Salicylates enhance CRM1 inhibitor antitumor activity by induction of S-phase arrest and impairment of DNA-damage repair.

Chromosome region maintenance protein 1 (CRM1) mediates protein export from the nucleus and is a new target for anticancer therapeutics. Broader application of KPT-330 (selinexor), a first-in-class CRM1 inhibitor recently approved for relapsed multiple myeloma and diffuse large B-cell lymphoma, have been limited by substantial toxicity. We discovered that salicylates markedly enhance the antitumor activity of CRM1 inhibitors by extending the mechanisms of action beyond CRM1 inhibition. Using salicylates in combination enables targeting of a range of blood cancers with a much lower dose of selinexor, thereby potentially mitigating prohibitive clinical adverse effects. Choline salicylate (CS) with low-dose KPT-330 (K+CS) had potent, broad activity across high-risk hematological malignancies and solid-organ cancers ex vivo and in vivo. The K+CS combination was not toxic to nonmalignant cells as compared with malignant cells and was safe without inducing toxicity to normal organs in mice. Mechanistically, compared with KPT-330 alone, K+CS suppresses the expression of CRM1, Rad51, and thymidylate synthase proteins, leading to more efficient inhibition of CRM1-mediated nuclear export, impairment of DNA-damage repair, reduced pyrimidine synthesis, cell-cycle arrest in S-phase, and cell apoptosis. Moreover, the addition of poly (ADP-ribose) polymerase inhibitors further potentiates the K+CS antitumor effect. K+CS represents a new class of therapy for multiple types of blood cancers and will stimulate future investigations to exploit DNA-damage repair and nucleocytoplasmic transport for cancer therapy in general.

PFKFB3 works on the FAK-STAT3-SOX2 axis to regulate the stemness in MPM.

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm and often acquires chemoresistance by increasing stemness in tumour tissue, thereby generating cancer stem cells (CSCs). CSCs escape treatment by deploying metabolic pathways to trigger dormancy or proliferation, also gaining the ability to exit and re-enter the cell cycle to hide their cellular identity. METHODS: We employed various cellular and biochemical assays to identify the role of the glycolytic enzyme PFKFB3, by knocking it down and pharmacologically inhibiting it with PFK158, to determine its anticancer effects in vitro and in vivo by targeting the CSC population in MPM. RESULTS: Here, we have identified PFKFB3 as a strategic player to target the CSC population in MPM and demonstrated that both pharmacologic (PFK158) and genetic inhibition of PFKFB3 destroy the FAK-Stat3-SOX2 nexus resulting in a decline in conspicuous stem cell markers viz. ALDH, CD133, CD44, SOX2. Inhibition of PFKFB3 accumulates p21 and p27 in the nucleus by decreasing SKP2. Lastly, PFK158 diminishes tumour-initiating cells (TICs) mediated MPM xenograft in vivo. CONCLUSIONS: This study confers a comprehensive and mechanistic function of PFKFB3 in CSC maintenance that may foster exceptional opportunities for targeted small molecule blockade of the TICs in MPM.

A Phase II Study of Pazopanib in Patients with Malignant Pleural Mesothelioma: NCCTG N0623 (Alliance).

