Final results of DIADEM, a phase II study to investigate the efficacy and safety of durvalumab in advanced pretreated malignant pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a cancer with a high mortality rate and few therapeutic options. After platinum-pemetrexed combination, no further promising drug seems to be effective. Immune checkpoint inhibitors may have some activity in pretreated patients and no data are available in this population about durvalumab. MATERIALS AND METHODS: DIADEM was a multicenter, open-label, single-arm, phase II trial aimed at evaluating the efficacy and safety of durvalumab. Patients with locally advanced/metastatic MPM who progressed after platinum-pemetrexed chemotherapy were enrolled to receive durvalumab (1500 mg, intravenously Q4W) for 12 months or until evidence of disease progression or unacceptable toxicity. The primary endpoint was the proportion of patients alive and free from progression at 16 weeks (PFS16wks) calculated from treatment initiation. Secondary endpoints were progression-free survival, overall survival, overall response rate, and safety. RESULTS: Sixty-nine patients with a median age of 69 years (range 44-82 years) were enrolled; 62 patients (89.9%) had epithelioid histotype. As first-line treatment, all patients received platinum derivatives-pemetrexed combination (60.9% with carboplatin and 39.1% with cisplatin). As of March 2021, the median follow-up was 9.2 months (interquartile range 5.2-11.1 months). Six patients (8.7%) completed the 12-month treatment; 60 patients discontinued, of whom 42 for progressive disease, and 4 died. Seventeen patients (28.3%; 95% confidence interval 17.5% to 41.4%) were alive or free from progression at 16 weeks. Eleven patients (18.6%) had a grade 3 or 4 treatment-related adverse event (AE), and one (1.4%) had a grade ≥3 immune-related, treatment-related AE. There was one drug-related death. CONCLUSION: Durvalumab alone in pretreated non-selected MPM did not reach a meaningful clinical activity, showing any new major safety issue signals.

Long-term benefit of lurbinectedin as palliative chemotherapy in progressive malignant pleural mesothelioma (MPM): final efficacy and translational data of the SAKK 17/16 study.

BACKGROUND: The SAKK 17/16 study showed promising efficacy data with lurbinectedin as second- or third-line palliative therapy in malignant pleural mesothelioma. Here, we evaluated long-term outcome and analyzed the impact of lurbinectedin monotherapy on the tumor microenvironment at the cellular and molecular level to predict outcomes. MATERIAL AND METHODS: Forty-two patients were treated with lurbinectedin in this single-arm study. Twenty-nine samples were available at baseline, and seven additional matched samples at day one of cycle two of treatment. Survival curves and rates between groups were compared using the log-rank test and Kaplan-Meier method. Statistical significance was set at P value <0.05. RESULTS: Updated median overall survival (OS) was slightly increased to 11.5 months [95% confidence interval (CI) 8.8-13.8 months]. Thirty-six patients (85%) had died. The OS rate at 12 and 18 months was 47% (95% CI 32.1% to 61.6%) and 31% (95% CI 17.8% to 45.0%), respectively. Median progression-free survival was 4.1 months (95% CI 2.6-5.5 months). No new safety signals were observed. Patients with lower frequencies of regulatory T cells, as well as lower tumor-associated macrophages (TAMs) at baseline, had a better OS. Comparing matched biopsies, a decrease of M2 macrophages was observed in five out of seven patients after exposure to lurbinectedin, and two out of four patients showed increased CD8+ T-cell infiltrates in tumor. DISCUSSION: Lurbinectedin continues to be active in patients with progressing malignant pleural mesothelioma. According to our very small sample size, we hypothesize that baseline TAMs and regulatory T cells are associated with survival. Lurbinectedin seems to inhibit conversion of TAMs to M2 phenotype in humans.

Treating disease progression with osimertinib in EGFR-mutated non-small-cell lung cancer: novel targeted agents and combination strategies.

A precision medicine approach has been successfully applied in medical oncology for the treatment of non-small-cell lung cancer (NSCLC) through the identification of targetable driver molecular aberrations; activating mutations of epidermal growth factor receptor (EGFR) are the most common. Osimertinib, a third-generation, wild-type sparing, irreversible EGFR tyrosine kinase inhibitor (TKI), originally showed a striking activity after progression to first- and second-generation EGFR-TKIs when T790M resistance mutation was identified. Thereafter, upfront use of osimertinib became the standard of care based on overall survival benefit over first-generation TKIs erlotinib and gefitinib as reported in the FLAURA trial. For patients progressing on osimertinib, identification of resistance mechanisms is crucial to develop novel targeted therapeutic approaches. Moreover, innovative drugs or combination therapies are being developed for cases in which a specific resistance mechanism is not identifiable. In this review, the post-osimertinib treatment options for EGFR-mutated NSCLC are analyzed, with an outlook to ongoing clinical trials. An algorithm to guide clinicians in managing progression on osimertinib is proposed.

