Exploratory Biomarker Analysis Using Plasma Angiogenesis-Related Factors and Cell-Free DNA in the TRUSTY Study: A Randomized, Phase II/III Study of Trifluridine/Tipiracil Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer.

BACKGROUND: The TRUSTY study evaluated the efficacy of second-line trifluridine/tipiracil (FTD/TPI) plus bevacizumab in metastatic colorectal cancer (mCRC). OBJECTIVE: This exploratory biomarker analysis of TRUSTY investigated the relationship between baseline plasma concentrations of angiogenesis-related factors and cell-free DNA (cfDNA), and the efficacy of FTD/TPI plus bevacizumab in patients with mCRC. PATIENTS AND METHODS: The disease control rate (DCR) and progression-free survival (PFS) were compared between baseline plasma samples of patients with high and low plasma concentrations (based on the median value) of angiogenesis-related factors. Correlations between cfDNA concentrations and PFS were assessed. RESULTS: Baseline characteristics (n = 65) were as follows: male/female, 35/30; median age, 64 (range 25-84) years; and RAS status wild-type/mutant, 29/36. Patients in the hepatocyte growth factor (HGF)-low and interleukin (IL)-8-low groups had a significantly higher DCR (risk ratio [95% confidence intervals {CIs}]) than patients in the HGF-high (1.83 [1.12-2.98]) and IL-8-high (1.70 [1.02-2.82]) groups. PFS (hazard ratio {HR} [95% CI]) was significantly longer in patients in the HGF-low (0.33 [0.14-0.79]), IL-8-low (0.31 [0.14-0.70]), IL-6-low (0.19 [0.07-0.50]), osteopontin-low (0.39 [0.17-0.88]), thrombospondin-2-low (0.42 [0.18-0.98]), and tissue inhibitor of metalloproteinase-1-low (0.26 [0.10-0.67]) groups versus those having corresponding high plasma concentrations of these angiogenesis-related factors. No correlation was observed between cfDNA concentration and PFS. CONCLUSION: Low baseline plasma concentrations of HGF and IL-8 may predict better DCR and PFS in patients with mCRC receiving FTD/TPI plus bevacizumab, however further studies are warranted. CLINICAL TRIAL REGISTRATION NUMBER: jRCTs031180122.

Trifluridine/tipiracil+bevacizumab (BEV) vs. fluoropyrimidine-irinotecan+BEV as second-line therapy for metastatic colorectal cancer: a randomised noninferiority trial.

BACKGROUND: This open-label, multicentre, phase II/III trial assessed the noninferiority of trifluridine/tipiracil (FTD/TPI) plus bevacizumab vs. fluoropyrimidine and irinotecan plus bevacizumab (control) as second-line treatment for metastatic colorectal cancer (mCRC). METHODS: Patients were randomised (1:1) to receive FTD/TPI (35 mg/m2 twice daily, days 1-5 and days 8-12, 28-day cycle) plus bevacizumab (5 mg/kg, days 1 and 15) or control. The primary endpoint was overall survival (OS). The noninferiority margin of the hazard ratio (HR) was set to 1.33. RESULTS: Overall, 397 patients were enrolled. Baseline characteristics were similar between the groups. Median OS was 14.8 vs. 18.1 months (FTD/TPI plus bevacizumab vs. control; HR 1.38; 95% confidence interval [CI] 0.99-1.93; Pnoninferiority = 0.5920). In patients with a baseline sum of the diameter of target lesions of <60 mm (n = 216, post hoc analyses), the adjusted median OS was similar between groups (FTD/TPI plus bevacizumab vs. control, 21.4 vs. 20.7 months; HR 0.92; 95% CI 0.55-1.55). Grade ≥3 adverse events (FTD/TPI plus bevacizumab vs. control) included neutropenia (65.8% vs. 41.6%) and diarrhoea (1.5% vs. 7.1%). CONCLUSIONS: FTD/TPI plus bevacizumab did not demonstrate noninferiority to fluoropyrimidine and irinotecan plus bevacizumab as second-line treatment for mCRC. CLINICAL TRIAL REGISTRATION: JapicCTI-173618, jRCTs031180122.

Involvement of clusterin expression in the refractory response of pancreatic cancer cells to a MEK inhibitor.

