Copy number gain of ACTN4 is associated with poor prognosis in patients with upper urinary tract urothelial carcinoma.

α-Actinin4 (ACTN4), an isoform of non-muscular α-actinin, is involved in enhancing cell motility and promoting cancer infiltration and metastasis in various cancers. However, information remains limited regarding the pathological significance of ACTN4 expression in upper urinary tract urothelial carcinomas (UUTUCs). We obtained tumor samples from 168 consecutive patients with newly diagnosed UUTUCs (92 with renal pelvic cancers and 76 with ureteral cancers), who were treated with nephroureterectomy or partial ureterectomy, and analyzed the expression of the ACTN4 protein and the amplification of ACTN4 using immunohistochemistry and fluorescence in situ hybridization (FISH), respectively. The median follow-up duration was 65 months. Among 168 cases, 49 (29%) showed ACTN4 protein overexpression and 25 (15%) showed copy number gain (≥4 copies per cell) of ACTN4. The copy number gain of ACTN4 detected using FISH significantly correlated with ACTN4 protein overexpression and several adverse clinicopathological factors, including higher pathological T stage, lymphovascular invasion, lymph node metastasis, positive surgical margin, concomitant subtype histology, and non-papillary gross finding. Cox univariate regression analyses revealed that both copy number gain of ACTN4 and ACTN4 protein overexpression were significant risk factors for extraurothelial recurrence and death (each p < 0.0001), but multivariate analysis revealed that only copy number gain of ACTN4 was an independent risk factor for extraurothelial recurrence and death (p = 0.038 and 0.027, hazard ratio = 2.16 and 2.17, respectively). This is the first study demonstrating the aberrant expression status of ACTN4 in UUTUC and indicating its putative usefulness as a prognostic indicator in patients with UUTUC.

Apolipoprotein A2 isoforms associated with exocrine pancreatic insufficiency in early chronic pancreatitis.

BACKGROUND AND AIM: Apolipoprotein A2 (apoA2) isoforms have been reported to undergo the aberrant processing in pancreatic cancer and pancreatic risk populations compared with that in healthy subjects. This study aimed to clarify whether apoA2 isoforms were as useful as N-benzoyl-p-aminobenzoic acid (BT-PABA) test for exocrine pancreatic dysfunction markers in patients with early chronic pancreatitis (ECP). METHODS: Fifty consecutive patients with functional dyspepsia with pancreatic enzyme abnormalities (FD-P) (n = 18), with ECP (n = 20), and asymptomatic patients with pancreatic enzyme abnormalities (AP-P) (n = 12) based on the Rome IV classification and the Japan Pancreatic Association were enrolled in this study. The enrolled patients were evaluated using endoscopic ultrasonography and endoscopic ultrasonography elastography. Five pancreatic enzymes were estimated. Pancreatic exocrine function was analyzed using the BT-PABA test. Lighter and heavier apoA2 isoforms, AT and ATQ levels were measured by enzyme-linked immunosorbent assay methods. RESULTS: There were no significant differences in clinical characteristics such as age, gender, body mass index, alcohol consumption and smoking among patients with AP-P, FD-P, and ECP. The BT-PABA test and lighter apoA2 isoform, AT level in the enrolled patients had a significant correlation (P < 0.01). The BT-PABA test in patients with ECP was significantly lower (P = 0.04) than that in AP-P. ApoA2-AT level in patients with ECP was lower than that in AP-P, albeit, insignificantly. Interestingly, apo A2-AT level was significantly (P = 0.041) associated with exocrine pancreatic insufficiency by multiple logistic regression analysis. CONCLUSIONS: ApoA2-AT level is a useful tool to evaluate exocrine pancreatic insufficiency in the early stage of chronic pancreatitis.

Noninvasive risk stratification of intraductal papillary mucinous neoplasia with malignant potential by serum apolipoprotein-A2-isoforms.

