Novel and Future Treatment Options in Mesothelioma: A Systematic Review

Telomere length and TERT polymorphisms as biomarkers in asbestos-related diseases

BACKGROUND

Asbestos exposure has been proposed as a risk factor for shorter telomere length. The aim of our study was to investigate whether telomere length in leukocytes and hTERT genetic polymorphisms may serve as potential biomarkers for the risk of developing asbestos-related diseases and as biomarkers of progression and chemotherapy response rate in malignant mesothelioma (MM).

SUBJECTS AND METHODS

We conducted two retrospective studies. In the first study, a case-control study, telomere length and hTERT polymorphisms were determined in patients with MM, subjects with pleural plaques and controls without the asbestos related disease, who were occupationally exposed to asbestos. In the second study, a longitudinal observational study, telomere length was also determined in samples from MM patients before and after chemotherapy. Telomere length was determined by monochromatic multiplex quantitative polymerase chain reaction (PCR), while competitive allele-specific PCR was used to genotype hTERT rs10069690, rs2736100 and rs2736098. Logistic regression and survival analysis were used in statistical analysis.

RESULTS

Patients with MM had shorter telomere length than subjects with pleural plaques (p < 0.001). After adjustment for age, rs2736098 CT, and rs10069690 TT and CT+TT genotypes were significantly associated with a higher risk of MM (padj = 0.023; padj = 0.026 and padj = 0.017), while rs2736100 AA and CA+AA genotypes conferred to a lower risk for MM compared to all other subjects (padj = 0.017, and padj = 0.026). Telomere length was not associated with a response to chemotherapy (p > 0.05) or time to disease progression (p > 0.05). Carriers of one or two polymorphic rs10069690 T alleles had a good response to chemotherapy (p = 0.039, and p = 0.048), these associations remained statistically significant after adjustment for age (padj = 0.019; padj = 0.017). Carriers of two polymorphic rs2736100 A alleles had a longer time to disease progression (p = 0.038).

CONCLUSIONS

Shorter telomere length and hTERT polymorphisms may serve as a biomarker for the risk of developing MM. Additionally, rs10069690 and rs2736100 polymorphisms, but not telomere length, were associated with a chemotherapy response or MM progression.

The Impact of 3D Nichoids and Matrix Stiffness on Primary Malignant Mesothelioma Cells

Malignant mesothelioma is a type of cancer that affects the mesothelium. It is an aggressive and deadly form of cancer that is often caused by exposure to asbestos. At the molecular level, it is characterized by a low number of genetic mutations and high heterogeneity among patients. In this work, we analyzed the plasticity of gene expression of primary mesothelial cancer cells by comparing their properties on 2D versus 3D surfaces. First, we derived from primary human samples four independent primary cancer cells. Then, we used Nichoids, which are micro-engineered 3D substrates, as three-dimensional structures. Nichoids limit the dimension of adhering cells during expansion by counteracting cell migration between adjacent units of a substrate with their microarchitecture. Tumor cells grow effectively on Nichoids, where they show enhanced proliferation. We performed RNAseq analyses on all the samples and compared the gene expression pattern of Nichoid-grown tumor cells to that of cells grown in a 2D culture. The PCA analysis showed that 3D samples were more transcriptionally similar compared to the 2D ones. The 3D Nichoids induced a transcriptional remodeling that affected mainly genes involved in extracellular matrix assembly. Among these genes responsible for collagen formation, COL1A1 and COL5A1 exhibited elevated expression, suggesting changes in matrix stiffness. Overall, our data show that primary mesothelioma cells can be effectively expanded in Nichoids and that 3D growth affects the cells' tensegrity or the mechanical stability of their structure.

Serum Calretinin and Genetic Variability as a Prognostic and Predictive Factor in Malignant Mesothelioma

