Profile of soluble factors in pleural effusions predict prognosis in mesothelioma.

BACKGROUND: Pleural mesothelioma is a deadly asbestos induced cancer. Less than 10% of mesothelioma patients survive 5 years post diagnosis. However survival can range from a few months to a number of years. Accurate prediction of survival is important for patients to plan for their remaining life, and for clinicians to determine appropriate therapy. One unusual feature of mesothelioma is that patients frequently present with tumor-associated pleural effusions early in the course of the disease. OBJECTIVE: To study whether cells and molecules present in pleural effusions provide prognostic information for mesothelioma. METHODS: We profiled the cellular constituents and concentrations of 40 cytokines, chemokines and cellular factors (collectively "soluble factors") involved in inflammatory and immune signalling pathways in pleural effusion samples from 50 mesothelioma patients.Associations with survival were evaluated by Cox proportional hazards regression methods. Results for the two soluble factors most significantly and independently associated with survival were validated in an independent set of samples (n= 51) using a separate assay system. RESULTS: Survival analysis revealed that IL8, IL2Ra (CD25) and PF4 were independent determinants of a more negative prognosis in mesothelioma patients, independent of other known prognostic factors. Lipocalin2 and IL4 were associated with better prognosis. CONCLUSIONS: This study demonstrates that pleural effusions rich in a range of soluble factors are associated with poor prognosis. These findings will enhance our ability to prognosticate outcomes in mesothelioma patients.

Neo-antigen specific T cell responses indicate the presence of metastases before imaging.

Non-small cell lung cancer (NSCLC) causes 19% of all Australian cancer deaths, with a 5-year survival post-resection of around 60%. Post-operative recurrence is due to metastases that were undetectable pre-operatively, or growth of microscopic locoregional residual disease. However, post-operative imaging modalities typically only detect more advanced tumours; where PET-CT has a detection limit of 6-7 mm. Detection of small deposits of lung metastatic disease is of importance in order to facilitate early and potentially more effective treatment. In this study, in a murine model of lung metastatic disease, we explore whether neo-antigen specific T cells are a sensitive marker for the detection of lung cancer after primary tumour resection. We determine lung metastatic disease by histology, and then compare detection by PET-CT and neo-antigen specific T cell frequency. Detection of lung metastatic disease within the histology positive group by PET-CT and neo-antigen specific T cell frequency were 22.9% and 92.2%, respectively. Notably, neo-antigen specific T cells in the lung draining lymph node were indicative of metastatic disease (82.8 ± 12.9 spots/105 cells; mean ± SE), compared to healthy lung control (28.5 ± 8.6 spots/105 cells; mean ± SE). Potentially, monitoring tumour neo-antigen specific T cell profiles is a highly sensitive method for determining disease recurrence.

A phase 1b clinical trial of the CD40-activating antibody CP-870,893 in combination with cisplatin and pemetrexed in malignant pleural mesothelioma.

BACKGROUND: Data from murine models suggest that CD40 activation may synergize with cytotoxic chemotherapy. We aimed to determine the maximum tolerated dose (MTD) and toxicity profile and to explore immunological biomarkers of the CD40-activating antibody CP-870,893 with cisplatin and pemetrexed in patients with malignant pleural mesothelioma (MPM). PATIENTS AND METHODS: Eligible patients had confirmed MPM, ECOG performance status 0-1, and measurable disease. Patients received cisplatin 75 mg/m(2) and pemetrexed 500 mg/m(2) on day 1 and CP-870,893 on day 8 of a 21-day cycle for maximum 6 cycles with up to 6 subsequent cycles single-agent CP-870,893. Immune cell subset changes were examined weekly by flow cytometry. RESULTS: Fifteen patients were treated at three dose levels. The MTD of CP-870,893 was 0.15 mg/kg, and was exceeded at 0.2 mg/kg with one grade 4 splenic infarction and one grade 3 confusion and hyponatraemia. Cytokine release syndrome (CRS) occurred in most patients (80%) following CP-870,893. Haematological toxicities were consistent with cisplatin and pemetrexed chemotherapy. Six partial responses (40%) and 9 stable disease (53%) as best response were observed. The median overall survival was 16.5 months; the median progression-free survival was 6.3 months. Three patients survived beyond 30 months. CD19+ B cells decreased over 6 cycles of chemoimmunotherapy (P < 0.001) with a concomitant increase in the proportion of CD27+ memory B cells (P < 0.001) and activated CD86+CD27+ memory B cells (P < 0.001), as an immunopharmacodynamic marker of CD40 activation. CONCLUSIONS: CP-870,893 with cisplatin and pemetrexed is safe and tolerable at 0.15 mg/kg, although most patients experience CRS. While objective response rates are similar to chemotherapy alone, three patients achieved long-term survival. AUSTRALIA NEW ZEALAND CLINICAL TRIALS REGISTRY NUMBER: ACTRN12609000294257.