PURPOSE: Preclinical and clinical data have shown promise in using antiangiogenic agents to treat malignant pleural mesothelioma (MPM). We conducted this phase II study to evaluate the efficacy and toxicity of single-agent pazopanib in patients with MPM. MATERIALS AND METHODS: Patients with MPM who had received 0-1 prior chemotherapy regimens were eligible to receive pazopanib at a dose of 800 mg daily. The primary endpoint was progression-free survival rate at 6 months (PFS6), with a preplanned interim analysis for futility. Secondary endpoints included overall survival (OS), PFS, adverse events assessment and clinical benefit (complete response, partial response [PR], and stable disease [SD]). RESULTS: Thirty-four evaluable patients were enrolled, with a median age of 73 years (49-84). The trial was closed early because of lack of efficacy at the preplanned interim analysis. Only 8 patients (28.6%; 95% confidence interval [CI], 13.2-48.7%) in the first 28 evaluable were progression-free at 6 months. PFS6 was 32.4% (95% CI, 17.4-50.5). There were 2 PR (5.9%) and 16 SD (47.1%). The overall median PFS and OS were 4.2 months (95% CI, 2.0-6.0) and 11.5 months (95% CI: 5.3-18.2), respectively. The median PFS and OS for the previously untreated patients was 5.4 months (95% CI, 2.7-8.5) and 16.6 months (95% CI, 6.6-30.6), respectively; and 2.0 months (95% CI, 1.3-4.2) and 5.0 months (95% CI: 3.0-11.9), respectively, for the previously treated patients. Grade 3 or higher adverse events were observed in 23 patients (67.6%). CONCLUSION: Single-agent pazopanib was poorly tolerated in patients with MPM. The primary endpoint of PFS6 was not achieved in the current study. ClinicalTrials.gov identification number. NCT00459862. IMPLICATIONS FOR PRACTICE: Single-agent pazopanib did not meet its endpoint in this phase II trial in malignant mesothelioma. Pazopanib is well tolerated in mesothelioma patients with a manageable toxicity profile. There is a need to better identify signals of angiogenesis that can be targeted in mesothelioma. Encouraging findings in frontline treatment warrant further investigations in combination with chemotherapy or immunotherapy.

A phase I study of the VEGFR kinase inhibitor vatalanib in combination with the mTOR inhibitor, everolimus, in patients with advanced solid tumors.

Purpose Combining small-molecule inhibitors of different targets was shown to be synergistic in preclinical studies. Testing this concept in clinical trials is, however, daunting due to challenges in toxicity management and efficacy assessment. This study attempted to evaluate the safety and efficacy of vatalanib plus everolimus in patients with advanced solid tumors and explore the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) studies as a predictive biomarker. Patients and Methods This single-center, phase I trial containing 70 evaluable patients consisted of a dose escalation proportion based on the traditional "3 + 3" design (cohort IA and IB) and a dose expansion proportion (cohort IIA and IIB). Toxicity was evaluated using the Common Terminology Criteria of Adverse Events. Antitumor activity was assessed using the Modified Response Evaluation Criteria in Solid Tumors. Results The maximum tolerated doses were determined to be vatalanib 1250 mg once daily or 750 mg twice daily in combination with everolimus 10 mg once daily. No treatment-related death occurred. The most common toxicities were hypertriglyceridemia, hypercholesterolemia, fatigue, vomiting, nausea and diarrhea. There was no complete response. Nine patients (12.9%) had partial response (PR) and 41 (58.6%) had stable disease (SD). Significant antitumor activity was observed in neuroendocrine tumors with a disease-control rate (PR + SD) of 66.7% and other tumor types including renal cancer, melanoma, and non-small-cell lung cancer. Conclusions The combination of vatalanib and everolimus demonstrated reasonable toxicity and clinical activity. Future studies combining targeted therapies and incorporating biomarker analysis are warranted based on this phase I trial.

Phase 1 trial of Vismodegib and Erlotinib combination in metastatic pancreatic cancer.

BACKGROUND/OBJECTIVES: Interplay between the Hedgehog (HH) and epidermal growth factor receptor (EGFR) pathways modulating the outcome of their signaling activity have been reported in various cancers including pancreatic ductal adenocarcinoma (PDAC). Therefore, simultaneous targeting of these pathways may be clinically beneficial. This Phase I study combined HH and EGFR inhibition in metastatic PDAC patients. METHODS: Combined effects of HH and EGFR inhibition using Vismodegib and Erlotinib with or without gemcitabine in metastatic solid tumors were assessed by CT. Another cohort of patients with metastatic PDAC was evaluated by FDG-PET and tumor biopsies-derived biomarkers. RESULTS: Treatment was well tolerated with the maximum tolerated dose cohort experiencing no grade 4 toxicities though 25% experienced grade 3 adverse effects. Recommended phase II dose of Vismodegib and Erlotinib were each 150 mg daily. No tumor responses were observed although 16 patients achieved stable disease for 2-7 cycles. Paired biopsy analysis before and after first cycle of therapy in PDAC patients showed reduced GLI1 mRNA, phospho-GLI1 and associated HH target genes in all cases. However, only half of the cases showed reduced levels of desmoplasia or changes in fibroblast markers. Most patients had decreased phospho-EGFR levels. CONCLUSIONS: Vismodegib and Erlotinib combination was well-tolerated although overall outcome in patients with metastatic PDAC was not significantly impacted by combination treatment. Biomarker analysis suggests direct targets inhibition without significantly affecting the stromal compartment. These findings conflict with pre-clinical mouse models, and thus warrant further investigation into how upstream inhibition of these pathways is circumvented in PDAC.