Constitutive activation of the mitogen-activated protein kinase (MAPK) signaling pathway is essential for tumorigenesis of pancreatic ductal adenocarcinoma (PDAC). To date, however, almost all clinical trials of inhibitor targeting this pathway have failed to improve the outcome of patients with PDAC. We found that implanted MIA Paca2, a human PDAC cell line sensitive to a MAPK inhibitor, PD0325901, became refractory within a week after treatment. By comparing the expression profiles of MIA Paca2 before and after acquisition of the refractoriness to PD0325901, we identified clusterin (CLU) as a candidate gene involved. CLU was shown to be induced immediately after treatment with PD0325901 or expressed primarily in more than half of PDAC cell lines, enhancing cell viability by escaping from apoptosis. A combination of PD0325901 and CLU downregulation was found to synergistically or additively reduce the proliferation of PDAC cells. In surgically resected PDAC tissues, overexpression of CLU in cancer cells was observed immunohistochemically in approximately half of the cases studied. Collectively, our findings highlight the mechanisms responsible for the rapid refractory response to MEK inhibitor in PDAC cells, suggesting a novel therapeutic strategy that could be applicable to patients with PDAC using inhibitor targeting the MAPK signaling pathway and CLU.

A multicentre retrospective study comparing site-specific treatment with empiric treatment for unfavourable subset of cancer of unknown primary site.

BACKGROUND: Patients with cancer of unknown primary site are divided into two distinct groups, favourable and unfavourable subsets. For the unfavourable subset, empiric treatment or site-specific treatment is recommended, but limited knowledge exists about the efficacy of site-specific treatment compared with empiric treatment in clinical practice. METHODS: In this multicentre retrospective study, we reviewed the medical records of patients with cancer of unknown primary site treated with chemotherapy (or chemoradiotherapy) as first-line treatment from eight institutions during 2006-18. We investigated the workup modality and categorized the patients into favourable and unfavourable subsets, which were further divided into site-specific and empiric treatment groups. Site-specific treatment is defined as a standard chemotherapy for an estimated primary site. We examined the efficacy in the favourable and unfavourable subsets and performed multivariable analysis for estimating the overall survival in the unfavourable subset. RESULTS: Of 177 patients with cancer of unknown primary site, 33 and 144 were categorized into favourable and unfavourable subsets, respectively. In the unfavourable subset, 84 patients (58.3%) received empiric therapy, and 60 patients (41.7%) received site-specific treatment. Median overall survival was 10.0 and 10.1 months in site-specific and empiric treatment groups, respectively, with no significant difference (hazard ratio 1.01, 95% confidence interval 0.70-1.45, P = 0.95). Multivariable analysis revealed performance status, number of metastatic sites and hypoalbuminaemia as independent prognostic factors for overall survival in the unfavourable subset. CONCLUSIONS: Overall survival in site-specific and empiric treatment groups was similar in the unfavourable cancer of unknown primary site subset in this study. Further research is needed to prolong overall survival in patients in the unfavourable cancer of unknown primary site subset.

Enhanced phosphorylation of c-Jun by cisplatin treatment as a potential predictive biomarker for cisplatin response in combination with patient-derived tumor organoids.

Despite recent advances in sequencing technology and large-scale drug screenings employing hundreds of cell lines, the predictive accuracy of mutation-based biomarkers is still insufficient as a guide for cancer therapy. Therefore, novel types of diagnostic methods using alternative biomarkers would be highly desirable. We have hypothesized that sensitivity-specific changes in the phosphorylation of signaling molecules could be useful in this respect. Here, with the aim of developing a method for predicting the response of cancers to cisplatin using a combination of specific biomarker(s) and patient-derived tumor organoids (PDOs), we found that cisplatin-sensitive cell lines or PDOs showed enhanced phosphorylation of c-Jun (p-c-Jun) within 24 h after cisplatin treatment. We also compared the responses of 6 PDOs to cisplatin with the therapeutic effect of neoadjuvant chemotherapy (docetaxel/cisplatin/5-fluorouracil) in 6 matched patients. Mechanistically, the c-Jun induction was partly related to TNF signaling induced by cisplatin. Our data suggest that enhanced phosphorylation of c-Jun in response to cisplatin treatment could be a predictive biomarker for the efficacy of cisplatin in selected cancer patients.

[Successful delivery after chemotherapy for acute myeloid leukemia diagnosed in the second trimester].