Intraductal papillary mucinous neoplasms (IPMNs) are premalignant lesions of pancreatic cancer. An accurate serum biomarker, which allows earlier identification of asymptomatic individuals with high-risk for developing cancer, is of urgent need. Apolipoprotein A2-isoforms (apoA2-i) have previously been identified as biomarkers in pancreatic cancer. This study investigates a potential clinical application of the serum apoA2-i for risk stratification of IPMN and associated cancer. The concentrations of apoA2-i were retrospectively determined in 523 patient sera specimen, composed of 305 IPMNs with preinvasive lesions with different grades of dysplasia and invasive cancer, 140 pancreatic ductal adenocarcinoma, 78 with other cystic lesions and healthy controls cohorts, using an apoA2-i enzyme-linked immunosorbent assay kit. The diagnostic performance of serum apoA2-i was assessed and compared to routine clinical marker CA 19-9. ApoA2-i levels were significantly reduced in all IPMN samples regardless of stage compared to healthy controls. Receiver operating characteristic curve analysis of IPMNs with high-grade dysplasia and IPMN with associated carcinoma revealed the area under curve (AUC) of 0.91 and >0.94, respectively. The respective sensitivities were 70% and 83% with a specificity of 95%, and significantly higher than the gold standard biomarker CA 19-9. AUC values of apoA2-i for detecting IPMN-associated carcinoma of colloid and ductal subtypes were 0.990 and 0.885, respectively. ApoA2-i has the potential to early detect the risk of malignancy of patients with IPMN. The serological apoA2-i test in combination with imaging modalities could help improve the diagnosis of IPMN malignancy. Further validation in larger and independent international cohort studies is needed.

Alpha-actinin-4 (ACTN4) gene amplification is a predictive biomarker for adjuvant chemotherapy with tegafur/uracil in stage I lung adenocarcinomas.

Although adjuvant tegafur/uracil (UFT) is recommended for patients with completely resected stage I non-small-cell lung cancer (NSCLC) in Japan, only one-third of cases has received adjuvant chemotherapy (ADJ) according to real-world data. Therefore, robust predictive biomarkers for selecting ADJ or observation (OBS) without ADJ are needed. Patients who underwent complete resection of stage I lung adenocarcinoma with or without adjuvant UFT were enrolled. The status of ACTN4 gene amplification was analyzed by FISH. Statistical analyses to determine whether the status of ACTN4 gene amplification affected recurrence-free survival (RFS) were carried out. Formalin-fixed, paraffin-embedded samples from 1136 lung adenocarcinomas were submitted for analysis of ACTN4 gene amplification. Ninety-nine (8.9%) of 1114 cases were positive for ACTN4 gene amplification. In the subgroup analysis of patients aged 65 years or older, the ADJ group had better RFS than the OBS group in the ACTN4-positive cohort (hazard ratio [HR], 0.084, 95% confidence interval [CI], 0.009-0.806; P = .032). The difference in RFS between the ADJ group and the OBS group was not significant in ACTN4-negative cases (all ages: HR, 1.214; 95% CI, 0.848-1.738; P = .289). Analyses of ACTN4 gene amplification contributed to the decision regarding postoperative ADJ for stage I lung adenocarcinomas, preventing recurrence, improving the quality of medical care, preventing the unnecessary side-effects of ADJ, and saving medical costs.

Prognostic impact of ACTN4 gene copy number alteration in hormone receptor-positive, HER2-negative, node-negative invasive breast carcinoma.

BACKGROUND: Most patients with hormone receptor (HR)-positive, human epidermal growth factor receptor type 2 (HER2)-negative breast cancer can be cured by surgery and endocrine therapy, but a significant proportion suffer recurrences. Actinin-4 is associated with cancer invasion and metastasis, and its genetic alteration may be used for breast cancer prognostication. METHODS: The copy number of the actinin-4 (ACTN4) gene was determined by fluorescence in situ hybridisation (FISH) in two independent cohorts totalling 597 patients (336 from Japan and 261 from the USA) with HR-positive, HER2-negative, node-negative breast cancer. RESULTS: In the Japanese cohort, multivariate analysis revealed that a copy number increase (CNI) of ACTN4 was an independent factor associated with high risks of recurrence (P = 0.01; hazard ratio (HR), 2.95) and breast cancer death (P = 0.014; HR, 4.27). The prognostic significance of ACTN4 CNI was validated in the US cohort, where it was the sole prognostic factor significantly associated with high risks of recurrence (P = 0.04; HR, 2.73) and death (P = 0.016; HR, 4.01). CONCLUSIONS: Copy number analysis of a single gene, ACTN4, can identify early-stage luminal breast cancer patients with a distinct outcome. Such high-risk patients may benefit from adjuvant chemotherapy.

CA19-9 and apolipoprotein-A2 isoforms as detection markers for pancreatic cancer: a prospective evaluation.