Pulmonary Neuroendocrine Tumors: Adjuvant and Systemic Treatments.

OPINION STATEMENT: Bronchial carcinoids are uncommon tumors accounting for 20 to 30% of all neuroendocrine tumors and about 1-2% of all cancers of pulmonary origin. Bronchial carcinoids are well-differentiated neuroendocrine tumors and have a favorable survival outcome when compared with other subtypes of lung cancers. Treatment of bronchial carcinoids is not simple owing to intricacy of symptom presentation and heterogeneity of disease biology. Successful treatment of patients requires a multimodality approach. Resection is curative in the majority of patients with localized tumors and adjuvant treatment is not routinely recommended. Multiple options for systemic therapy exist for patients with advanced disease. To date, very few randomized clinical trials have been done, partly owing to the relative rarity of this malignancy. Somatostatin analogs (SSAs) are reasonable first-line choice for patients with tumors expressing somatostatin receptors. Everolimus is an appropriate first-line choice for somatostatin receptor negative tumors and for any patients with progressive disease. PRRT can also be considered for progressive tumors expressing somatostatin receptors. Based on retrospective series, cytotoxic chemotherapy can be selected in patients with progressive tumors, primarily when cytoreduction is needed. Herein, we will discuss evidence supporting the role of adjuvant and systemic treatment therapies for those with bronchial carcinoid tumors by focusing on various studies.

Characterization of Comorbidities Limiting the Recruitment of Patients in Early Phase Clinical Trials.

BACKGROUND: Early phase clinical trials evaluate the safety and efficacy of new treatments. The exclusion/inclusion criteria in these trials are usually rigorous and may exclude many patients seen in clinical practice. Our objective was to study the comorbidities limiting the participation of patients with breast, colorectal, or lung cancer in clinical trials. MATERIALS AND METHODS: We queried ClinicalTrials.gov on December 31, 2016. We reviewed the eligibility criteria of 1,103 trials. Logistic regression analyses were completed, and exclusion was studied as a binary variable. RESULTS: Out of 1,103 trials, 70 trials (6%) excluded patients >75 years of age, and 45% made no reference to age. Eighty-six percent of trials placed restrictions on patients with history of prior malignancies. Regarding central nervous system (CNS) metastasis, 416 trials (38%) excluded all patients with CNS metastasis, and 373 (34%) only allowed asymptomatic CNS metastasis. Regarding chronic viral infections, 347 trials (31%) excluded all patients with human immunodeficiency virus, and 228 trials (21%) excluded all patients with hepatitis B or C infection. On univariate analysis, chemotherapy trials were more likely to exclude patients with CNS metastasis and history of other malignancies than targeted therapy trials. Multivariate analysis demonstrated that industry-sponsored trials had higher odds of excluding patients with compromised liver function. CONCLUSION: Many clinical trials excluded large segments of the population of patients with cancer. Frequent exclusion criteria included patients with CNS metastasis, history of prior malignancies, and chronic viral infections. The criteria for participation in some clinical trials may be overly restrictive and limit enrollment. IMPLICATIONS FOR PRACTICE: The results of this study revealed that most early phase clinic trials contain strict exclusion criteria, potentially excluding the patients who may be more likely to represent the population treated in clinical settings, leaving patients susceptible to unintended harm from inappropriate generalization of trial results. Careful liberalization of the inclusion/exclusion criteria in clinical trials will allow investigators to understand the benefits and drawbacks of the experimental drug for a broader population, and possibly improve recruitment of patients with cancer into clinical trials.

digit-a tool for detection and identification of genomic interchromosomal translocations.