Metronomic oral vinorelbine in previously untreated advanced non-small-cell lung cancer patients unfit for platinum-based chemotherapy: results of the randomized phase II Tempo Lung trial.

BACKGROUND: To assess the efficacy and safety of a metronomic schedule of oral vinorelbine (mVNR) in advanced non-small-cell lung cancer (NSCLC) in patients unfit for platinum-based combination chemotherapy. PATIENTS AND METHODS: This was a multicenter, prospective, randomized, open-label phase II study in treatment-naive patients with TNM stage IIIB/IV NSCLC. Patients received mVNR at a fixed dose of 50 mg × 3 or standard schedule 60-80 mg/m2 weekly until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS) without grade 4 toxicity (G4PFS; NCI-CTC v4). Main secondary objectives were safety, disease control rate (DCR) without grade 4 toxicity (G4DCR), DCR, PFS, overall survival (OS) and quality of life (QoL). RESULTS: A total of 167 patients were included, 83 and 84 patients in the mVNR and standard arms, respectively. The median G4PFS was 4.0 months [95% confidence interval (CI): 2.6-4.3] and 2.2 months (95% CI: 1.5-2.9), hazard ration (HR) = 0.63 (95% CI: 0.45-0.88), P = 0.0068 in favor of metronomic arm; G4DCR was 45.8% and 26.8% in the mVNR and standard arms, respectively. Grade 3-4 treatment-related adverse events were less frequent in the mVNR arm (25.3% versus 54.4%) mainly owing to a reduction in all grades (15.7% versus 51.9%) and grade 3-4 neutropenia (10.8% versus 42%). PFS was 4.3 (95% CI: 3.3-5.1) and 3.9 months (95% CI: 2.8-5.2) in mVNR and standard arms, respectively. No difference in median OS was observed. QoL was comparable between arms. CONCLUSIONS: Metronomic oral vinorelbine significantly prolonged median G4PFS in advanced NSCLC patients unfit for platinum combinations as first-line treatment. It was associated with a clear reduction in toxicity and may be considered as an important option in this challenging population.

Lurbinectedin as second- or third-line palliative therapy in malignant pleural mesothelioma: an international, multi-centre, single-arm, phase II trial (SAKK 17/16).

BACKGROUND: Systemic second- and third-line therapies for malignant pleural mesothelioma (MPM) result in a median progression-free survival (mPFS) of <2 months and median overall survival (mOS) of 6-9 months. Lurbinectedin binds to the DNA of the regulatory region while inhibiting tumour-associated macrophage transcription. In early trials, encouraging outcomes occurred in patients (pts) with MPM treated with lurbinectedin. We aimed to generate lurbinectedin efficacy and safety data among pts with progressive MPM. PATIENTS AND METHODS: Pts with progressing MPM treated with first-line platinum-pemetrexed chemotherapy with or without immunotherapy received lurbinectedin monotherapy. Treatment was given intravenously at 3.2 mg/m2 dose every 3 weeks until progression or unacceptable toxicity. Using Simon's two-stage design, the primary endpoint, progression-free survival (PFS) at 12 weeks (PFS12wks), was met if achieved by ≥21 pts (p0 ≤35% versus p1 ≥55%). RESULTS: Forty-two pts from nine centres across Switzerland and Italy were recruited. Histology was epithelioid in 33 cases, sarcomatoid in 5, and biphasic in 4. Overall 10/42 (23.8%) underwent prior immunotherapy and 14/42 (33.3%) had progressed ≤6 months after first-line chemotherapy. At data cut-off PFS12wks was met by 22/42 pts (52.4%; 90% confidence interval (CI): 38.7% to 63.5%; P = 0.015) with an mPFS of 4.1 months and mOS of 11.1 months. The best response was complete and partial remission observed in one patient each and stable disease in 20 pts. The duration of disease control was 6.6 months (95% CI: 5.2-7.4). No significant difference in PFS12wks, mPFS, and mOS was recorded in epithelioid versus non-epithelioid cases and pts with prior immunotherapy versus those without. Similar mPFS but shorter mOS were observed among pts who progressed within ≤6 months after first-line chemotherapy. Lurbinectedin-related grade 3-4 toxicity was seen in 21 pts, mostly being neutropenia (23.8%) and fatigue (16.7%). CONCLUSIONS: The primary efficacy endpoint was reached with acceptable toxicity. Lurbinectedin showed promising activity regardless of histology, prior immunotherapy, or outcome on prior treatment. CLINICALTRIALS. GOV IDENTIFIER: NCT03213301.