Recently, we identified unique processing patterns of apolipoprotein A2 (ApoA2) in patients with pancreatic cancer. Our study provides a first prospective evaluation of an ApoA2 isoform ("ApoA2-ATQ/AT"), alone and in combination with carbohydrate antigen 19-9 (CA19-9), as an early detection biomarker for pancreatic cancer. We performed ELISA measurements of CA19-9 and ApoA2-ATQ/AT in 156 patients with pancreatic cancer and 217 matched controls within the European EPIC cohort, using plasma samples collected up to 60 months prior to diagnosis. The detection discrimination statistics were calculated for risk scores by strata of lag-time. For CA19-9, in univariate marker analyses, C-statistics to distinguish future pancreatic cancer patients from cancer-free individuals were 0.80 for plasma taken ≤6 months before diagnosis, and 0.71 for >6-18 months; for ApoA2-ATQ/AT, C-statistics were 0.62, and 0.65, respectively. Joint models based on ApoA2-ATQ/AT plus CA19-9 significantly improved discrimination within >6-18 months (C = 0.74 vs. 0.71 for CA19-9 alone, p = 0.022) and ≤ 18 months (C = 0.75 vs. 0.74, p = 0.022). At 98% specificity, and for lag times of ≤6, >6-18 or ≤ 18 months, sensitivities were 57%, 36% and 43% for CA19-9 combined with ApoA2-ATQ/AT, respectively, vs. 50%, 29% and 36% for CA19-9 alone. Compared to CA19-9 alone, the combination of CA19-9 and ApoA2-ATQ/AT may improve detection of pancreatic cancer up to 18 months prior to diagnosis under usual care, and may provide a useful first measure for pancreatic cancer detection prior to imaging.

Live single cell mass spectrometry reveals cancer-specific metabolic profiles of circulating tumor cells.

Recently, there has been increased attention on the analysis of circulating tumor cells (CTCs), also known as liquid biopsy, owing to its potential benefits in cancer diagnosis and treatment. Circulating tumor cells are released from primary tumor lesions into the blood stream and eventually metastasize to distant body organs. However, a major hurdle with CTC analysis is their natural scarcity. Existing methods lack sensitivity, specificity, or reproducibility required in CTC characterization and detection. Here, we report untargeted molecular profiling of single CTCs obtained from gastric cancer and colorectal cancer patients, using live single cell mass spectrometry integrated with microfluidics-based cell enrichment techniques. Using this approach, we showed the difference in the metabolomic profile between CTCs originating from different cancer groups. Moreover, potential biomarkers were putatively annotated to be specific to each cancer type.

Monitoring of cancer patients via next-generation sequencing of patient-derived circulating tumor cells and tumor DNA.

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).

Leucine-Rich Alpha-2-Glycoprotein 1 in Serum Is a Possible Biomarker to Predict Response to Preoperative Chemoradiotherapy for Esophageal Cancer.

The purpose of the present study was to identify a biomarker that can predict the response to preoperative chemoradiotherapy (PCRT) in esophageal cancer patients. Twenty-five serum samples collected from patents with esophageal cancer before PCRT (responder = 13, non-responder = 12) were analyzed by quantitative proteomics, and 248 proteins were identified. Among them, the serum levels of leucine-rich alpha-2-glycoprotein 1 (LRG1) were significantly different (p < 0.01) and well discriminated (area under the curve (AUC) of the receiver operating characteristic (ROC) curve >0.8) between responder and non-responder groups. The combination of LRG1 with C-reactive protein (CRP) and soluble interleukin-6 receptor (sIL-6R), which were previously reported as biomarkers predicting PCRT response, further improved the predictive performance, providing an AUC of greater than 0.9. The present results suggest that LRG1 and its combination with CRP and sIL-6R are promising biomarker candidates to predict response to PCRT in esophageal cancer patients.

Serum apolipoprotein A2 isoforms in autoimmune pancreatitis.

Recently, apolipoprotein A2 (apoA2) isoforms have been reported as candidate serum/plasma biomarkers of pancreatic cancer. However, the distribution of apoA2 isoforms in patients with autoimmune pancreatitis (AIP) has not been investigated yet. In this study, we evaluated the distribution of serum apoA2 isoforms; i.e., homodimer apoA2-ATQ/ATQ, heterodimer apoA2-ATQ/AT, and homodimer apoA2-AT/AT, in AIP patients and healthy volunteers (HV) using enzyme-linked immunosorbent assays, and the clinical characteristics and serum levels of each apoA2 isoform in 32 AIP patients and 38 HV were investigated. The calculated apoA2-ATQ/AT levels of the AIP patients were significantly lower than those of the HV, which agreed with results obtained for patients with pancreatic cancer. Interestingly, most of the AIP patients exhibited high levels of apoA2-ATQ along with low levels of apoA2-AT, indicating that the processing of the C-terminal regions of apoA2 dimer was inhibited in the AIP patients. This specific distribution of serum apoA2 isoforms might provide important information about the disease states of AIP patients and aid the differential diagnosis of AIP versus pancreatic cancer.

