Introduction: Malignant pleural mesothelioma (MPM) is a relatively rare tumor, with the epithelioid type occurring more frequently. Several biomarkers have been suggested for screening and early diagnosis of MPM. Currently, high levels of soluble mesothelin-related peptides (SMRP), plasma osteopontin (pOPN) and vimentin have been reported in patients with MPM as promising markers for diagnosis, but their clinical use in monitoring is still discussed. The aim of our study was to evaluate the usefulness of these substances as markers of the clinical response to treatment in patients suffering from epithelioid mesothelioma. Methods: 219 serum samples from 56 patients were collected during follow-up and the clinical response to therapy was recorded. Percentage differences between 2 consecutive measurements of SMRP, osteopontin and vimentin (Δ markers) by means of commercially available kits were correlated with changes in the clinical course. Results: Δ SMRP, Δ pOPN and Δ vimentin showed statistically significant differences between the disease categories stable disease, partial response and disease progression (p = 0.0001, p = 0.035 and p = 0.0025 for SMRP, pOPN and vimentin, respectively). Moreover, contingency table analysis showed statistically significant differences between clinical response and Δ of each marker clustered into 3 groups (<-20%, between -20% and +20%, >+20%). Conclusions: The time course of Δ SMRP and Δ vimentin was strongly associated with disease status, and so was the time course of pOPN, albeit to a lesser extent. These markers appear to be particularly effective in cases of partial response and disease progression, while their possible use in stable disease should be better investigated.

Exposure to asbestos is the main cause of malignant pleural mesothelioma (MPM), a highly aggressive cancer of the pleura. Since the only tools for early detection are based on radiological tests, some authors focused on serum markers (i.e., mesothelin). The aim of this study was the evaluation of new serum biomarkers to be used individually or in combination, in order to improve the outcome of patients whose disease would be diagnosed at an earlier stage. Serum and plasma were available from 43 subjects previously exposed to asbestos and 27 MPM patients, all being epithelioid type. All the new markers found differentially expressed in MPM and healthy subjects, by proteomic and genomic approaches, have been validated in the serum by the use of specific ELISA. The combined approach, using tools of genomics and proteomics, is found to be highly innovative for this type of disease and led to the identification of new serum markers in the diagnosis of MPM. These results, if confirmed in a larger series, may have a strong impact in this area, because early detection of this cancer in people at high risk could significantly improve the course of the disease and the clinical approach to an individualized therapy.

Background and aims: Increased concentrations of soluble mesothelin-related peptides (SMRP) have been found in sera of patients with malignant pleural mesothelioma (MPM) even if a relatively high rate of false positives has hampered their clinical use as a tumor marker. Individual SMRP levels could be affected by polymorphic elements. The aim of this study was to investigate the association between single nucleotide polymorphisms within the promoter-5'UTR regions and SMRP levels in healthy asbestos-exposed individuals and patients suffering from MPM. Methods: The promoter-5'UTR regions of the mesothelin gene were genotyped in 59 healthy asbestos-exposed subjects and 27 MPM patients. SMRP levels were measured using a commercially available ELISA kit. Results: Two novel polymorphisms, an A>C variant (called New1) and a C>T variant (called New2), were identified. In healthy subjects, high SMRP levels were associated with the C-variant of New1, with an average 1.62-fold increase compared with AA homozygotes (p<0.0001). Most of the C-allele carriers had SMRP levels above the threshold of 1.00 nM. We set two different SMRP cutoffs on the basis of the combined New1+New2 genotypes. Conclusions: New1-New2 genotypes could be employed as markers for setting individualized and appropriate thresholds of “normality” when SMRP is used in surveillance programs of asbestos-exposed people.

Although in most developed countries the use of asbestos is banned, there is still a consistent portion of the world where asbestos extraction, trading and manufacturing of asbestos-made products is largely diffuse. Worldwide, hundreds of millions of people are at risk of developing an asbestos caused disease because of occupational, environmental or domestic exposure. The WHO estimates that asbestos is responsible for more than 100,000 deaths yearly. This scenario has prompted the research on biomarkers potentially useful for early diagnosis, prognosis and preventive programs on exposed population as well. Here we reviewed the up-to-date literature on this field of research highlighting that along with mesothelin and osteopontin (OPN), some more recently investigated molecules, such as high mobility group box 1 (HMGB1) protein, fibulin-3 and some miRNAs showed very promising. Most of the carried-out studies showed an interesting diagnostic and prognostic performance of some biomarkers, but since they usually lack adequate either specificity or sensitivity, their use in screening or in preventive programs is still not recommended on a routine basis. However, this review suggests the need for more reliable experimental design involving larger population and preferring longitudinal screening of asbestos exposed individuals rather than a single baseline assessment investigation. In addition, given their better diagnostic accuracy, the use of panels including several biomarkers is highly recommended.