Calretinin is a promising diagnostic biomarker for malignant mesothelioma (MM), but less is known about its prognostic role. Our aim was to evaluate the association between serum calretinin concentration or genetic factors and the survival or outcome of cisplatin-based chemotherapy in MM. Our study included 265 MM patients. Serum calretinin concentration was determined using ELISA. Patients were genotyped for seven polymorphisms in CALB2, E2F2, MIR335, NRF1, and SEPTIN7 using competitive allele-specific PCR. Nonparametric tests, logistic regression, and survival analysis were used for statistical analysis. Higher serum calretinin concentration was associated with shorter progression-free (PFS) (HR = 1.18 (1.02-1.37), p = 0.023) and overall survival (OS) (HR = 1.20 (1.03-1.41), p = 0.023), but the association was not significant after adjusting for clinical factors (HR = 1.05 (0.85-1.31), p = 0.653 and HR = 1.06 (0.84-1.34), p = 0.613, respectively). SEPTIN7 rs3801339 and MIR335 rs3807348 were associated with survival even after adjustment (HR = 1.76 (1.17-2.64), p = 0.007 and HR = 0.65 (0.45-0.95), p = 0.028, respectively). Calretinin concentration was higher in patients who progressed after treatment with cisplatin-based chemotherapy (1.68 vs. 0.45 ng/mL, p = 0.001). Calretinin concentration above 0.89 ng/mL was associated with shorter PFS and OS from the start of chemotherapy (HR = 1.88 (1.28-2.77), p = 0.001 and HR = 1.91 (1.22-2.97), p = 0.004, respectively), even after adjusting for clinical factors (p < 0.05). MIR335 rs3807348 was associated with a better response to chemotherapy (OR = 2.69 (1.17-6.18), p = 0.020). We showed that serum calretinin is associated with survival and chemotherapy treatment outcomes in MM and could serve as a predictive biomarker.

Effects of SETD2 on telomere length and malignant transformation property of Met-5A after one-month crocidolite exposure

Crocidolite is a carcinogen contributing to the pathogenesis of malignant mesothelioma. This study aimed to characterize the possible telomere-related events mediating the malignant transformation of mesothelial cells with and without SETD2 under crocidolite exposure. The crocidolite concentration resulting in 90% viable SETD2 knockout Met-5A (Met-5ASETD2-KO) and Met-5A were estimated to be 0.71 μg/cm2 and 1.8 μg/cm2, respectively, during 72 h of exposure, which was further employed in chronical crocidolite exposure during a 72 h exposure interval per time up to 1 month. Chronical crocidolite-exposed Met-5ASETD2-KO (chronical Cro-Met-5ASETD2-KO) had higher colony formation and increased telomerase reverse transcriptase (TERT) protein levels than chronical crocidolite-exposed Met-5A (chronical Cro-Met-5A) and Met-5ASETD2-KO. Chronical Cro-Met-5ASETD2-KO had longer telomere length (TL) than chronical Cro-Met-5A, although there were no changes in TL for either chronical Cro-Met-5A or chronical Cro-Met-5ASETD2-KO compared with their corresponding cells without crocidolite exposure. BIBR 1532, an inhibitor targeting TERT, partially reduced colony formation and TL for chronical Cro-Met-5ASETD2-KO, while BIBR 1532 reduced TL but had no effect on colony formation for chronical Cro-Met-5A. Therefore, SETD2 deficient mesothelial cells are susceptible to malignant transformation during chronical crocidolite exposure, and TERT-dependent TL modification likely partially drives SETD2 loss-mediated early onset of mesothelial malignant transformation.

Global, Regional, and National Burden of Mesothelioma 1990-2019: A Systematic Analysis of the Global Burden of Disease Study 2019

Rationale: Mesothelioma has become a major health burden since World War II because of the use of asbestos. Although many countries have imposed bans on asbestos, there remain significant mortality and morbidity from mesothelioma because of its long latent period and aggressiveness. Also, the use of asbestos is increasing in low-income countries, potentiating risk of mesothelioma in the coming decades. Assessment of the global burden of mesothelioma is required to take proper measures against the disease. Objectives: To assess the burden of mesothelioma from 1990 to 2019 at the global, regional, and national levels and to investigate patterns according to sex, age, sociodemographic index, and risk factors. Methods: The numbers, rates, and age-standardized rates of incidence, death, and disability-adjusted life years (DALYs) of mesothelioma in 204 countries and territories from 1990 to 2019 were estimated using vital registration and cancer registry data. The relationship between sociodemographic index and age-standardized DALY rate was determined, and DALYs attributable to occupational exposure to asbestos were calculated. Results: In 2019, there were 34,511 (95% uncertainty interval [UI], 31,199 to 37,771) incident cases of mesothelioma globally, with an age-standardized rate of 0.43 per 100,000 persons (95% UI, 0.38 to 0.47), which decreased between 1990 and 2019 by -12.6% (95% UI, -21.8% to -2.3%). Mesothelioma was responsible for 29,251 (95% UI, 26,668 to 31,006) deaths in 2019, with an age-standardized rate of 0.36 deaths per 100,000 persons (95% UI, 0.33 to 0.39), which decreased between 1990 and 2019 by -9.6% (95% UI, -17.8% to -1.1%). The age-standardized incidence rate increased in central Europe between 1990 and 2019 by 46.1% (95% UI, 16.6% to 72.4%). The Netherlands, Australia, and the United Kingdom had the highest age-standardized incidence rates. Incidence rates were higher in men than in women ages 45-49 to 90-94 years, peaking at 85-89 years. Occupational exposure to asbestos contributed to 85.2% (95% UI, 82.1% to 88.1%) of DALYs. Conclusions: The global burden of mesothelioma is decreasing in terms of age-standardized incidence and mortality rates. Mesothelioma remains a substantial public health challenge in many parts of the world.