Harnessing the immune response to treat cancer.

It is well established that the immune system has the capacity to attack malignant cells. During malignant transformation cells acquire numerous molecular and biochemical changes that render them potentially vulnerable to immune cells. Yet it is self-evident that a growing tumour has managed to evade these host defence mechanisms. The exact ways in which the immune system interacts with tumour cells and how cancers are able to escape immunological eradication have only recently started to be fully elucidated. Understanding the relationship between the tumour and the anti-tumour immune response and how this can be altered with conventional treatments and immune-targeted therapies is crucial to developing new treatments for patients with cancer. In this review, focusing on the anti-tumour T-cell response, we summarize our understanding of how tumours, cancer treatments and the immune system interact, how tumours evade the immune response and how this process could be manipulated for the benefit of patients with cancer.

Local effector failure in mesothelioma is not mediated by CD4+ CD25+ T-regulator cells.

The aim of the present study was to define the point at which mesothelioma T-cell responses fail in order to design better immunotherapies. A murine model of mesothelioma was used which was established with asbestos. Inoculation of tumour cells into syngeneic mice results in progressing tumours with similar histopathology to human mesothelioma. The tumour cells secrete a marker tumour antigen similar to secreted tumour-associated products, such as mesothelin. The mesothelioma microenvironment contains stromal elements including dendritic cells, effector CD8(+) and CD4(+) T-cells, and CD4(+) T-regulatory (Tregs) cells, all of which are activated in situ, implying chronic inflammation. Tumour antigens are rapidly transported to draining lymph nodes wherein tumour-specific T-cell responses are generated. Despite the generation of potent CD8(+) cytotoxic lymphocyte in lymphoid organs, those that infiltrate tumours cannot restrain tumour growth suggesting local suppression. Splenic Tregs did not suppress protective responses in adoptive transfer experiments suggesting that systemic Tregs play little role in regulating anti-mesothelioma immune responses. Finally, removal of CD25(+) Tregs from the tumour site and lymphoid organs did not alter tumour growth with or without interleukin (IL)-2 or IL-21 immunotherapy. Tregs are not potent regulators of anti-mesothelioma immunity and targeting these cells may not improve results.

Overexpression and altered glycosylation of MUC1 in malignant mesothelioma.

Current interest in the MUC1/EMA mucin relates to its role in malignancy, and its potential as a therapeutic target. MUC1/EMA expression has been observed in the majority of epithelioid mesotheliomas. However, little is known of the characteristics of MUC1/EMA in mesothelioma. Herein, we studied the cell surface and soluble expression of the MUC1/EMA glycoprotein, and determined the mRNA and genomic expression profiles in mesothelioma. We found that the anti-MUC1 antibody, E29, was the most diagnostically useful of seven antibody clones examined with a sensitivity of 84% (16 out of 19 cases) and no false positive results. MUC1 mRNA expression was significantly higher in mesothelioma samples than in benign mesothelial cells. No amplification of the MUC1 gene was observed by FISH. Seven of 9 mesothelioma samples expressed MUC1-secreted mRNA isoform in addition to the archetypal MUC1/transmembrane form. CA15.3 (soluble MUC1) levels were significantly higher in the serum of mesothelioma patients than in healthy controls but were not significantly different to levels in patients with benign asbestos-related disease. CA15-3 in effusions could differentiate malignant from benign effusions but were not specific for mesothelioma. Thus, as in other cancers, alterations in MUC1 biology occur in mesothelioma and these results suggest that specific MUC1 characteristics may be useful for mesothelioma diagnosis and should also be investigated as a potential therapeutic target.

