Paradigms on Immunotherapy Combinations with Chemotherapy.

Checkpoint inhibitors are being added to standard-of-care chemotherapy in multiple clinical trials. Success has been reported in non-small and small cell lung carcinomas and urothelial, head and neck, gastric, and esophageal cancers, and promising results are already available in triple-negative breast and pancreatic malignancies. The potential mechanisms of synergy include immunogenic tumor cell death, antiangiogenesis, selective depletion of myeloid immunosuppressive cells, and lymphopenia, which reduces regulatory T cells and makes room for proliferation of effector T cells. However, chemotherapy regimens have not been optimized for such combinations, perhaps explaining some recent clinical trial disappointments. Approaches to make the most of chemoimmunotherapy include neoadjuvant and adjuvant schemes.Significance: Immunotherapy of cancer based on PD-1/PD-L1 blockade has prompted a revolution in cancer clinical management. Evidence in phase III clinical trials already supports combinations of immunotherapy with standard-of-care chemotherapy for a number of malignant diseases. This review focuses on such evidence and provides an overview of the potential synergistic mechanisms of action and the opportunities to optimize chemoimmunotherapy regimens.

Performance comparison of two next-generation sequencing panels to detect actionable mutations in cell-free DNA in cancer patients.

Background Genomic alterations studies in cell-free DNA (cfDNA) have increasing clinical use in oncology. Next-generation sequencing (NGS) technology provides the most complete mutational analysis, but nowadays limited data are available related to the comparison of results reported by different platforms. Here we compare two NGS panels for cfDNA: Oncomine™ Pan-Cancer Cell-Free Assay (Thermo Fisher Scientific), suitable for clinical laboratories, and Guardant360® (GuardantHealth), with more genes targeted but only available in an outsourcing laboratory. Methods Peripheral blood was obtained from 16 advanced cancer patients in which Guardant360® (G360) was requested as part of their clinical assistance. Blood samples were sent to be analyzed with G360 panel, and an additional blood sample was drawn to obtain and analyze cfDNA with Oncomine™ Pan-Cancer (OM) panel in an Ion GeneStudio S5™ System. Results cfDNA analysis globally rendered 101 mutations. Regarding the 55/101 mutations claimed to be included by manufacturers in both panels, 17 mutations were reported only by G360, 10 only by OM and 28 by both. In those coincident cases, there was a high correlation between the variant allele fractions (VAFs) calculated with each panel (r = 0.979, p < 0.01). Regarding the six actionable mutations with an FDA-approved therapy reported by G360, one was missed with OM. Also, 12 mutations with clinical trials available were reported by G360 but not by OM. Conclusions In summary, G360 and OM can produce different mutational profile in the same sample, even in genes included in both panels, which is especially important if these mutations are potentially druggable.

Short-term starvation reduces IGF-1 levels to sensitize lung tumors to PD-1 immune checkpoint blockade.

Harnessing the immune system by blocking the programmed cell death protein 1 (PD-1) pathway has been a major breakthrough in non-small-cell lung cancer treatment. Nonetheless, many patients fail to respond to PD-1 inhibition. Using three syngeneic models, we demonstrate that short-term starvation synergizes with PD-1 blockade to inhibit lung cancer progression and metastasis. This antitumor activity was linked to a reduction in circulating insulin-like growth factor 1 (IGF-1) and a downregulation of IGF-1 receptor (IGF-1R) signaling in tumor cells. A combined inhibition of IGF-1R and PD-1 synergistically reduced tumor growth in mice. This effect required CD8 cells, boosted the intratumoral CD8/Treg ratio and led to the development of tumor-specific immunity. In patients with non-small-cell lung cancer, high plasma levels of IGF-1 or high IGF-1R expression in tumors was associated with resistance to anti-PD-1-programmed death-ligand 1 immunotherapy. In conclusion, our data strongly support the clinical evaluation of IGF-1 modulators in combination with PD-1 blockade.