Structural variations (SVs) in genomic DNA can have profound effects on the evolution of living organisms, on phenotypic variations and on disease processes. A critical step in discovering the full extent of structural variations is the development of tools to characterize these variations accurately in next generation sequencing data. Toward this goal, we developed a software pipeline named digit that implements a novel measure of mapping ambiguity to discover interchromosomal SVs from mate-pair and pair-end sequencing data. The workflow robustly handles the high numbers of artifacts present in mate-pair sequencing and reduces the false positive rate while maintaining sensitivity. In the simulated data set, our workflow recovered 96% of simulated SVs. It generates a self-updating library of common translocations and allows for the investigation of patient- or group-specific events, making it suitable for discovering and cataloging chromosomal translocations associated with specific groups, traits, diseases or population structures.

The DNA Methyltransferase DNMT1 and Tyrosine-Protein Kinase KIT Cooperatively Promote Resistance to 5-Aza-2'-deoxycytidine (Decitabine) and Midostaurin (PKC412) in Lung Cancer Cells.

Lung cancer cells are sensitive to 5-aza-2'-deoxycytidine (decitabine) or midostaurin (PKC412), because decitabine restores the expression of methylation-silenced tumor suppressor genes, whereas PKC412 inhibits hyperactive kinase signaling, which is essential for cancer cell growth. Here, we demonstrated that resistance to decitabine (decitabine(R)) or PKC412 (PKC412(R)) eventually results from simultaneously remethylated DNA and reactivated kinase cascades. Indeed, both decitabine(R) and PKC412(R) displayed the up-regulation of DNA methyltransferase DNMT1 and tyrosine-protein kinase KIT, the enhanced phosphorylation of KIT and its downstream effectors, and the increased global and gene-specific DNA methylation with the down-regulation of tumor suppressor gene epithelial cadherin CDH1. Interestingly, decitabine(R) and PKC412(R) had higher capability of colony formation and wound healing than parental cells in vitro, which were attributed to the hyperactive DNMT1 or KIT, because inactivation of KIT or DNMT1 reciprocally blocked decitabine(R) or PKC412(R) cell proliferation. Further, DNMT1 knockdown sensitized PKC412(R) cells to PKC412; conversely, KIT depletion synergized with decitabine in eliminating decitabine(R). Importantly, when engrafted into nude mice, decitabine(R) and PKC412(R) had faster proliferation with stronger tumorigenicity that was caused by the reactivated KIT kinase signaling and further CDH1 silencing. These findings identify functional cross-talk between KIT and DNMT1 in the development of drug resistance, implying the reciprocal targeting of protein kinases and DNA methyltransferases as an essential strategy for durable responses in lung cancer.

Comprehensive Genomic Profiling Identifies a Subset of Crizotinib-Responsive ALK-Rearranged Non-Small Cell Lung Cancer Not Detected by Fluorescence In Situ Hybridization.