Development of acute myeloid leukemia (AML) during pregnancy is rare, and the available data are limited to small retrospective reports. Currently, no guidelines exist for the management of AML during pregnancy in Japan. A 26-year-old female was diagnosed with AML at 19 weeks of gestation, received chemotherapy with daunorubicin and cytarabine, and achieved complete remission. Following the first consolidation therapy, she gave birth to a 1964-g female infant by cesarean section at 33 weeks of gestation. One week later, she was initiated on the second consolidation therapy; however, she developed a pelvic abscess during neutropenia. She underwent urgent surgery for open drainage and recovered soon after surgery. She has been in complete remission for eight months, and the daughter is healthy. Chemotherapy delivered after the second trimester rarely causes congenital malformations and may not require the termination of pregnancy. The clinical course of the present case suggests that chemotherapy can be performed safely and effectively in pregnant patients with AML after the trimester and babies.

Febrile Neutropenia in a Patient with Non-Small Cell Lung Cancer Treated with the Immune-Checkpoint Inhibitor Nivolumab.

BACKGROUND Nivolumab is a human IgG4 monoclonal antibody against human programmed cell death 1 (PD-1). It has demonstrated efficacy against metastatic non-small cell lung cancer (NSCLC). Treatment with nivolumab is sometimes associated with immune-related adverse events (ir AEs) in patients. These specific ir AEs include pneumonitis, hypothyroidism, dermatitis, enterocolitis, hepatitis, and neuropathy. However, hematological toxicity is rare. CASE REPORT A 57-year-old man with lung adenocarcinoma, with brain and adrenal gland metastases, was therefore started on nivolumab therapy as third-line treatment. After administration of the second dose with nivolumab, grade 3 febrile neutropenia (FN) and grade 2 liver dysfunction developed in the patient. The patient was started to on intravenous antibiotics, granulocyte colony-stimulating factor (G-CSF), and corticosteroids. Neutrophil counts and liver function gradually improved, and corticosteroids were tapered over 6 weeks. However, the patient was re-treated with G-CSF because the neutrophil counts decreased again. CONCLUSIONS Care needs to be taken with such patients because neutropenia due to treatment with nivolumab can recur, as well as other ir AEs.

Correlations of cytokine levels in cerebrospinal fluid and peripheral blood with outcome of HHV-6B encephalitis after hematopoietic stem cell transplantation.

BACKGROUND: Human herpesvirus (HHV)-6B encephalitis has been recognized as a serious complication after allogeneic hematopoietic cell transplantation (allo-HCT). Little is known about the pathogenic mechanism for its progression. STUDY DESIGN: We retrospectively evaluated the 16 kinds of cytokines and chemokines in cerebrospinal fluid (CSF) and plasma in patients who developed HHV-6B encephalitis. Among a total of 20 patients, 12 were categorized as the poor prognosis group (died of encephalitis; n = 8 and retained sequelae; n = 4), and other eight patients were categorized as the good prognosis group (complete recovery; n = 8). RESULTS: Concentrations of CSF IL-6 and IL-8 at the onset of encephalitis were significantly higher in the poor prognosis group than in the good prognosis group (median CSF IL-6, 28.27 pg/mL vs 14.32 pg/mL, P = .004; median CSF IL-8, 128.70 pg/mL vs 59.43 pg/mL, P = .043). Regarding plasma, the concentration of each cytokine at the onset of encephalitis was not significantly different between the two groups, except IL-5. However, higher levels of IL-6, IL-7, and MCP-1 and lower levels of IL-12 were observed 1 week before the development of encephalitis in patients with poor prognosis (median IL-6; 464.17 pg/mL vs 47.82 pg/mL, P = .02; median IL-12; 1.63 pg/mL vs 6.57 pg/mL, P = .03). CONCLUSION: We found that one week before onset of HHV-6B encephalitis, poor prognosis patients had high plasma concentrations of IL-6, IL-7, and MCP-1 and low concentrations of IL-12. At the onset of encephalitis, high concentrations of IL-6 and IL-8 in CSF were more common in the poor prognosis group, consistent with other evidence that IL-6 can have a role in CNS disturbances. Our findings show that specific cytokine status is associated with severe brain damage in patients with HHV-6B encephalitis, demonstrate prognostic value of plasma IL-6 concentrations, and suggest evaluation of anti-cytokine therapeutics in patients with HHV-6B encephalitis.

[Philadelphia chromosome-positive acute lymphoblastic leukemia relapsing with an anterior chamber lesion of the eye].