Safety and Efficacy of Nivolumab Monotherapy in Recurrent or Metastatic Cervical, Vaginal, or Vulvar Carcinoma: Results From the Phase I/II CheckMate 358 Trial.

PURPOSE: Nivolumab was assessed in patients with virus-associated tumors in the phase I/II CheckMate 358 trial (ClinicalTrials.gov identifier: NCT02488759). We report on patients with recurrent/metastatic cervical, vaginal, or vulvar cancers. PATIENTS AND METHODS: Patients received nivolumab 240 mg every 2 weeks. Although patients with unknown human papillomavirus status were enrolled, patients known to have human papillomavirus-negative tumors were ineligible. The primary end point was objective response rate. Duration of response (DOR), progression-free survival, and overall survival were secondary end points. Safety and patient-reported outcomes were exploratory end points. RESULTS: Twenty-four patients (cervical, n = 19; vaginal/vulvar, n = 5) were enrolled. Most patients had received prior systemic therapy for metastatic disease (cervical, 78.9%; vaginal/vulvar, 80.0%). Objective response rates were 26.3% (95% CI, 9.1 to 51.2) for cervical cancer and 20.0% (95% CI, 0.5 to 71.6) for vaginal/vulvar cancers. At a median follow-up of 19.2 months, median DOR was not reached (range, 23.3 to 29.5+ months; + indicates a censored observation) in the five responding patients in the cervical cohort; the DOR was 5.0 months in the single responding patient in the vaginal/vulvar cohort. Median overall survival was 21.9 months (95% CI, 15.1 months to not reached) among patients with cervical cancer. Any-grade treatment-related adverse events were reported in 12 of 19 patients (63.2%) in the cervical cohort and all five patients in the vaginal/vulvar cohort; there were no treatment-related deaths. In the cervical cohort, nivolumab treatment generally resulted in stabilization of patient-reported outcomes associated with health status and health-related quality of life. CONCLUSION: The efficacy of nivolumab in patients with recurrent/metastatic cervical and vaginal or vulvar cancers is promising and warrants additional investigation. No new safety signals were identified with nivolumab treatment in this population.

The Dynamic Use of EGFR Mutation Analysis in Cell-Free DNA as a Follow-Up Biomarker during Different Treatment Lines in Non-Small-Cell Lung Cancer Patients.

Epidermal growth factor receptor (EGFR) mutational testing in advanced non-small-cell lung cancer (NSCLC) is usually performed in tumor tissue, although cfDNA (cell-free DNA) could be an alternative. We evaluated EGFR mutations in cfDNA as a complementary tool in patients, who had already known EGFR mutations in tumor tissue and were treated with either EGFR-tyrosine kinase inhibitors (TKIs) or chemotherapy. We obtained plasma samples from 21 advanced NSCLC patients with known EGFR tumor mutations, before and during therapy with EGFR-TKIs and/or chemotherapy. cfDNA was isolated and EGFR mutations were analyzed with the multiple targeted cobas EGFR Mutation Test v2. EGFR mutations were detected at baseline in cfDNA from 57% of patients. The semiquantitative index (SQI) significantly decreased from the baseline (median = 11, IQR = 9.5-13) to the best response (median = 0, IQR = 0-0, p < 0.01), followed by a significant increase at progression (median = 11, IQR = 11-15, p < 0.01) in patients treated with either EGFR-TKIs or chemotherapy. The SQI obtained with the cobas EGFR Mutation Test v2 did not correlate with the concentration in copies/mL determined by droplet digital PCR. Resistance mutation p.T790M was observed at progression in patients with either type of treatment. In conclusion, cfDNA multiple targeted EGFR mutation analysis is useful for treatment monitoring in tissue of EGFR-positive NSCLC patients independently of the drug received.

Combination of pegylated liposomal doxorubicin plus gemcitabine in heavily pretreated metastatic breast cancer patients: Long-term results from a single institution experience.