Measurement of copy number of ACTN4 to optimize the therapeutic strategy for locally advanced pancreatic cancer.

The standard therapeutic strategy recommended for locally advanced pancreatic cancer (LAPC) is typically chemotherapy or chemoradiotherapy (CRT). Although the clinical benefit of chemotherapy alone versus CRT for LAPC has been compared in a number of clinical trials, the optimal therapy for LAPC remains unclear. Moreover, the clinical benefit derived from treatment in each clinical trial is a matter of controversy, and the superiority of one treatment over another has yet to be definitively demonstrated. The poor outcomes seen among patients with LAPC owe largely to the emergence of metastatic disease; therefore, accurately evaluating occult distant metastasis before choosing a therapeutic strategy could be expected to help stratify patients with LAPC into the most appropriate treatment regimen, namely local control or systemic therapy. In 1998, we identified the actinin-4 gene (ACTN4) as an actin-binding protein and showed its molecular mechanisms had clinical implications for cancer metastasis. We also identified ACTN4 gene amplification in pancreatic, ovarian, and salivary gland cancer, and demonstrated its utility as a strong prognostic biomarker for stage I lung adenocarcinoma in patients who had never received chemotherapy. Moreover, we recently reported that ACTN4 gene amplification could be a useful biomarker for predicting the efficacy of CRT for LAPC. In the present review, we summarize current knowledge regarding therapeutic strategies for LAPC and discuss the potential development of personalized medicine using ACTN4 measurement for patients with LAPC.

Alternative mammalian target of rapamycin (mTOR) signal activation in sorafenib-resistant hepatocellular carcinoma cells revealed by array-based pathway profiling.

Sorafenib is a multi-kinase inhibitor that has been proven effective for the treatment of unresectable hepatocellular carcinoma (HCC). However, its precise mechanisms of action and resistance have not been well established. We have developed high-density fluorescence reverse-phase protein arrays and used them to determine the status of 180 phosphorylation sites of signaling molecules in the 120 pathways registered in the NCI-Nature curated database in 23 HCC cell lines. Among the 180 signaling nodes, we found that the level of ribosomal protein S6 phosphorylated at serine residue 235/236 (p-RPS6 S235/236) was most significantly correlated with the resistance of HCC cells to sorafenib. The high expression of p-RPS6 S235/236 was confirmed immunohistochemically in biopsy samples obtained from HCC patients who responded poorly to sorafenib. Sorafenib-resistant HCC cells showed constitutive activation of the mammalian target of rapamycin (mTOR) pathway, but whole-exon sequencing of kinase genes revealed no evident alteration in the pathway. p-RPS6 S235/236 is a potential biomarker that predicts unresponsiveness of HCC to sorafenib. The use of mTOR inhibitors may be considered for the treatment of such tumors.

Junctional Rab13-binding protein (JRAB) regulates cell spreading via filamins.

We previously showed that Rab13 and its effector protein, junctional Rab13-binding protein (JRAB)/molecules interacting with CasL-like 2 (MICAL-L2), regulate junctional development by modulating cell adhesion molecule transport and actin cytoskeletal reorganization in epithelial cells. Here, we investigated how JRAB regulates reorganization of the actin cytoskeleton in NIH3T3 fibroblasts, in an attempt to obtain novel insights into the mechanism of JRAB action. To this end, we expressed mutant proteins that adopt a constitutively open or closed state and then examined effect on cellular morphology of the resulting actin cytoskeletal reorganization. Expression of the JRABΔCT mutant (constitutively 'closed' state) induced stress fibers, whereas expression of the JRABΔCC mutant (constitutively 'open' state) caused cell spreading with membrane ruffles. Next, we identified the proteins involved in JRAB-induced rearrangement of actin cytoskeleton leading to morphological changes. In NIH3T3 cells expressing HA-JRABΔCC, filamin, an actin cross-linking protein, coimmunoprecipitated with HA-JRABΔCC. Expression of ASB2 induced degradation of all three filamin isoforms and inhibited the JRABΔCC-induced cell spreading. Consistent with our previous results, actinin-1/-4 were also immunoprecipitated with HA-JRABΔCC. However, actinin-1/-4 have no effect on the cell spreading regulated by JRABΔCC. These data suggest that JRAB contributes to the rearrangement of the actin cytoskeleton during cell spreading via filamins.