INTRODUCTION: For patients with non-small cell lung cancer (NSCLC) to benefit from ALK inhibitors, sensitive and specific detection of ALK genomic rearrangements is needed. ALK break-apart fluorescence in situ hybridization (FISH) is the U.S. Food and Drug Administration approved and standard-of-care diagnostic assay, but identification of ALK rearrangements by other methods reported in NSCLC cases that tested negative for ALK rearrangements by FISH suggests a significant false-negative rate. We report here a large series of NSCLC cases assayed by hybrid-capture-based comprehensive genomic profiling (CGP) in the course of clinical care. MATERIALS AND METHODS: Hybrid-capture-based CGP using next-generation sequencing was performed in the course of clinical care of 1,070 patients with advanced lung cancer. Each tumor sample was evaluated for all classes of genomic alterations, including base-pair substitutions, insertions/deletions, copy number alterations and rearrangements, as well as fusions/rearrangements. RESULTS: A total of 47 patients (4.4%) were found to harbor ALK rearrangements, of whom 41 had an EML4-ALK fusion, and 6 had other fusion partners, including 3 previously unreported rearrangement events: EIF2AK-ALK, PPM1B-ALK, and PRKAR1A-ALK. Of 41 patients harboring ALK rearrangements, 31 had prior FISH testing results available. Of these, 20 were ALK FISH positive, and 11 (35%) were ALK FISH negative. Of the latter 11 patients, 9 received crizotinib based on the CGP results, and 7 achieved a response with median duration of 17 months. CONCLUSION: Comprehensive genomic profiling detected canonical ALK rearrangements and ALK rearrangements with noncanonical fusion partners in a subset of patients with NSCLC with previously negative ALK FISH results. In this series, such patients had durable responses to ALK inhibitors, comparable to historical response rates for ALK FISH-positive cases. IMPLICATIONS FOR PRACTICE: Comprehensive genomic profiling (CGP) that includes hybrid capture and specific baiting of intron 19 of ALK is a highly sensitive, alternative method for identification of drug-sensitive ALK fusions in patients with non-small cell lung cancer (NSCLC) who had previously tested negative using standard ALK fluorescence in situ hybridization (FISH) diagnostic assays. Given the proven benefit of treatment with crizotinib and second-generation ALK inhibitors in patients with ALK fusions, CGP should be considered in patients with NSCLC, including those who have tested negative for other alterations, including negative results using ALK FISH testing.

c-Met expression and MET amplification in malignant pleural mesothelioma.

c-Met is a receptor tyrosine kinase shown to be overexpressed in malignant pleural mesothelioma (MPM). Whereas MET mutations have been identified in 3%-16% of MPMs, MET amplification has recently been reported in a single epithelioid MPM. We studied c-Met expression and MET amplification in a large MPM cohort and correlated results with morphologic and clinical features. We report the first case of MET amplification in sarcomatoid MPM. MPMs from surgical pathology files (1989-2014) were reviewed. c-Met immunohistochemistry was performed. Staining intensity and distribution were multiplied (H-score). Staining localization (cytoplasmic and/or membranous) was noted. Fluorescence in situ hybridization was performed using probes for MET and centromere 7. One hundred forty-nine patients (median age, 68.0years; interquartile range, 61-75) had epithelioid (n=97), biphasic (n=18), or sarcomatoid (n=34) MPM. Median follow-up was 10.1months (range, 0.1-222.5). One hundred thirty patients died of disease; 2 were alive with disease. c-Met was expressed in 147 MPMs. c-Met staining intensity, distribution, and H-score differed among the histologic subtypes (P=.015; P=.0001, and P=.0005, respectively), but none were predictive of survival. Epithelioid subtype had greater c-Met expression. MET amplification was identified in 1 sarcomatoid MPM and MET duplication in 1 epithelioid MPM; both had poor outcomes. Chromosome 7 aneusomy was observed in 54 of 144 (37.5%) MPMs and associated with decreased overall survival in sarcomatoid MPMs (hazard ratio=2.81; 95% confidence interval, 1.21-6.51; P=.01). In conclusion, c-Met is expressed in MPM, with significant differences in expression among histologic subtypes. MET amplification is a rare event in MPM, making it an unlikely common pathogenesis for c-Met expression.

Concurrent MCL1 and JUN amplification in pseudomyxoma peritonei: a comprehensive genetic profiling and survival analysis.

Pseudomyxoma peritonei (PMP) is a rare abdominal malignancy. We hypothesized that next-generation exomic sequencing would identify recurrent mutations that may have prognostic or therapeutic implications. Ten patients were selected on the basis of availability of tissue and adequate follow-up. They were treated at our institution between September 2002 and August 2004. Using next-generation exomic sequencing, we tested for mutations in 236 cancer-related genes in formalin-fixed paraffin-embedded slides. MCL1 amplification was additionally tested with immunohistochemical staining. Detectable mutations were found in 8 patients (80%). Seven patients harbored a KRAS mutation, most commonly involving codon 12. Four GNAS mutations (R201H/R201C substitutions) were also detected. MCL1 and JUN were concurrently amplified in three patients. One patient with MCL1 and JUN amplification had concurrent amplification of MYC and NFKBIA. ZNF703 was amplified in one patient. Patients with MCL1 amplification were also found to express MCL1 with immunohistochemistry, but MCL1 expression was also detected in some patients without amplification. To our knowledge, we are the first to report MCL1 and JUN coamplification in PMP. Expression of MCL1 may not be completely dependent on amplification. The prognostic and therapeutic implications of these recurrent mutational events are the subject of ongoing investigation.