The combination of Pegylated Liposomal Doxorubicin (PLD) plus Gemcitabine (GEM) has been previously investigated in the treatment of metastatic breast cancer (MBC). PLD is a doxorubicin formulation with prolonged circulation time and better tissue distribution. GEM is a nucleoside analog with nonoverlapping toxicity compared to PLD. The aim of our study was to assess efficacy, toxicity, and long-term outcome of this combination. Patients with heavily treated MBC were retrospectively analyzed. Chemotherapy consisted of PLD 25 mg/m2 and GEM 800 mg/m2 day 1, on a three-week schedule. Cardiac function was evaluated baseline and during treatment. Radiological response was graded according to RECIST criteria v1.1. Toxicity was scored according to CTCAE v4.0. Progression-free survival (PFS) and overall survival (OS) were evaluated. From 2001 to 2014, 122 pts were included. Median age was 55 (range: 28-84). Median previous treatment schedules in the metastatic scenario were 3 (range: 1-15). Most patients received prior anthracyclines (85%). Median number of metastatic sites was 2 (range: 1-7). Median number of cycles delivered was 5 (range: 1-36). Overall response rate was 31% (5% complete responses; 26% partial responses). Stable and progressive diseases were observed in 32% and 26% of patients. Grade ≥3 neutropenia was observed in 29 patients (24%). Grade ≥3 hand-foot syndrome was detected in 17 patients (14%), mostly since cycle 3 (88%). Median cumulative PLD dose was 125 mg/m2 . At a median follow-up of 101 months, median PFS and OS were 7 and 22 months, respectively. PLD-GEM combination achieves remarkable long-term outcomes with an acceptable toxicity profile in patients with MBC.

Functional expression of CD137 (4-1BB) on T helper follicular cells.

CD137 (4-1BB) is a surface protein initially discovered to mark activated T lymphocytes. However, its broader expression pattern also encompasses activated NK cells, B cells and myeloid cells, including mature dendritic cells. In this study, we have immunostained for CD137 on paraffin-embedded lymphoid tissues including tonsils, lymph nodes, ectopic tertiary lymphoid tissue in Hashimoto thyroiditis and cancer. Surprisingly, immunostaining mainly decorated intrafollicular lymphocytes in the tissues analyzed, with only scattered staining in interfollicular areas. Moreover, pathologic lymphoid follicles in follicular lymphoma and tertiary lymphoid tissue associated with non-small cell lung cancer showed a similar pattern of immunostaining. Multispectral fluorescence cytometry demonstrated that CD137 expression was restricted to CD4+ CXCR5+ follicular T helper lymphocytes (TFH cells) in tonsils and lymph nodes. Short-term culture of lymph node cell suspensions in the presence of either an agonistic anti-CD137 monoclonal antibody (mAb) or CD137-ligand stimulated the functional upregulation of TFH cells in 3 out of 6 cases, as indicated by CD40L surface expression and cytokine production. As a consequence, immunostimulatory monoclonal antibodies targeting CD137 (such as urelumab and PF-05082566) should be expected to primarily act on this lymphocyte subset, thus modifying ongoing humoral immune responses in patients with autoimmune disease and cancer.

Factors influencing the use of thromboprophylaxis in cancer outpatients in clinical practice: A prospective study.