Malignant pleural mesothelioma immune microenvironment and checkpoint expression: correlation with clinical-pathological features and intratumor heterogeneity over time.

Background: Tumor immune microenvironment (TME) plays a key role in malignant pleural mesothelioma (MPM) pathogenesis and treatment outcome, supporting a role of immune checkpoint inhibitors as anticancer approach. This study retrospectively investigated TME and programmed death ligand 1 (PD-L1) expression in naïve MPM cases and their change under chemotherapy. Patients and methods: Diagnostic biopsies of MPM patients were collected from four Italian and one Slovenian cancer centers. Pathological assessment of necrosis, inflammation, grading, and mitosis was carried out. Ki-67, PD-L1 expression, and tumor infiltrating lymphocytes were detected by immunohistochemistry. When available, the same paired sample after chemotherapy was analyzed. Pathological features and clinical characteristics were correlated to overall survival. Results: TME and PD-L1 expression were assessed in 93 and 65 chemonaive MPM samples, respectively. Twenty-eight samples have not sufficient tumor tissue for PD-L1 expression. Sarcomatoid/biphasic samples were characterized by higher CD8+ T lymphocytes and PD-L1 expression on tumor cells, while epithelioid showed higher peritumoral CD4+ T and CD20+ B lymphocytes. Higher CD8+ T lymphocytes, CD68+ macrophages, and PD-L1 expression were associated with pathological features of aggressiveness (necrosis, grading, Ki-67). MPM cases characterized by higher CD8+ T-infiltrate showed lower response to chemotherapy and worse survival at univariate analysis. Patients stratification according to a combined score including CD8+ T lymphocytes, necrosis, mitosis, and proliferation index showed median overall survival of 11.3 months compared with 16.4 months in cases with high versus low combined score (P < 0.003). Subgroup exploratory analysis of 15 paired samples before and after chemotherapy showed a significant increase in cytotoxic T lymphocytes in MPM samples and PD-L1 expression in immune cells. Conclusions: TME enriched with cytotoxic T lymphocytes is associated with higher levels of macrophages and PD-L1 expression on tumor cells and with aggressive histopathological features, lower response to chemotherapy and shorter survival. The role of chemotherapy as a tumor immunogenicity inducer should be confirmed in a larger validation set.

Improvement in survival and quality of life with new therapeutic agents in metastatic castration-resistant prostate cancer: comparison among the results.

Androgen deprivation therapy is the mainstay of treatment for men affected by metastatic prostate cancer (PC). Unfortunately, nearly all patient will become resistant to the initial hormonal approach, developing a metastatic castration-resistant prostate cancer (mCRPC). For many years, chemotherapy with docetaxel has been the only established standard of care for men with mCRPC. Recent developments in the knowledge of the disease biology have shown that during the progression to the castrate status PC remains dependent on androgens and androgen receptor (AR) pathway. As a consequence, new agents like abiraterone acetate and enzalutamide have been rapidly developed and approved for clinical use. Other drugs with different mechanisms of action, such as sipuleucel-T, cabazitaxel, and radium-223 have shown to improve overall survival, symptom control and quality of life of mCRPC patients. However, the optimal sequencing and combination of these treatments are not defined yet. Studies on biomarkers for treatment selection, such as AR splice variants, are promising, but the initial data still need prospective validation on large patient series.

Role of chemotherapy in combination with hormonal therapy in first-line treatment of metastatic hormone-sensitive prostate cancer.

Prostate cancer (PC) is a heterogeneous disease, whose growth is driven by androgens and androgen receptors. Androgen deprivation therapy (ADT) is the standard treatment of hormone-naïve metastatic disease. The majority of patients are treated with medical castration with GnRH agonists or antagonists, which usually determines a profound PSA decline and a radiological and clinical benefit. However, essentially all patients experience progression to castration-resistant prostate cancer (CRPC), and overall prognosis remains disappointing. Early targeting of cells that survive hormonal therapy may potentially prevent the development of CRPC. Several trials have explored the use of combination therapy with ADT and chemotherapy, targeting both the androgen dependent and independent cells simultaneously. Docetaxel was administered in combination with ADT to men with hormone-naïve metastatic prostate cancer, in the attempt to improve the duration and quality of patient survival. Three large randomized trials (the GETUG-15, CHAARTED and more recently the STAMPEDE study) have assessed these endpoints, with partially conflicting results. Overall, the results from these trials seem to support the use of early docetaxel combined with ADT in selected hormone-naïve metastatic PC patients. Full publication of the results of all studies, with longer follow-up, and the results of other ongoing trials in this setting will hopefully further define the role and the indications of this therapeutic strategy.