Advancing head and neck cancer management: Unveiling the diagnostic and therapeutic potentials of molecular profiling.

BACKGROUND: Head and neck cancers (HNC) present diagnostic challenges due to multifocal disease manifestations, posing difficulties in distinguishing between metastatic disease and second primary malignancies (SPM). This complexity underscores the need for advanced diagnostic approaches. Emerging technologies, such as next-generation sequencing (NGS) and molecular classifier assays, show promise in providing precise insights into the diverse etiologies of HNC. METHOD: In this article, we employed NGS and molecular classifier assays to delve into three distinct clinical cases. The objective was to showcase the instrumental role of these technologies in facilitating accurate diagnoses and differentiating between metastatic disease and SPM in HNC cases. RESULTS: The results of this series highlight the effectiveness of NGS and molecular classifier assays in enhancing diagnostic accuracy for HNC and contributing to the precise differentiation of disease etiologies. The utilization of these advanced technologies proved instrumental in avoiding unnecessary interventions and paved the way for more targeted and effective treatment strategies. CONCLUSION: Our findings underscore the necessity of incorporating advanced molecular testing technologies into the diagnostic and therapeutic approaches for HNC, thereby championing a more nuanced and effective approach to managing these complex cases.

Detecting HLA loss of heterozygosity within a standard diagnostic sequencing workflow for prognostic and therapeutic opportunities.

To enable interrogation of tumor HLA LOH as a clinical diagnostic for precision oncology, we developed and validated an assay that detects HLA LOH within the context of an FDA-approved clinical diagnostic test, Tempus xT CDx. Validation was conducted via: (1) analytical evaluation of 17 archival patient samples and 42 cell line admixtures and (2) independent clinical evaluation of LOH prevalence in the HLA-A gene (HLA-A LOH) across 10,982 patients. To evaluate the prognostic relevance of HLA-A LOH we assessed 256 immunotherapy-treated non-small cell lung cancer (NSCLC) patients. To determine the feasibility of prospectively identifying and enrolling HLA-A LOH patients into a clinical trial, we established BASECAMP-1 (NCT04981119). We observed a positive predictive agreement of 97% and a negative predictive agreement of 100% in samples with ≥ 40% tumor purity. We observed HLA-A LOH in 16.1% of patients (1771/10,982), comparable to previous reports. HLA-A LOH was associated with longer survival among NSCLC adenocarcinoma patients (HR = 0.60, 95% CI [0.37, 0.96], p = 0.032) with a trend towards shorter survival among squamous cell patients (HR = 1.64, 95% CI [0.80, 3.41], p = 0.183). In 20 months, we prospectively screened 1720 subjects using the Tempus AWARE program, identifying 26 HLA-A*02 LOH patients at 8 sites, with 14 (54%) enrolled into BASECAMP-1. In conclusion, we developed and validated an investigational assay that detects tumor HLA LOH within an FDA-approved clinical diagnostic test, enabling HLA LOH utilization in diagnostic, prognostic, and therapeutic applications.

Phase I dose escalation study of the PKCι inhibitor aurothiomalate for advanced non-small-cell lung cancer, ovarian cancer, and pancreatic cancer.