A 48-year-old Filipino woman underwent umbilical cord blood stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia under non-remission status. Left aqueous humor puncture was performed owing to the development of left eye pain and exacerbation of anterior eye chamber inflammation 72 days after the transplantation; this revealed the relapse of leukemia in the anterior chamber. Subsequently, the patient tested positive for peripheral blood minimal residual disease. Therefore, doctors should take note that anterior chamber disease may appear as a non-typical relapse of leukemia.

A phase I study of single-agent BEZ235 special delivery system sachet in Japanese patients with advanced solid tumors.

PURPOSE: BEZ235 is a dual kinase inhibitor of phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin, which are key components of the PI3K pathway. This was an open-label, multicenter, dose-escalation, phase I study of single-agent BEZ235 in Japanese oncology patients to determine the maximum tolerated dose (MTD) of BEZ235 based on dose-limiting toxicities (DLTs). METHODS: Dose escalation was guided by a standard 3 + 3 method and was based on DLTs observed in Cycle 1 and other safety, pharmacokinetic, and pharmacodynamic information. A total of 35 adult Japanese patients with advanced solid tumors received BEZ235 according to once daily (qd; n = 27) or twice daily (bid; n = 8) dosing schedules. RESULTS: Two DLTs, namely, allergic reaction and thrombocytopenia, were observed at 1200 and 1400 mg qd, respectively, while liver dysfunction was reported as a DLT at 400 mg bid. The most common adverse events suspected to be related to BEZ235 in both dosing schedules were diarrhea, nausea, decreased appetite, stomatitis, and thrombocytopenia. CONCLUSIONS: Although the MTD was not established, the maximum clinically tolerable dose was determined to be 1200 mg because two out of six patients required dose reduction in Cycle 2. The recommended dose was determined to be 1000 mg qd, which was comparable with the results of the first-in-human BEZ235 study in Western patients with advanced solid tumors (NCT00620594). Additionally, the tolerability of BEZ235 400 mg bid in Japanese oncology patients was confirmed in this study. CLINICALTRIALS. GOV IDENTIFIER: NCT01195376.

Rationale and design of the TRUSTY study: a randomised, multicentre, open-label phase II/III study of trifluridine/tipiracil plus bevacizumab versus irinotecan, fluoropyrimidine plus bevacizumab as second-line treatment in patients with metastatic colorectal cancer progressive during or following first-line oxaliplatin-based chemotherapy.

BACKGROUND: Trifluridine/tipiracil is an oral agent approved for the treatment of patients with metastatic colorectal cancer (mCRC). Trifluridine is an antineoplastic thymidine analogue, and tipiracil improves its bioavailability. A phase I/II C-TASK FORCE study of trifluridine/tipiracil plus bevacizumab for patients with refractory mCRC demonstrated promising efficacy results with mild toxicity profile. It is important that quality of life be preserved in patients with mCRC without compromising their prognosis. Here, we outline the TRiflUridine/tipiracil in Second-line sTudY phase II/III study (JapicCTI-173618), designed to demonstrate non-inferiority in overall survival of trifluridine/tipiracil plus bevacizumab compared with irinotecan, fluoropyrimidine and bevacizumab combination regimens as second-line treatment in patients with mCRC. PATIENTS AND METHODS: Eligible patients have confirmed unresectable advanced or recurrent colorectal adenocarcinoma and have failed to respond to first-line oxaliplatin-based chemotherapy. A total of 524 patients are to be randomly assigned (1:1 ratio) to trifluridine/tipiracil plus bevacizumab or irinotecan, fluoropyrimidine and bevacizumab and stratified according to RAS status (wild type vs mutant). The primary endpoint of the phase II part is disease control rate with trifluridine/tipiracil plus bevacizumab therapy. Secondary endpoints are response rate and safety with trifluridine/tipiracil plus bevacizumab therapy. In the phase III part, the primary endpoint is overall survival, and secondary endpoints include quality of life, progression-free survival, response rate, disease control rate, safety, time to treatment failure, time to post-study treatment failure and the proportion of patients receiving post-study treatment. The first patient was enrolled in October 2017 and the study is anticipated to be completed in 2022. CLINICAL TRIAL REGISTRATION: JapicCTI-173618 (JapicCTI).

Comparison of HHV-6 DNA detection in plasma and whole blood in allogeneic hematopoietic stem cell transplant recipients: frequent false-positive results for active HHV-6 infection using whole blood samples.