Prognostic factors in elderly patients with malignant pleural mesothelioma: results of a multicenter survey.

BACKGROUND: The incidence of malignant pleural mesothelioma (MPM) in elderly patients is increasing. There are no specific guidelines for their management. METHODS: The clinical records of elderly patients (⩾70 years old) with MPM referred from January 2005 to November 2011 to six Italian Centres were reviewed. Age, gender, histology, International Mesothelioma Interest Group (IMIG) stage, Eastern Cooperative Oncology Group Performance Status (ECOG-PS), Charlson Comorbidity Index (CCI) and treatment modalities were analysed and correlated to overall survival (OS). RESULTS: In total, 241 patients were identified. Charlson Comorbidity Index was ⩾1 in 92 patients (38%). Treatment was multimodality therapy including surgery in 18, chemotherapy alone in 180 (75%) and best supportive care in 43 cases (18%). Chemotherapy was mainly pemetrexed based. Median OS was 11.4 months. Non-epithelioid histology (HR 2.32; 95% CI 1.66-3.23, P<0.001), age ⩾75 years (HR 1.44; 95% CI 1.08-1.93, P=0.014), advanced (III-IV) stage (HR 1.47; 95% CI 1.09-1.98, P=0.011) and CCI⩾1 (HR 1.38; 95% CI 1.02-1.85, P=0.034) were associated to a shorter OS. Treatment with pemetrexed was associated with improved OS (HR 0.40; 95% CI 0.28-0.56, P<0.001). CONCLUSIONS: Non-epithelioid histology, age ⩾75 years, advanced IMIG stage and presence of comorbidities according to CCI were significant prognostic factors in elderly patients with MPM. Treatment with pemetrexed-based chemotherapy was feasible in this setting. Prospective dedicated trials in MPM elderly patients selected according to prognostic factors including comorbidity scales are warranted.

Vinorelbine in pemetrexed-pretreated patients with malignant pleural mesothelioma.

BACKGROUND: Pemetrexed-platinum chemotherapy is the standard first-line treatment of unresectable malignant pleural mesothelioma (MPM). At progression, patients are generally selected to experimental trials, when available, or, in every-day clinical practice, they are offered second-line chemotherapy. The optimal treatment has not yet been defined. The aim of this retrospective, single-center study was to evaluate the activity and toxicity of vinorelbine administered to a consecutive series of pemetrexed-pretreated MPM patients. METHODS: Vinorelbine 25 mg/m(2) was administered intravenously as a single agent on days 1, 8 every three weeks, either as second-line (2L) or further-line (>2L) therapy. Treatment was repeated for a maximum of 6 cycles, until progression, or unacceptable toxicity. RESULTS: Fifty-nine patients were included in this analysis. Vinorelbine was given to 34 patients as 2L, and to 25 as > 2L treatment. The median age was 69 years (range 45-80). Forty-two patients (71.2%) had a good EORTC prognostic score. Partial response was observed in 9 (15.2%) cases, stable disease in 20 (33.9%). The overall disease control rate (DCR) was 49.1%. Median progression-free survival (PFS) and overall survival (OS) were 2.3 and 6.2 months, respectively. ECOG performance status (PS) (HR(0 vs. 1-2) 0.50; 95%CI: 0.3-0.8; p = 0.014) and PFS ≥ 6 months following first-line (FL) chemotherapy (HR(FL-PFS>6 ms vs. <6 ms) 0.50; 95%CI: 0.3-0.9; p = 0.031) were significantly associated to OS in multivariate analysis. No difference was observed in terms of DCR, PFS, and OS in relation to age, histology, sex, line of vinorelbine therapy, or response to FL treatment. Hematological toxicity was acceptable, with grade 3/4 neutropenia occurring in 5 (8.4%) patients, and there were no cases of febrile neutropenia. The main non-hematological toxicities were grade 2 fatigue in 17 (28.8%) and constipation in 7 (11.8%) patients. CONCLUSIONS: Vinorelbine was moderately active in pemetrexed-pretreated MPM patients, with an acceptable toxicity profile, particularly in patients with ECOG-PS0 and FL-PFS ≥ 6 months.