Decoding dangerous death: how cytotoxic chemotherapy invokes inflammation, immunity or nothing at all.

Chemotherapy and immunotherapy can be either synergistic or antagonistic modalities in the treatment of cancer. Cytotoxic chemotherapy not only affects the tumor but also targets dividing lymphocytes, the very cells that are required to develop an immune response. For this reason, chemo- and immunotherapy have been seen as antagonistic. However, cell death can be immunogenic and the way in which chemotherapeutic drug kills a tumor cell is likely to be an important determinant of how that dying cell interacts with the immune system and whether the interaction will lead to an immune response. When a cell dies as the result of infection, the immune system responds rapidly and the system of Toll-like receptors (TLR) plays a key role in this process. In this review, we will briefly summarize the intracellular signaling pathways that link TLR ligation with immune activation and we will address the questions where and how TLRs recognize their targets.

Gene therapy for malignant mesothelioma: beyond the infant years.

Mesothelioma may be particularly well suited for gene therapy treatment owing to its accessibility, allowing both intrapleural and intratumoral gene delivery. At least four gene therapy trials have been carried out in mesothelioma patients, using different vector systems (adenovirus, vaccinia virus, irradiated tumor cells), and different transgenes (herpes simplex virus thymidine kinase (HSVtk) combined with ganciclovir, IL-2, IFN-beta). Although small in scale, these trials have given an inkling of hope for therapeutic efficacy. However, it is clear that gene therapy protocols need to be optimized further. This paper will review progress made in (i) vector development, (ii) defining optimal transgenes, and (iii) gene delivery. Adenoviruses are the most commonly used vectors for gene therapy, and are continuously being improved. With respect to the nature of the transgenes, five categories can be distinguished: (i) 'suicide' or sensitivity genes (e.g., HSVtk), (ii) cytokines and other immune modulators, (iii) replacements for mutant tumor suppressor genes (e.g., p53), (iv) antiangiogenic proteins and (v) tumor antigens. It seems clear that expression of a single transgene is unlikely to be sufficient to eradicate a tumor, such as mesothelioma, that is diagnosed late in disease progression. Hence, multimodality therapy, including conventional therapy (chemo- and radiotherapy, surgery) with one or more transgenes has a higher chance of success.

A multicentre phase II study of cisplatin and gemcitabine for malignant mesothelioma.

Our previous phase II study of cisplatin and gemcitabine in malignant mesothelioma showed a 47.6% (95% CI 26.2-69.0%) response rate with symptom improvement in responding patients. Here we confirm these findings in a multicentre setting, and assess the effect of this treatment on quality of life and pulmonary function. Fifty-three patients with pleural malignant mesothelioma received cisplatin 100 mg m(-2) i.v. day 1 and gemcitabine 1000 mg m(-2) i.v. days 1, 8, and 15 of a 28 day cycle for a maximum of six cycles. Quality of life and pulmonary function were assessed at each cycle. The best response achieved in 52 assessable patients was: partial response, 17 (33%, 95% CI 20-46%); stable disease, 31 (60%); and progressive disease, four (8%). The median time to disease progression was 6.4 months, median survival from start of treatment 11.2 months, and median survival from diagnosis 17.3 months. Vital capacity and global quality of life remained stable in all patients and improved significantly in responding patients. Major toxicities were haematological, limiting the mean relative dose intensity of gemcitabine to 75%. This schedule of cisplatin and gemcitabine is active in malignant mesothelioma in a multicentre setting. Investigation of alternative scheduling is needed to decrease haematological toxicity and increase the relative dose intensity of gemcitabine whilst maintaining response rate and quality of life.