Background: Malignant pleural mesothelioma (MPM) is a fatal tumor with a poor prognosis. The recent developments of liquid biopsies could provide novel diagnostic and prognostic tools in oncology. However, there is limited information about the feasibility of this technique for MPMs. Here, we investigate whether cancer-specific DNA sequences can be detected in pleural fluids and plasma of MPM patients as free circulating tumor DNA (ctDNA). Methods: We performed whole-exome sequencing on 14 tumor biopsies from 14 patients, and we analyzed 20 patient-specific somatic mutations with digital droplet PCR (ddPCR) in pleural fluids and plasma, using them as cancer-specific tumor biomarkers. Results: Most of the selected mutations could be detected in pleural fluids (94%) and, noteworthy, in plasma (83%) with the use of ddPCR. Pleural fluids showed similar levels of somatically mutated ctDNA (median = 12.75%, average = 16.3%, standard deviation = 12.3) as those detected in solid biopsies (median = 21.95%; average = 22.21%; standard deviation = 9.57), and their paired difference was weakly statistically significant (p = 0.048). On the other hand, the paired difference between solid biopsies and ctDNA from plasma (median = 0.29%, average = 0.89%, standard deviation = 1.40) was highly statistically significant (p = 2.5 × 10⁻⁷), corresponding to the important drop of circulating somatically mutated DNA in the bloodstream. However, despite the tiny amount of ctDNA in plasma, varying from 5.57% down to 0.14%, the mutations were detectable at rates similar to those possible for other tumors. Conclusions: We found robust evidence that mutated DNA is spilled from MPMs, mostly into pleural fluids, proving the concept that liquid biopsies are feasible for MPM patients.

Background: Sporadic medullary thyroid carcinoma (sMTC) is an uncommon neoplasia arising from the calcitonin-producing parafollicular cells of the thyroid. Previous studies evaluated whether single nucleotide polymorphisms (SNPs) within RET (a pivotal proto-oncogene for this disease) are associated with the risk for developing sMTC, but the results are inconclusive. Methods: In this work, we evaluated the association of RET -SNPs c.74-126G>T (rs2565206), p.Gly691Ser (rs1799939, G>A), p.Leu769 = (rs1800861, G>T), p.Ser836 = (rs1800862, C>T), and p.Ser904 = (rs1800863, C>G) (listed in the order of their chromosomal location) with sMTC. This is one of the largest case – control association studies carried out on sMTC, including 585 sMTC cases (negative for germline mutations within RET ), 1529 patients affected by sporadic nonmedullary thyroid carcinoma (sNMTC), and 989 healthy controls, from central and southern Italy and collected in the period 2000–2017. Results: sNMTC patients showed similar genotype and allele frequencies compared with healthy controls. On the other hand, among sMTC patients, the T-allele of p.Leu769 = was less frequent (OR = 0.70 [CI 0.58–0.84], p = 1.9 × 10 ⁻⁴ ) and rare homozygotes TT showed an OR = 0.32 ([CI 0.17–0.60], p = 2.3 × 10 ⁻⁴ ). Moreover, a statistically significant excess of the haplotype 2 (characterized by the alleles T-G-G-C-C of the listed SNPs) was observed ( p = 3.9 × 10 ⁻³ ). The SNPs were not associated with the expression of RET mRNA, that is, they did not exert an effect in cis as quantitative trait locus (cis-eQTL). However, a strong eQTL association was found for p.Leu769 = and the neighboring gene CSGALNACT2 ( p = 9.3 × 10 ⁻⁵⁰ ; effect-size = −0.65), whose function in cancer is unknown. Conclusions: This study shows that specific RET haplotypes, in particular haplotype 2 and the T-allele of p.Leu769 = , are associated with a reduced risk of sMTC in Italians.