MicroRNAs in non-small cell lung cancer: current status and future therapeutic promises.

A biological characterization of tumor tissue is mandatory in NSCLC patients to identify cases at high risk of recurrence and to drive current targeted therapies such as EGFR and ALK inhibitors. In addition, promising results have been reported on the utility of molecular parameters for the prediction of the efficacy of systemic cytotoxic therapy. MicroRNAs (miRNAs) are small single stranded non-coding RNA molecules, which regulate gene expression at the posttranscriptional level. Growing evidence suggests that miRNAs are expressed aberrantly in many human cancers and that they play a significant role in carcinogenesis and cancer progression. There is increasing evidence that miRNA profiling may become an accurate way to differentiate tumor subtypes, determine prognosis and response to therapy. This review aims to summarize the current literature on this rapidly evolving field.

Phase II study of pemetrexed and carboplatin plus bevacizumab as first-line therapy in malignant pleural mesothelioma.

BACKGROUND: The aim of this open label phase II study (NCT00407459) was to assess the activity of the vascular endothelial growth factor (VEGF) inhibitor bevacizumab combined with pemetrexed and carboplatin in patients with previously untreated, unresectable malignant pleural mesothelioma (MPM). METHODS: Eligible patients received pemetrexed 500 mg m(-2), carboplatin area under the plasma concentration-time curve (AUC) 5 mg ml(-1) per minute and bevacizumab 15 mg kg(-1), administered intravenously every 21 days for six cycles, followed by maintenance bevacizumab. The primary end point of the study was progression-free survival (PFS). A 50% improvement in median PFS in comparison with standard pemetrexed/platinum combinations (from 6 to 9 months) was postulated. RESULTS: Seventy-six patients were evaluable for analysis. A partial response was achieved in 26 cases (34.2%, 95% CI 23.7-46.0%). Forty-four (57.9%, 95% CI 46.0-69.1%) had stable disease. Median PFS and overall survival were 6.9 and 15.3 months, respectively. Haematological and non-haematological toxicities were generally mild; however, some severe adverse events were reported, including grade 3-4 fatigue in 8% and bowel perforation in 4% of patients. Three toxic deaths occurred. CONCLUSION: The primary end point of the trial was not reached. However, due to the limitation of a non-randomised phase II design, further data are needed before drawing any definite conclusion on the role of bevacizumab in MPM.

An overview of neoadjuvant chemotherapy in the multimodality treatment of malignant pleural mesothelioma.

Malignant Pleural Mesothelioma (MPM) is an aggressive tumour with poor prognosis and increasing incidence in industrialized countries because of the previous widespread exposure to asbestos fibres and to the long lag period from time of exposure and the diagnosis of the disease. MPM shows high refractoriety to systemic treatment, single-modality treatment was generally ineffective and did not achieve higher results than supportive care. The incidence of local and distant recurrences after surgery remains high and that was the reason for many centres to perform combined treatments. In the attempt of reducing the incidence of local recurrences, a multimodality approach with surgery followed by adjuvant radiotherapy was explored. Extrapleural pneumonectomy (EPP) allows higher doses of radiotherapy to the whole hemithorax by avoiding pulmonary toxicity and the results of this approach is a significant reduction of loco-regional relapses; although, extrathoracic metastasis represent a major problem in the management of the disease because of the impact on overall survival. The success with surgical resection after neoadjuvant chemotherapy in stage IIIA lung cancer has been the impetus for several groups to apply this strategy in MPM aiming at reducing the incidence of distant relapse after surgery. Platinum-based chemotherapy plus gemcitabine or pemetrexed for 3-4 cycles followed by surgery and postoperative high-dose radiotherapy showed the best results in terms of overall and progression free survival. This review will focus on the main clinical studies and overview the results of different chemotherapy regimens in the neoadjuvant treatment of MPM.

Role of EGFR inhibitors in the treatment of central nervous system metastases from non-small cell lung cancer.