In this prospective observational study, we compared the human herpesvirus-6 (HHV-6) DNA load in serially collected paired plasma and whole blood (WB) samples from allogeneic hematopoietic stem cell transplantation (HSCT) recipients. A total of 721 paired samples were collected from 68 recipients. The positive rate for HHV-6 DNA was 9.7 and 35.0% in plasma and WB samples, respectively (P < 0.001). The correlation of HHV-6 DNA load between plasma and WB was poor (R2 = 0.250). After reaching peak levels, HHV-6 DNA showed a delayed decrease in WB in comparison with plasma (median, 28 versus 7 days, P < 0.001). We additionally tested HHV-6 mRNA status in 95 samples from eight patients. To identify positive HHV-6 mRNA, plasma HHV-6 DNA showed 55.0% sensitivity and 100% specificity, whereas WB HHV-6 DNA showed 90.0% sensitivity and 68.0% specificity. The false-positive rate for identifying positive HHV-6 mRNA was 0% for plasma HHV-6 DNA and 32.0% for WB HHV-6 DNA. Although WB was more sensitive than plasma for detecting HHV-6 reactivation, the rates of false positivity for active HHV-6 infection were higher for WB than for plasma.

[Successful treatment of secondary graft failure in a mixed-phenotype acute leukemia patient with haploidentical hematopoietic stem cell transplantation and post-transplant cyclophosphamide administration].

A 38-year-old woman in the first remission of mixed-phenotype acute leukemia underwent unrelated bone marrow transplantation from an HLA-DR-mismatched donor in the host-versus-graft (HVG) direction with myeloablative conditioning. Neutrophil engraftment was achieved and complete donor chimera was obtained on days 21 and 29 after transplantation, respectively. Subsequently, with delayed blood cell recovery, continuous transfusion was needed to replace platelets. In the CD3 peripheral blood chimerism test, the percentage of recipient cells on days 50, 63, and 80 was 27.3%, 90%, and 95% or higher, respectively. With no relapse of leukemia observed on bone marrow examination, secondary graft failure associated with autologous hematopoietic recovery was diagnosed. Bone marrow transplantation from the patient's HLA-haploidentical sister was performed because of graft failure on day 111 after the initial transplant using post-transplant cyclophosphamide (PTCy). Neutrophil engraftment was achieved and complete donor chimera was obtained on days 14 and 21 after the second transplantation, respectively. With no serious complications or acute graft versus host disease, the patient was discharged with symptomatic improvement. According to our results, retransplant using PTCy obtained from an HLA-haploidentical sibling donor is a potential treatment for graft failure.

Other Iatrogenic Immunodeficiency-associated Lymphoproliferative Disorder, Hodgkin Type, following Epstein-Barr Viral Hepatitis in a Patient with Rheumatoid Arthritis.

A 59-year-old man with an 18-year history of rheumatoid arthritis who had been treated with steroids, methotrexate, and infliximab presented with a high-grade fever, cervical lymphadenopathy, and hepatosplenomegaly. Epstein-Barr virus (EBV) hepatitis was diagnosed based on the liver histology and EBV antibody titer. The symptoms improved temporarily, but five months later, the fever, skin rash, jaundice, and thrombocytopenia relapsed. Bone marrow and liver biopsies demonstrated infiltration with Reed-Sternberg cells. Based on these findings, the patient was diagnosed with other iatrogenic immunodeficiency-associated lymphoproliferative disorder (OIIA-LPD), Hodgkin lymphoma type. This case followed a rare clinical course, in that acute hepatitis preceded the diagnosis of OIIA-LPD.

Successful Cord Blood Stem Cell Transplantation for an Adult Case of Chronic Active Epstein-Barr Virus Infection.

A 41-year-old man was referred to our hospital for treatment of anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma. Chronic active Epstein-Barr virus (CAEBV) was diagnosed based on the findings of elevated EBV antibody titers and positive EBV-DNA in the peripheral blood, and cord blood stem cell transplantation (CBT) was performed. The EBV-DNA levels in the blood fell below the limit of detection. His lymphoma relapsed on Day 165 with the appearance of eruptions, which disappeared after the withdrawal of tacrolimus. One year after transplantation, there were no signs of recurrence. This encouraging result suggests that CBT should be considered for adult cases of CAEBV with aggressive clinical manifestations.

Toxoplasmic Encephalitis with Untreated Hairy Cell Leukemia Variant.