INTRODUCTION: Current clinical practice guidelines do not recommend routine pharmacological thromboprophylaxis in cancer outpatients receiving chemotherapy. However, a high proportion of cancer-associated venous thromboembolism (VTE) events occur in this setting. There are scarce data on the use of thromboprophylaxis in ambulatory cancer patients in real clinical practice. MATERIAL AND METHODS: We conducted a single-center prospective study aimed to evaluate the use and factors influencing pharmacological prophylaxis in consecutive cancer patients receiving ambulatory chemotherapy. Patients were followed for 90 days after inclusion. RESULTS: A total of 1108 patients were included. According to the Khorana score, 45.8% patients were classified as low-risk, 47.4% intermediate-risk and 6.8% as high-risk. Outpatient pharmacological prophylaxis was administered at any time during follow-up to 157 patients (14.2%) with a median duration of 42 days (range 1-90). Main factors influencing thromboprophylaxis were: previous history of VTE (odds ratio [OR], 19.11; 95% CI, 9.61-37.98), intercurrent hospitalization (OR, 5.40; 95% CI, 3.57-8.16), and gastrointestinal or gynecologic cancer (OR, 1.76; 95% CI, 1.11-2.80 and OR, 2.34; 95% CI, 1.05-5.26, respectively). During follow-up 58 (5.2%) VTE events were observed. Independent predictors of VTE were the site of malignancy (OR, 3.04; 95%CI, 1.20-7.71 and OR, 2.47; 95%CI, 1.21-5.01 for pancreas and lung cancer, respectively) and previous VTE (OR, 4.23; 95%CI, 1.26-14.27). Outpatient prophylaxis was associated with a lower risk of VTE during follow-up (OR, 0.30; 95%CI, 0.10-0.95). CONCLUSIONS: Although the type of malignancy appears as the most relevant variable for decision-making, additional efforts are required to identify patients at particular high thrombosis risk.

Serum interleukin-8 reflects tumor burden and treatment response across malignancies of multiple tissue origins.

PURPOSE: Interleukin-8 (IL8) is a chemokine produced by malignant cells of multiple cancer types. It exerts various functions in shaping protumoral vascularization and inflammation/immunity. We evaluated sequential levels of serum IL8 in preclinical tumor models and in patients to assess its ability to estimate tumor burden. EXPERIMENTAL DESIGN: IL8 levels were monitored by sandwich ELISAs in cultured tumor cells supernatants, tumor-xenografted mice serum, and in samples from 126 patients with cancer. We correlated IL8 serum levels with baseline tumor burden and with treatment-induced changes in tumor burden, as well as with prognosis. RESULTS: IL8 concentrations correlated with the number of IL8-producing tumor cells in culture. In xenografted neoplasms, IL8 serum levels rapidly dropped after surgical excision, indicating an accurate correlation with tumor burden. In patients with melanoma (n = 16), renal cell carcinoma (RCC; n = 23), non-small cell lung cancer (NSCLC; n = 21), or hepatocellular carcinoma (HCC; n = 30), serum IL8 concentrations correlated with tumor burden and stage, survival (melanoma, n = 16; RCC, n = 23; HCC, n = 33), and objective responses to therapy, including those to BRAF inhibitors (melanoma, n = 16) and immunomodulatory monoclonal antibodies (melanoma, n = 8). IL8 concentrations in urine (n = 18) were mainly elevated in tumors with direct contact with the urinary tract. CONCLUSIONS: IL8 levels correlate with tumor burden in preclinical models and in patients with cancer. IL8 is a potentially useful biomarker to monitor changes in tumor burden following anticancer therapy, and has prognostic significance.

CD8 T cell priming in the presence of IFN-α renders CTLs with improved responsiveness to homeostatic cytokines and recall antigens: important traits for adoptive T cell therapy.