MicroRNA expression and functional profiles of osteosarcoma.

OBJECTIVE: Osteosarcoma (OS) is the most frequent primary malignant bone tumor in children and young adults. Although the introduction of combined neoadjuvant chemotherapy has significantly prolonged survival, the outcome for OS patients showing a poor response to chemotherapy is still unfavorable. In order to develop new therapeutic approaches, elucidation of the entire molecular pathway regulating OS cell proliferation would be desirable. METHODS: MicroRNA (miRNA) are highly conserved noncoding RNA that play important roles in the development and progression of various other cancers. Using miRNA microarrays capable of detecting a known number of 933 miRNA, 108 miRNA were found to be commonly expressed in 24 samples of OS tissue and subjected to a cell proliferation assay. RESULTS: We found that inhibition of 5 let-7 family miRNA (hsa-let-7a, b, f, g and i) significantly suppressed the proliferation of OS cells. Using a quantitative shotgun proteomics approach, we also found that the let-7 family miRNA regulated the expression of vimentin and serpin H1 proteins. CONCLUSIONS: Our present results indicate the involvement of let-7 family miRNA in regulation of the cell proliferation as well as epithelial-mesenchymal transition of OS. Thus, let-7 family miRNA may potentially provide novel targets for the development of therapeutic strategies against OS.

Phosphoproteomic Analysis Identified Mutual Phosphorylation of FAK and Src as a Mechanism of Osimertinib Resistance in EGFR-Mutant Lung Cancer.

Introduction: Osimertinib is a standard treatment for patients with EGFR-mutant NSCLC. Although some osimertinib resistance mechanisms have been identified, nearly 50% of the mechanisms remain to be elucidated. This study was aimed at identifying non-genetic mechanisms underlying osimertinib resistance. Methods: We established two osimertinib-resistant cell lines from EGFR mutation-positive PC-9 and HCC827 NSCLC cell lines (PC-9OR and HCC827OR, respectively) using a stepwise method. We compared the phosphoproteomic profiles of the osimertinib-resistant and parental cells using mass spectrometry. Upstream kinases were identified using the application Kinase Enrichment Analysis version 3. Results: Phosphoproteomic analysis revealed 80 phosphorylation sites that were mutually up-regulated in PC-9OR and HCC827OR cells. The Kinase Enrichment Analysis version 3 analysis identified focal adhesion kinase (FAK) and proto-oncogene tyrosine-protein kinase Src (Src) as upstream kinases of these up-regulated phosphoproteins. The small-interfering RNA-mediated knockdown of FAK reduced Src phosphorylation and that of Src reduced FAK phosphorylation in both cell lines. Furthermore, FAK- or Src-specific small-interfering RNA treatments restored EGFR phosphorylation in PC-9OR and HCC827OR cells. The combination of FAK and Src inhibitors inhibited PC-9OR and HCC827OR cell proliferation in vitro and suppressed tumor growth in a xenograft mouse model. Immunohistochemistry of tumors from patients with EGFR-mutant NSCLC suggested that phosphorylated FAK and Src are involved in initial and acquired resistance to osimertinib. Conclusions: Phosphoproteomic analysis may help elucidate the mechanisms of resistance to molecular-targeted therapies in lung cancer. Mutual phosphorylation of FAK and Src is involved in osimertinib resistance. Thus, FAK and Src inhibition may be novel treatment strategies for osimertinib-resistant NSCLC.

Thioester-Based Coupled Fluorogenic Assays in Microdevice for the Detection of Single-Molecule Enzyme Activities of Esterases with Specified Substrate Recognition.

Single-molecule enzyme activity assay is a platform that enables the analysis of enzyme activities at single proteoform level. The limitation of the targetable enzymes is the major drawback of the assay, but the general assay platform is reported to study single-molecule enzyme activities of esterases based on the coupled assay using thioesters as substrate analogues. The coupled assay is realized by developing highly water-soluble thiol-reacting probes based on phosphonate-substituted boron dipyrromethene (BODIPY). The system enables the detection of cholinesterase activities in blood samples at single-molecule level, and it is shown that the dissecting alterations of single-molecule esterase activities can serve as an informative platform for activity-based diagnosis.

