identify patients who may gain the most benefit from adjuvant chemotherapy after surgical resection.
The occurrence of inactivating mutations in SWI/SNF chromatin-remodeling genes in common cancers has attracted a great deal of interest. However, mechanistic strategies to target tumor cells carrying ...such mutations are yet to be developed. This study proposes a synthetic-lethality therapy for treating cancers deficient in the SWI/SNF catalytic (ATPase) subunit, BRG1/SMARCA4. The strategy relies upon inhibition of BRM/SMARCA2, another catalytic SWI/SNF subunit with a BRG1-related activity. Immunohistochemical analysis of a cohort of non-small-cell lung carcinomas (NSCLC) indicated that 15.5% (16 of 103) of the cohort, corresponding to preferentially undifferentiated tumors, was deficient in BRG1 expression. All BRG1-deficient cases were negative for alterations in known therapeutic target genes, for example, EGFR and DDR2 gene mutations, ALK gene fusions, or FGFR1 gene amplifications. RNA interference (RNAi)-mediated silencing of BRM suppressed the growth of BRG1-deficient cancer cells relative to BRG1-proficient cancer cells, inducing senescence via activation of p21/CDKN1A. This growth suppression was reversed by transduction of wild-type but not ATPase-deficient BRG1. In support of these in vitro results, a conditional RNAi study conducted in vivo revealed that BRM depletion suppressed the growth of BRG1-deficient tumor xenografts. Our results offer a rationale to develop BRM-ATPase inhibitors as a strategy to treat BRG1/SMARCA4-deficient cancers, including NSCLCs that lack mutations in presently known therapeutic target genes.
Purpose Adipocytokines are adipocyte-secreted hormones associated with some malignancies. We investigated the association of adipocytokines with gastric cancer. Methods The levels of body mass index ...(BMI) and adiponectin, leptin, resistin, visfatin, and C-peptide in blood at diagnosis were measured in 156 gastric cancer patients and 156 age- and sex-matched controls. Logistic regression models were used to estimate odds ratio, and one-way analysis of variance was performed to examine the prevalence of each variable between 2 or more groups. Results Adiponectin, C-peptide and BMI levels were significantly lower, and resistin and visfatin levels were significantly higher in the patients on multivariate analysis (P = 0.0004, 0.0006, 0.0051, 0.0006 and 0.0013, respectively). In the controls, the inverse correlation between BMI and adiponectin was comparatively strong, but was weak in the patients. The correlation between BMI and leptin was strong in both the controls and the patients. The correlation between BMI and resistin or visfatin was not clear in either the patients or the controls. The correlation between BMI and C-peptide was not clear in the controls, but might be weak in the patients. Leptin, C-peptide and BMI levels gradually decreased with stage progression, and resistin and visfatin levels gradually increased with stage progression (P < 0.0001 for all). Comparison between 38 patients with Stage I gastric cancer and the controls showed that adiponectin level tended to decrease in the patients (P = 0.0582), and BMI level was not different between two groups (P = 0.2480). Conclusions Resistin and visfatin may be good biomarkers of gastric cancer.
Ewing sarcoma is a high-grade round cell sarcoma that affects bones and soft tissues in children and young adults. Its diagnosis can be challenging, and the differential diagnoses include a wide ...variety of small round cell tumors. CD99 and FLI-1 are the currently accepted immunohistochemical markers for Ewing sarcoma, but their accuracy has been controversial. NKX2.2 is a homeodomain-containing transcription factor that plays a critical role in neuroendocrine/glial differentiation. The NKX2.2 gene was recently identified as a target of EWS-FLI-1, the fusion protein specific to Ewing sarcoma, and was shown to be differentially upregulated in Ewing sarcoma on the basis of array-based gene expression analysis. However, the immunohistochemical diagnostic potential of this marker has not been tested. We immunostained representative sections of 30 genetically confirmed Ewing sarcomas and 130 non-Ewing small round cell tumors by using an antibody to NKX2.2. Nuclear staining in at least 5% of the cells was deemed positive. Twenty-eight (93%) of the 30 Ewing sarcomas were positive for NKX2.2. The staining was diffuse (>50%) in all the positive cases and was moderate or strong in intensity for most cases (25 of 28). NKX2.2 was also positive in 14 non-Ewing tumors, including all the olfactory neuroblastomas and a minor subset of small cell carcinomas, synovial sarcomas, mesenchymal chondrosarcomas, and malignant melanomas. All the other non-Ewing tumors tested were negative for this marker. NKX2.2 is a valuable marker for Ewing sarcoma, with a sensitivity of 93% and a specificity of 89%, and aids in the differential diagnosis of small round cell tumors.
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