Previous mouse and human studies have demonstrated that direct IFN-α/ß signaling on naive CD8 T cells is critical to support their expansion and acquisition of effector functions. In this study, we show that human naive CD8 T cells primed in the presence of IFN-α possess a heightened ability to respond to homeostatic cytokines and to secondary Ag stimulation, but rather than differentiating to effector or memory CTLs, they preserve nature-like phenotypic features. These are qualities associated with greater efficacy in adoptive immunotherapy. In a mouse model of adoptive transfer, CD8 T cells primed in the presence of IFN-α are able to persist and to mediate a robust recall response even after a long period of naturally driven homeostatic maintenance. The long-lasting persistence of IFN-α-primed CD8 T cells is favored by their enhanced responsiveness to IL-15 and IL-7, as demonstrated in IL-15(-/-) and IL-7(-/-) recipient mice. In humans, exposure to IFN-α during in vitro priming of naive HLA-A2(+) CD8 T cells with autologous dendritic cells loaded with MART1(26-35) peptide renders CD8 T cells with an improved capacity to respond to homeostatic cytokines and to specifically lyse MART1-expressing melanoma cells. Furthermore, in a mouse model of melanoma, adoptive transfer of tumor-specific CD8 T cells primed ex vivo in the presence of IFN-α exhibits an improved ability to contain tumor progression. Therefore, exposure to IFN-α during priming of naive CD8 T cells imprints decisive information on the expanded cells that can be exploited to improve the efficacy of adoptive T cell therapy.

Isolated dysphagia due to paraneoplastic myasthenic syndrome with anti-P/Q-type voltage-gated calcium-channel and anti-acetylcholine receptor antibodies.

Dysphagia is a common symptom in neuromuscular junction disorders, but it rarely occurs in isolation or is the presenting feature. We describe a patient presenting with isolated dysphagia to liquids. Electrophysiological studies, such as repetitive nerve stimulation and single-fiber electromyography, were normal. Serum anti-P/Q-type voltage-gated calcium-channel (anti-P/Q-type VGCC) and anti-acetylcholine receptor (AChR ab) antibodies were above the normal range. A computed tomography scan showed a mediastinal mass corresponding to a thymic carcinoma. After chemotherapy, surgical removal of the thymic carcinoma and radiotherapy, the patient no longer complained of dysphagia, AChR ab titers were reduced and anti-P/Q-type VGCC antibodies became negative. To the best of our knowledge, no previous reports of a paraneoplastic myasthenic syndrome related to thymic carcinoma with both anti-P/Q-type VGCC and AChR antibodies have been described.

The oncoprotein SF2/ASF promotes non-small cell lung cancer survival by enhancing survivin expression.

PURPOSE: SF2/ASF is a splicing factor recently described as an oncoprotein. In the present work, we examined the role of SF2/ASF in human non-small cell lung cancer (NSCLC) and analyzed the molecular mechanisms involved in SF2/ASF-related carcinogenesis. EXPERIMENTAL DESIGN: SF2/ASF protein levels were analyzed in 81 NSCLC patients by immunohistochemistry. SF2/ASF downregulation cellular models were generated using small interfering RNAs, and the effects on proliferation and apoptosis were evaluated. Survivin and SF2/ASF expression in lung tumors was analyzed by Western blot and immunohistochemistry. Survival curves and log-rank test were used to identify the association between the expression of the proteins and time to progression. RESULTS: Overexpression of SF2/ASF was found in most human primary NSCLC tumors. In vitro downregulation of SF2/ASF induced apoptosis in NSCLC cell lines. This effect was associated with a reduction in the expression of survivin, an antiapoptotic protein widely upregulated in cancer. In fact, SF2/ASF specifically bound survivin mRNA and enhanced its translation, via a mammalian target of rapamycin complex 1 (mTORC1) pathway-dependent mechanism, through the phosphorylation and inactivation of the translational repressor 4E-BP1. Moreover, SF2/ASF promoted the stability of survivin mRNA. A strong correlation was observed between the expression of SF2/ASF and survivin in tumor biopsies from NSCLC patients, supporting the concept that survivin expression levels are controlled by SF2/ASF. Furthermore, combined expression of these proteins was associated with prognosis. CONCLUSION: This study provides novel data on the mTORC1- and survivin-dependent mechanisms of SF2/ASF-related carcinogenic potential, and shows that SF2/ASF and survivin expression is involved in NSCLC progression.

Complement activation mediates cetuximab inhibition of non-small cell lung cancer tumor growth in vivo.