Protein kinase C iota (PKCι) is overexpressed in non-small-cell lung cancer, ovarian, and pancreatic cancers, where it plays a critical role in oncogenesis. The gold compound aurothiomalate (ATM) has been shown to inhibit PKCι signaling and exerts potent antitumor activity in preclinical models. We sought to determine the maximum tolerated dose (MTD) of ATM. We conducted a phase I dose escalation trial of ATM in patients with non-small-cell lung cancer, ovarian or pancreatic cancer. Patients received ATM intramuscularly weekly for three cycles (cycle duration 4 weeks) at 25, 50, or 75 mg in a 3+3 design. The dose was not escalated for individual patients. Blood samples were analyzed for elemental gold levels. Patients were evaluated every 4 weeks for toxicity and every 8 weeks for response. Fifteen patients were enrolled in this study. Six patients were treated at 25 mg, seven at 50 mg, and two at 75 mg. There was one dose-limiting toxicity at 25 mg (hypokalemia), one at 50 mg (urinary tract infection), and none at 75 mg. There were three grade 3 hematologic toxicities. The recommended MTD of ATM is 50 mg. Patients received treatment for a median of two cycles (range 1-3). There appeared to be a dose-related accumulation of steady-state plasma concentrations of gold consistent with linear pharmacokinetics. In summary, this phase I study was successful in identifying ATM 50 mg intramuscularly weekly as the MTD. Future clinical investigations targeting PKCι are currently in progress.

Ectopic expression of VAV1 reveals an unexpected role in pancreatic cancer tumorigenesis.

Herein, we show that the hematopoietic-specific GEF VAV1 is ectopically expressed in primary pancreatic adenocarcinomas due to demethylation of the gene promoter. Interestingly, VAV1-positive tumors had a worse survival rate compared to VAV1-negative tumors. Surprisingly, even in the presence of oncogenic KRAS, VAV1 RNAi abrogates neoplastic cellular proliferation in vitro and in vivo, thus identifying Vav1 as a growth-stimulatory protein in this disease. Vav1 acts synergistically with the EGF receptor to stimulate pancreatic tumor cell proliferation. Mechanistically, the effects of Vav1 require its GEF activity and the activation of Rac1, PAK1, and NF-kappaB and involve cyclin D1 upregulation. Thus, the discovery of prooncogenic pathways regulated by Vav1 makes it an attractive target for therapeutic intervention.

EZH2 and POU2F3 Can Aid in the Distinction of Thymic Carcinoma from Thymoma.

Thymic carcinoma is an aggressive malignancy that can be challenging to distinguish from thymoma using histomorphology. We assessed two emerging markers for these entities, EZH2 and POU2F3, and compared them with conventional immunostains. Whole slide sections of 37 thymic carcinomas, 23 type A thymomas, 13 type B3 thymomas, and 8 micronodular thymomas with lymphoid stroma (MNTLS) were immunostained for EZH2, POU2F3, CD117, CD5, TdT, BAP1, and MTAP. POU2F3 (≥10% hotspot staining), CD117, and CD5 showed 100% specificity for thymic carcinoma versus thymoma with 51%, 86%, and 35% sensitivity, respectively, for thymic carcinoma. All POU2F3 positive cases were also positive for CD117. All thymic carcinomas showed >10% EZH2 staining. EZH2 (≥80% staining) had a sensitivity of 81% for thymic carcinoma and a specificity of 100% for thymic carcinoma versus type A thymoma and MNTLS but had poor specificity (46%) for thymic carcinoma versus B3 thymoma. Adding EZH2 to a panel of CD117, TdT, BAP1, and MTAP increased cases with informative results from 67/81 (83%) to 77/81 (95%). Overall, absent EZH2 staining may be useful for excluding thymic carcinoma, diffuse EZH2 staining may help to exclude type A thymoma and MNTLS, and ≥10% POU2F3 staining has excellent specificity for thymic carcinoma versus thymoma.

PFKFB3 regulates cancer stemness through the hippo pathway in small cell lung carcinoma.