Brain metastases (BM) are a common occurrence in patients with non-small cell lung cancer (NSCLC). Standard therapy options include whole brain radiotherapy and, in selected patients, surgery or stereotactic radiosurgery. The role of systemic treatment is controversial. There is a strong clinical rationale for the use of targeted therapies, because patients often have a poor performance status, and are not candidates for cytotoxic chemotherapy or radiotherapy, yet treatment is required to improve the extra-cranial disease. The efficacy of epidermal growth factor receptor (EGFR) inhibitors in the treatment of patients with BM from NSCLC has been reported mainly in case reports or small retrospective case series, with only a few prospective trials. Current evidence suggests that the use of EGFR tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib should be considered in patients with asymptomatic CNS involvement, when clinical characteristics suggest a high likelihood of response; these characteristics are adenocarcinoma histology, never-smoker status, female gender and East Asian ethnicity. Upfront therapy with EGFR TKIs should be strongly considered in asymptomatic patients harboring activating EGFR mutations. In symptomatic BM, radiotherapy (RT) remains the standard treatment. Based on currently available data, treatment with concurrent RT and EGFR TKIs should be investigated in experimental trials only.

Second-line chemotherapy in malignant pleural mesothelioma: results of a retrospective multicenter survey.

The pemetrexed-cisplatin chemotherapy is standard of care in first-line (FL) treatment of malignant pleural mesothelioma (MPM). The second-line (SL) chemotherapy is considered, but the optimal treatment has not been defined yet. The aim of this study was to evaluate the clinical outcomes of SL-therapy in a series of MPM-patients included in a retrospective multicenter database. Clinical records of MPM-patients who received SL-treatment from 1996 to 2008 were reviewed. Study endpoints were response, overall-survival (OS), and progression-free-survival (PFS) for SL, stratified for patient characteristics, FL-outcomes, and type of SL. Out of 423 patients, 181 with full clinical data were identified. Patients' characteristics: median-age 64 years (range: 36-85); male gender 115 (63.5%); good EORTC-score 109 (60.2%); epithelial histology 135 (74.6%). After FL, 147 (81.2%) patients achieved disease-control (DC) and 45 had a time-to-progression≥12 months (TTP≥12). After SL, 95 patients (52.6%) achieved DC (21 response; 74 stable-disease); median PFS and OS were 4.3 and 8.7 months, respectively. According to multivariate analysis, DC after SL-therapy was significantly related to pemetrexed-based treatment (OR: 2.46; p=0.017) and FL-TTP≥12 (OR: 3.50; p=0.006). PFS was related to younger age (<65 years) (HR: 0.70; p=0.045), ECOG-PS0 (HR: 0.67; p=0.022), and FL-TTP≥12 (HR: 0.45; p<0.001). OS was significantly related to ECOG-PS0 (HR: 0.43; p<0.001) and to FL-TTP≥12 (HR: 0.54; p=0.005). In pemetrexed pre-treated patients, re-treatment with a pemetrexed/platinum combination significantly reduced the risk-of-death than pemetrexed alone (HR: 0.11; p<0.001). In conclusion, SL-chemotherapy seems to be active in MPM-patients, particularly in younger patients with ECOG-PS0 and prolonged TTP after FL-pemetrexed-based chemotherapy. In selected patients, re-challenge with pemetrexed-based regimens, preferentially associated with platinum-compound, appears to be an option for SL-setting. Considering the important limitations of this study, due to retrospective nature and the possible selection bias, prospective clinical trials are warranted to clarify these issues.

Advances in the biology of malignant pleural mesothelioma.

Malignant pleural mesothelioma is a highly aggressive cancer with a very poor prognosis. Although the mechanism of carcinogenesis is not fully understood, approximately 80% of malignant pleural mesothelioma can be attributed to asbestos fiber exposure. This disease is largely unresponsive to conventional chemotherapy or radiotherapy, and most patients die within 10-17 months of their first symptoms. Currently, malignant pleural mesothelioma therapy is guided by clinical stage and patient characteristics rather than by the histological or molecular features of the tumor. Several molecular pathways involved in malignant pleural mesothelioma have been identified; these include cell cycle regulation, apoptosis, growth factor pathways, and angiogenesis. Unfortunately, several agents targeting these processes, including erlotinib, gefitinib, and imatinib, have proven ineffective in clinical trials. A greater understanding of the molecular pathways involved in malignant pleural mesothelioma is needed to develop better diagnostics, therapeutics, and preventative measures. Moreover, understanding the biological basis of mesothelioma progression may facilitate personalized treatment approaches, and early identification of poor prognostic indicators may help reduce the heterogeneity of the clinical response. This paper reviews advances in the molecular biology of malignant pleural mesothelioma in terms of pathogenesis, the major molecular pathways and the associated therapeutic strategies, and the roles of biomarkers.