BACKGROUND: Cetuximab, an antibody targeting the epidermal growth factor receptor (EGFR), increases survival in patients with advanced EGFR-positive non-small cell lung cancer when administrated in combination with chemotherapy. In this study, we investigated the role of complement activation in the antitumor mechanism of this therapeutic drug. RESULTS: EGFR-expressing lung cancer cell lines were able to bind cetuximab and initiate complement activation by the classical pathway, irrespective of the mutational status of EGFR. This activation led to deposition of complement components and increase in complement-mediated cell death. The influence of complement activation on the activity of cetuximab in vivo was evaluated in xenografts of A549 lung cancer cells on nude mice. A549 cells express wild-type EGFR and have a KRAS mutation. Cetuximab activity against A549 xenografts was highly dependent on complement activation, since complement depletion completely abrogated the antitumor efficacy of cetuximab. Moreover, cetuximab activity was significantly higher on A549 cells in which a complement inhibitor, factor H, was genetically downregulated. CONCLUSIONS: We demonstrate for the first time that the in vivo antitumor activity of cetuximab can be associated with a complement-mediated immune response. These results may have important implications for the development of new cetuximab-based therapeutic strategies and for the identification of markers that predict clinical response.

Development of a novel splice array platform and its application in the identification of alternative splice variants in lung cancer.

BACKGROUND: Microarrays strategies, which allow for the characterization of thousands of alternative splice forms in a single test, can be applied to identify differential alternative splicing events. In this study, a novel splice array approach was developed, including the design of a high-density oligonucleotide array, a labeling procedure, and an algorithm to identify splice events. RESULTS: The array consisted of exon probes and thermodynamically balanced junction probes. Suboptimal probes were tagged and considered in the final analysis. An unbiased labeling protocol was developed using random primers. The algorithm used to distinguish changes in expression from changes in splicing was calibrated using internal non-spliced control sequences. The performance of this splice array was validated with artificial constructs for CDC6, VEGF, and PCBP4 isoforms. The platform was then applied to the analysis of differential splice forms in lung cancer samples compared to matched normal lung tissue. Overexpression of splice isoforms was identified for genes encoding CEACAM1, FHL-1, MLPH, and SUSD2. None of these splicing isoforms had been previously associated with lung cancer. CONCLUSIONS: This methodology enables the detection of alternative splicing events in complex biological samples, providing a powerful tool to identify novel diagnostic and prognostic biomarkers for cancer and other pathologies.

Toxic epidermal necrolysis related to pemetrexed and carboplatin with vitamin B12 and folic acid supplementation for advanced non-small cell lung cancer.

BACKGROUND: Pemetrexed is a multitargeted antifolate initially approved as a single agent for the second-line treatment of locally advanced or metastatic non-small cell lung cancer and more recently in the first-line setting combined with cisplatin. The combination of pemetrexed with carboplatin has been tested in several phase II clinical trials showing interesting antitumour activity with mild toxicity. Supplementation with folic acid and vitamin B12 during treatment with pemetrexed is recommended to reduce potential haematological and gastrointestinal adverse events. CASE REPORT: A patient experienced cutaneous lesions including widespread erythema, epidermal detachment, and skin denudation, associated with deterioration of his general condition after the second cycle of this chemotherapy combination, which was clinically and histologically compatible with toxic epidermal necrolysis (Lyell's syndrome). Treatment with systemic steroids, antihistamines, and antibiotics led to resolution of the skin lesions and improvement of his general condition. CONCLUSION: To our knowledge, this is the second case reported in the literature of this type of suspected adverse drug reaction associated with a pemetrexed-based chemotherapy combination.

Fibrosing cholestatic hepatitis following cytotoxic chemotherapy for small-cell lung cancer.