PFKFB3 (6-phosphofructo-2-kinase) is the rate-limiting enzyme of glycolysis and is overexpressed in several human cancers that are associated with poor prognosis. High PFKFB3 expression in cancer stem cells promotes glycolysis and survival in the tumor microenvironment. Inhibition of PFKFB3 by the glycolytic inhibitor PFK158 and by shRNA stable knockdown in small cell lung carcinoma (SCLC) cell lines inhibited glycolysis, proliferation, spheroid formation, and the expression of cancer stem cell markers CD133, Aldh1, CD44, Sox2, and ABCG2. These factors are also associated with chemotherapy resistance. We found that PFK158 treatment and PFKFB3 knockdown enhanced the ABCG2-interacting drugs doxorubicin, etoposide, and 5-fluorouracil in reducing cell viability under conditions of enriched cancer stem cells (CSC). Additionally, PFKFB3 inhibition attenuated the invasion/migration of SCLC cells by downregulating YAP/TAZ signaling while increasing pLATS1 via activation of pMST1 and NF2 and by reducing the mesenchymal protein expression. PFKFB3 knockdown and PFK158 treatment in a H1048 SCLC cancer stem cell-enriched mouse xenograft model showed significant reduction in tumor growth and weight with reduced expression of cancer stem cell markers, ABCG2, and YAP/TAZ. Our findings identify that PFKFB3 is a novel target to regulate cancer stem cells and its associated therapeutic resistance markers YAP/TAZ and ABCG2 in SCLC models.

Efficacy of immune checkpoint inhibitors in non-small cell lung cancer: A systematic review and meta-analysis.

Background: Immune checkpoint inhibitors (ICIs) have demonstrated remarkable efficacy in non-small cell lung cancer (NSCLC). However, only a minority of NSCLC patients benefit from ICIs, and whether the magnitude of benefit is specific factor-dependent remains unclear. We performed a systematic review to improve our understanding of clinicopathologic and biomolecular features associated with improved survival upon treatment with ICIs for NSCLC. Methods: We searched PubMed, Web of Science, Embase, and Scopus from database inception to August 31, 2021, for randomized controlled trials (RCTs) comparing overall survival (OS) in NSCLC treated with ICIs vs control therapies. We calculated the pooled OS hazard ratio (HR) and 95% CI in subgroups using a random-effects model, and assessed the heterogeneity between the paired estimates using an interaction test. Results: A total of 23 RCTs involving 15,829 patients were included. We found that wild-type EGFR, high PD-L1 expression, and high bTMB were associated with a significant OS benefit from ICIs, but not mutant EGFR, low PD-L1 expression, and low bTMB. The differences of OS benefit between wild-type and mutant EGFR (HR=1.53, 95%CI 1.13-2.08), high and low PD-L1 (HR=1.35; 95%CI 1.14-1.61), high and low bTMB (HR=1.71; 95%CI 1.17-2.52) were statistically significant. OS benefit was found in all subgroups regardless of sex, age, ECOG PS, histology, smoking history, baseline brain metastasis, race, and region, and the interaction test demonstrated no significant difference of the OS benefit between these opposed subgroups (e.g. male vs female). Conclusions: Wild-type EGFR, high PD-L1 expression, and high bTMB are associated with a greater magnitude of efficacy from ICIs vs control therapies in NSCLC. However, the administration of ICIs should not be restricted to other clinicopathological factors (sex, smoking history, race, etc.).

Chemotherapy for non-small-cell lung carcinoma: from a blanket approach to individual therapy.

Only one third of patients with non-small-cell lung carcinoma (NSCLC) present with early-stage disease that is amenable to potentially curative resection and adjuvant therapy. Unfortunately, even in stage I NSCLC, 5-year survival rates are in the range of 55 to 72%. For unresectable disease in stages IIIB and IV, 5-year survival rates are < 5%. Postoperative chemotherapy (adjuvant chemotherapy) using cisplatin-based regimens has become the standard of care for resected stage II to IIIA NSCLC. However, adjuvant chemotherapy may be harmful in stage IA NSCLC, and its role for stage 1B is controversial. There are no conclusive data showing superiority of neoadjuvant chemotherapy (given prior to surgery) over adjuvant chemotherapy (given after surgery) or vice versa in early-stage NSCLC. Several emerging TARGETED therapy agents [e.g., inhibitors of vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), or tyrosine kinase], and combination chemotherapy regimens are currently being evaluated in NSCLC. Specific patient subpopulation characteristics (including EGFR mutations) may be prognostically important to identify potential responders (or nonresponders) to therapy. This review will focus on chemotherapeutic approaches to treat both early stage (adjuvant and neoadjuvant chemotherapy) and metastatic disease including the use of maintenance therapy and novel agents.