Medical application of the monoclonal antibody SKM9-2 against sialylated HEG1, a new precision marker for malignant mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor of the pleural cavity. Pathologically distinguishing MPM from other pleural lesions is often difficult. We searched for marker antigens to facilitate the pathological diagnosis of MPM and found useful markers for the pathological detection of malignant mesothelioma. Among them, the anti-mesothelioma monoclonal antibody SKM9-2, which was isolated as a clone binding to specimens of MPM (but not to specimens of lung adenocarcinoma) by immunohistochemical screening, showed higher specificity and sensitivity than traditional mesothelioma markers. SKM9-2 recognizes both sialylated O-glycans and peptide sequences in HEG1, and its glycan modifications are specific to mesothelioma. New effective treatments for MPM are needed because the prognosis of patients with MPM is usually poor. SKM9-2 can be used as a seed for next-generation antibody drugs with strong cytotoxic activities. In this review, we have summarized our research on antibody development for MPM diagnosis and treatment.

Comparison of Survival by Multimodal Treatment Regimen Among Malignant Pleural Mesothelioma Patients in an Integrated Health System

BACKGROUND

Optimal therapy for malignant pleural mesothelioma (MPM) remains unclear. We compared overall survival in patients with MPM after various multimodal treatment regimens including combinations of immunotherapy, chemotherapy, and surgery.

PATIENTS AND METHODS

We examined MPM patients treated within our integrated health system from January 1, 2009 to December 31, 2020. Patients were grouped based on treatment regimen: chemotherapy alone (CT), immunotherapy with or without chemotherapy (iCT), surgery with chemotherapy (sCT), and surgery with immunotherapy and chemotherapy (siCT). We analyzed baseline characteristics and overall patient survival among these groups and several subgroups.

RESULTS

One hundred seventy-nine patients were included. Among the study groups, there was no difference in age, sex, race/ethnicity, Charlson Comorbidity Index, or Eastern Cooperative Oncology Group performance status. Patients treated with CT (N = 109), iCT (N = 35), sCT (N = 26), and siCT (N = 9) had median (95% confidence interval) survivals of 11.7 (9.9-16.3), 18.2 (14.5-29.8), 20.7 (11.6-37.2), and 22.6 (19.7-37.8) months, respectively (P < .001). Median survival among patients with and without immunotherapy was 19.7 (17.4-29.8) and 12.3 (10.6-17.3) months, respectively (P = .023). Median survival among patients with and without surgery was 21.7 (17.6-34.8) and 13.6 (11.5-17.3) months, respectively (P = .007). Patients with biphasic/sarcomatoid subtypes who received immunotherapy experienced 76.2% (55.8%-100.0%) 12 month survival vs. 13.6% (4.8%-39.0%) among those who did not (P < .001).

CONCLUSION

MPM patients receiving surgery and immunotherapy as part of multimodal treatment regimens experienced the longest survival. Surgery and immunotherapy are each associated with survival. Further investigations are warranted to assess the benefit of immunotherapy within multimodal treatment regimens for MPM.

Near Missed Case of Occupational Pleural Malignant Mesothelioma, a Case Report and Latest Therapeutic Options

Asbestos use started to be gradually banned in Europe from 1991 onwards, and there are currently strict occupational exposure limits for asbestos. However, malignant mesothelioma has a long latency time (in some cases up to 50-60 years), so the risks related to asbestos exposure should not be forgotten. Considering the increased risk of lung cancer following the inhalation of asbestos fibers, lifetime health monitoring should be considered in people occupationally exposed to asbestos, with an emphasis on the respiratory system. An assessment of their occupational history should be performed rigorously, especially in the areas with a history of asbestos production/use, as this is a key element for an early diagnosis and appropriate treatment. This case report presents a near-missed case of occupational pleural malignant mesothelioma. The latency time between the first asbestos exposure and the diagnosis of occupational pleural malignant mesothelioma was 49 years. The accurate diagnosis was made two years after the first symptoms appeared.