Fibrosing cholestatic hepatitis (FCH) is a variant of viral hepatitis reported in hepatitis B virus or hepatitis C virus infected liver, renal or bone transplantation recipients and in leukemia and lymphoma patients after conventional cytotoxic chemotherapy. FCH constitutes a well-described form of fulminant hepatitis having extensive fibrosis and severe cholestasis as its most characteristic pathological findings. Here, we report a case of a 49-year-old patient diagnosed with small-cell lung cancer who developed this condition following conventional chemotherapy-induced immunosuppression. This is the first reported case in the literature of FCH after conventional chemotherapy for a solid tumor. In addition to a detailed report of the case, a physiopathological examination of this potentially life-threatening condition and its treatment options are discussed.

Randomized crossover pharmacokinetic evaluation of subcutaneous versus intravenous granisetron in cancer patients treated with platinum-based chemotherapy.

BACKGROUND: 5-HT3-receptor antagonists are one of the mainstays of antiemetic treatment, and they are administered either i.v. or orally. Nevertheless, sometimes neither administration route is feasible, such as in patients unable to admit oral intake managed in an outpatient setting. Our objective was to evaluate the bioavailability of s.c. granisetron. PATIENTS AND METHODS: Patients receiving platinum-based chemotherapy were randomized to receive 3 mg of granisetron either s.c. or i.v. in a crossover manner during two cycles. Blood and urine samples were collected after each cycle. Pharmacokinetic parameters observed with each administration route were compared by analysis of variance. RESULTS: From May to November 2005, 31 patients were included and 25 were evaluable. Subcutaneous granisetron resulted in a 27% higher area under the concentration-time curve for 0-12 hours (AUC(0-12h)) and higher levels at 12 hours, with similar values for AUC(0-24h). The maximum concentration was lower with the s.c. than with the i.v. route and was observed 30 minutes following s.c. administration. CONCLUSION: Granisetron administered s.c. achieves complete bioavailability. This is the first study that shows that s.c. granisetron might be a valid alternative to i.v. delivery. Further trials to confirm clinical equivalence are warranted. This new route of administration might be especially relevant for outpatient management of emesis in cancer patients.

Mitogen-activated protein kinase phosphatase-1 is overexpressed in non-small cell lung cancer and is an independent predictor of outcome in patients.

PURPOSE: An increase in the activity of the mitogen-activated protein kinases (MAPKs) has been correlated with a more malignant phenotype in several tumor models in vitro and in vivo. A key regulatory mechanism of the MAPKs [extracellular signal-regulated kinase (ERK); c-jun NH(2)-terminal kinase (JNK); and p38] is the dual specificity phosphatase CL100, also called MAPK phosphatase-1 (MKP-1). This study was designed to examine the involvement of CL100/MKP-1 and stress-related MAPKs in lung cancer. EXPERIMENTAL DESIGN: We assessed the expression of CL100/MKP-1 and the activation of the MAPKs in a panel of 18 human cell lines [1 primary normal bronchial epithelium, 8 non-small cell lung cancer (NSCLC), 7 small cell lung cancer (SCLC), and 2 carcinoids] and in 108 NSCLC surgical specimens. RESULTS: In the cell lines, CL100/MKP-1 expression was substantially higher in NSCLC than in SCLC. P-ERK, P-JNK, and P-p38 were activated in SCLC and NSCLC, but the degree of their activation was variable. Immunohistochemistry in NSCLC resection specimens showed high levels of CL100/MKP-1 and activation of the three MAPK compared with normal lung. In univariate analysis, no relationship was found among CL100/MKP-1 expression and P-ERK, P-JNK, or P-p38. Interestingly, high CL100/MKP-1 expression levels independently predicted improved survival in multivariate analysis. JNK activation associated with T(1-2) and early stage, whereas ERK activation correlated with late stages and higher T and N. Neither JNK nor ERK activation were independent prognostic factors when studied for patient survival. CONCLUSIONS: Our data indicate the relevance of MAPKs and CL100/MKP-1 in lung cancer and point at CL100/MKP-1 as a potential positive prognostic factor in NSCLC. Finally, our study supports the search of new molecular targets for lung cancer therapy within the MAPK signaling pathway.