Identification of activity-based biomarkers for early-stage pancreatic tumors in blood using single-molecule enzyme activity screening.

Single-molecule enzyme activity-based enzyme profiling (SEAP) is a methodology to globally analyze protein functions in living samples at the single-molecule level. It has been previously applied to detect functional alterations in phosphatases and glycosidases. Here, we expand the potential for activity-based biomarker discovery by developing a semi-automated synthesis platform for fluorogenic probes that can detect various peptidases and protease activities at the single-molecule level. The peptidase/protease probes were prepared on the basis of a 7-amino-4-methylcoumarin fluorophore. The introduction of a phosphonic acid to the core scaffold made the probe suitable for use in a microdevice-based assay, while phosphonic acid served as the handle for the affinity separation of the probe using Phos-tag. Using this semi-automated scheme, 48 fluorogenic probes for the single-molecule peptidase/protease activity analysis were prepared. Activity-based screening using blood samples revealed altered single-molecule activity profiles of CD13 and DPP4 in blood samples of patients with early-stage pancreatic tumors. The study shows the power of single-molecule enzyme activity screening to discover biomarkers on the basis of the functional alterations of proteins.

Clinical development of a blood biomarker using apolipoprotein-A2 isoforms for early detection of pancreatic cancer.

BACKGROUND: We have previously reported apolipoprotein A2-isoforms (apoA2-is) as candidate plasma biomarkers for early-stage pancreatic cancer. The aim of this study was the clinical development of apoA2-is. METHODS: We established a new enzyme-linked immunosorbent sandwich assay for apoA2-is under the Japanese medical device Quality Management System requirements and performed in vitro diagnostic tests with prespecified end points using 2732 plasma samples. The clinical equivalence and significance of apoA2-is were compared with CA19-9. RESULTS: The point estimate of the area under the curve to distinguish between pancreatic cancer (n = 106) and healthy controls (n = 106) was higher for apoA2-ATQ/AT [0.879, 95% confidence interval (CI): 0.832-0.925] than for CA19-9 (0.849, 95% CI 0.793-0.905) and achieved the primary end point. The cutoff apoA2-ATQ/AT of 59.5 µg/mL was defined based on a specificity of 95% in 2000 healthy samples, and the reliability of specificities was confirmed in two independent healthy cohorts as 95.3% (n = 106, 95% CI 89.4-98.0%) and 95.8% (n = 400, 95% CI 93.3-97.3%). The sensitivities of apoA2-ATQ/AT for detecting both stage I (47.4%) and I/II (50%) pancreatic cancers were higher than those of CA19-9 (36.8% and 46.7%, respectively). The combination of apoA2-ATQ/AT (cutoff, 59.5 µg/mL) and CA19-9 (37 U/mL) increased the sensitivity for pancreatic cancer to 87.7% compared with 69.8% for CA19-9 alone. The clinical performance of apoA2-is was blindly confirmed by the National Cancer Institute Early Detection Research Network. CONCLUSIONS: The clinical performance of ApoA2-ATQ/AT as a blood biomarker is equivalent to or better than that of CA19-9.

Rab13 small G protein and junctional Rab13-binding protein (JRAB) orchestrate actin cytoskeletal organization during epithelial junctional development.

During epithelial junctional development, both vesicle transport and reorganization of the actin cytoskeleton must be spatiotemporally regulated. Coordination of these cellular functions is especially important, but the precise mechanism remains elusive. Previously, we identified junctional Rab13-binding protein (JRAB)/molecules interacting with CasL-like 2 (MICAL-L2) as an effector of the Rab13 small G protein, and we found that the Rab13-JRAB system may be involved in the formation of cell-cell adhesions via transport of adhesion molecules. Here, we showed that JRAB interacts with two actin-binding proteins, actinin-1 and -4, and filamentous actin via different domains and regulates actin cross-linking and stabilization through these interactions. During epithelial junctional development, JRAB is prominently enriched in the actin bundle at the free border; subsequently, JRAB undergoes a Rab13-dependent conformational change that is required for maturation of cell-cell adhesion sites. These results suggest that Rab13 and JRAB regulate reorganization of the actin cytoskeleton throughout epithelial junctional development from establishment to maturation of cell-cell adhesion.