Toxoplasmic encephalitis is a rare infectious complication in patients with hematological malignancy except for allogeneic hematopoietic stem cell transplantation (HSCT). We herein report a case of possible toxoplasmic encephalitis with untreated hairy cell leukemia variant. Magnetic resonance imaging showed multiple nodules with surrounding edema in the entire cerebrum. A polymerase chain reaction analysis for Toxoplasma gondii was negative. Her signs and symptoms fully recovered by empirical therapy with sulfadiazine and pyrimethamine. Toxoplasmic encephalitis may occur in patients who undergo non-allogeneic HSCT for hematological malignancies, even in those who have not been treated.

Reduced phosphorylation of ribosomal protein S6 is associated with sensitivity to MEK inhibition in gastric cancer cells.

Gastric cancer (GC) is characterized by amplifications of receptor tyrosine kinases (RTK) and KRAS, therefore, targeting of the RTK/KRAS downstream pathways could help to broaden the applicability of molecular targeted therapy for GC. We assembled a panel of 48 GC cell lines and screened predictors of responsiveness to inhibition of the RAF/MEK/ERK pathway, one of the RTK/KRAS downstream pathways. We found that GC cells with MET amplification or KRAS mutation, but not amplification, tended to be sensitive to MEK inhibition. However, several cell lines without RTK/KRAS alterations also showed high sensitivity to MEK inhibition. We then focused on the phosphorylation of RTK/KRAS downstream molecules to screen for predictors' sensitivity to MEK inhibition. We found that the phosphorylation level of mammalian target of rapamycin complex 1 (mTORC1) downstream molecules, including p70S6K, 4EBP1, and S6, was significantly associated with sensitivity to MEK inhibition in GC cells (P < 0.05), suggesting that mTORC1 activity is related to the sensitivity to MEK inhibition. Furthermore, the change in mTORC1 activity after MEK inhibition was also significantly associated with this sensitivity (P < 0.001). Among the mTORC1 downstream molecules, the change in S6 phosphorylation (pS6) showed the most significant correlation with sensitivity. Using xenograft models derived from highly sensitive and resistant cell lines, we found specific reduction of pS6 in xenografts from highly sensitive cell lines after 6 h of treatment with an MEK inhibitor. Thus, our data suggest the potential clinical applicability of an MEK inhibitor for a proportion of GC patients who could be selected on the basis of pS6 change after MEK inhibition.

Two Elderly Patients with Philadelphia Chromosome Positive Mixed Phenotype Acute Leukemia Who Were Successfully Treated with Dasatinib and Prednisolone.

Philadelphia chromosome positive (Ph+) mixed phenotype acute leukemia (MPAL) is a rare type of acute leukemia having both myeloid and lymphoid features for which no optimal treatment has yet been established. We herein describe two elderly Ph+MPAL patients who achieved molecular remission without any serious adverse events by treatment with dasatinib and prednisolone. Although dasatinib induction therapy combined with prednisolone is known to be a highly effective treatment for Ph+ acute lymphoblastic leukemia, its efficacy for Ph+MPAL has not been shown. The clinical courses of the present cases suggest that combination therapy with dasatinib and prednisolone is a safe and effective therapeutic modality in elderly Ph+MPAL patients.

Genomic Loss of DUSP4 Contributes to the Progression of Intraepithelial Neoplasm of Pancreas to Invasive Carcinoma.

The progression from precursor lesions of pancreatic cancer, including pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasm (IPMN), to invasive disease is characterized by stepwise accumulation of genetic alterations. However, it remains unclear whether additional alterations are required for the progression of high-grade neoplasms to invasive pancreatic carcinoma. We compared the genomic profiles of paired noninvasive and invasive carcinoma tissues collected from patients with IPMN. We demonstrate that the frequency of genomic copy-number aberrations significantly increased during the course of invasion, and the loss of 8p11.22-ter was more often associated with invasive tissues. Expression profiling in pancreatic cancer cell lines with and without 8p11.22-ter revealed that DUSP4, an MAPK phosphatase, was significantly downregulated in cells lacking 8p11.22-ter as well as in invasive carcinomas due to genomic loss. Restoration of DUSP4 expression in pancreatic cancer cells significantly suppressed invasiveness and anoikis resistance via ERK inactivation. Accordingly, we found that blockade of ERK signaling by MEK inhibition was effective in an orthotopic xenograft model and significantly extended survival. Collectively, our findings demonstrate a genetic mechanism by which pancreatic precursor lesions progress to invasive carcinomas and highlight DUSP4 as a novel invasion suppressor that can be therapeutically exploited through manipulation of ERK signaling. Cancer Res; 76(9); 2612-25. ©2016 AACR.