Is soluble mesothelin-related protein an upfront predictive marker of pleural mesothelioma? A prospective study on Italian workers exposed to asbestos.

OBJECTIVE: Soluble mesothelin-related peptide (SMRP) may be useful in the diagnosis and detection of early stage mesothelioma. We investigated the SMRP upfront predictive role for mesothelioma in asbestos-exposed workers. METHODS: A total of 1,715 subjects underwent a first visit and were invited for a follow-up after 1 and 2 years, with a clinical examination and blood sampling. SMRP was measured by an ELISA assay. RESULTS: Median SMRP at the first visit was 0.45 [interquartile range (IQR) i.e. 25th-75th percentile: 0.30-0.67 nmol/l]. In all, 1,676 subjects (97.8%) were followed up for a median period of 47.1 months. SMRP was measured at the first visit and at both follow-up visits in 1,536 subjects. At follow-up, 3 subjects were diagnosed with an epithelioid mesothelioma. In these cases, SMRP at the first visit ranged from 0.17 to 0.52 nmol/l. Malignant pleural mesothelioma was diagnosed 9-17 months after the last SMRP evaluation. No SMRP variation was observed during the follow-up. Other 61 miscellaneous cancers were diagnosed (median SMRP at first visit: 0.50 nmol/l, IQR: 0.34-0.71 nmol/l). CONCLUSIONS: Our results did not support the usefulness of SMRP as an early marker for the detection of the disease for a time interval of 1 year.

Diagnostic value of mesothelin in pleural fluids: comparison with CYFRA 21-1 and CEA.

CYFRA 21-1 and CEA have been applied for the differential diagnosis of malignant pleural mesothelioma (MPM). The soluble mesothelin-related peptide (SMRP) has been proposed as a specific marker for distinguishing MPM from benign diseases and other malignancies in pleural effusions (PEs). In this study, we evaluated the usefulness of SMRP in PEs in the detection of mesotheliomas by comparing it with that of CYFRA 21-1, CEA, and with cytological examination. One hundred and seventy-seven consecutive patients (57 MPM, 64 metastatic tumors, and 56 benign diseases) were evaluated using commercial tests. The performance of the markers was analyzed by standard ROC analysis methods, using the area under a ROC curve (AUC) as a measure of accuracy. CYFRA 21-1 better differentiated malignant from benign effusions. The corresponding area under the receiver operating characteristic curve was 0.87, while it was 0.74 for SMRP and 0.64 for CEA (p < 0.001). Conversely, SMRP differentiated MPM from all other PEs better than both CYFRA 21-1 and CEA (AUC = 0.84, 0.76, and 0.32, respectively, p = 0.003). Low levels of CEA were associated with a MPM diagnosis. The AUC for differentiating MPM from metastases was 0.81 for SMRP, 0.61 for CYFRA 21-1, and 0.20 for CEA (p < 0.001). In cases with negative or suspicious cytology, SMRP and CYFRA 21-1 identified 36/71 and 46/66 malignant PEs (29 and 31 MPM, respectively). Only 1 MPM showed a high CEA concentration. No single marker showed the best performance in any comparison. Results suggest that SMRP could improve CYFRA 21-1 and CEA accuracy in the differential diagnosis of MPM.

Individual predictors of increased serum mesothelin in asbestos-exposed workers.

The soluble mesothelin-related peptide (SMRP), a candidate marker for screening of subjects with asbestos exposure, is influenced by some individual and clinical factors. The aim of this study was to quantify the role of age, smoking, weight, presence of diseases and exposure to asbestos on serum SMRP levels in a large series of subjects exposed to asbestos, possible candidates for mesothelioma screening. One thousand seven hundred and four participants underwent clinical examination and were interviewed on medical anamnesis, occupation, smoking and weight. SMRP was measured by an ELISA assay. Overall, median SMRP was 0.4 (IQR 25-75: 0.3-0.7) nmol/l. It was higher in current smokers and in subjects with a cumulative asbestos exposure >50 ff/cc/years than in all the other subjects (p < 0.001 and p = 0.002, respectively). SMRP was positively correlated with age (ρ = 0.11, p < 0.001) and, inversely, with BMI (ρ = -0.15, p < 0.001). SMRP was lower in healthy subjects (n = 1,217: median 0.4 nmol/l) than in subjects with malignant tumors (n = 118: 0.5 nmol/l; p = 0.01), asbestos-related pleural lesions (plaques or thickenings, n = 152: 0.6 nmol/l; p < 0.001) and other benign diseases (n = 182: 0.5 nmol/l; p = 0.04). Multivariate analysis revealed significant predictors of increased SMRP: age >57 years, current smoking, a positive anamnesis for cancer and for asbestos-related pleural lesions, and BMI < 25. Some clinical and demographic variables are associated with serum SMRP levels. The degree of these associations is low, nevertheless they should be accounted for in the interpretation of SMPR as a candidate marker predictive of mesothelioma. The potential predictive value of serum SMRP in screening/surveillance programs must be validated in prospective studies.

Osteopontin plasma level does not detect prostate cancer in patients referred for diagnostic prostate biopsy.

BACKGROUND: Prostate cancer is the second most frequent cause of tumor-related deaths in men in Western countries. The selection and evaluation of new markers might help to overcome the limits of the most widely used diagnostic tool, the prostate-specific antigen (PSA) test, often combined with digital rectal examination (DRE). Osteopontin (OPN) is an integrin-binding glycoprotein that has recently been shown to be related to tumor development, progression and metastasis in both experimental and clinical studies. The present study compares plasma OPN levels and tumor presence and grade in a group of PSA/DRE-positive patients referred for diagnostic prostate biopsy. METHODS: Plasma OPN levels were measured by enzyme-linked immunosorbent assay in blood samples of 194 PSA/DRE-positive patients referred for diagnostic prostate biopsy. OPN measurements were compared with PSA levels and tumor presence and grade as established by needle biopsy. RESULTS: Plasma OPN levels were not increased in patients with prostate cancer, and in patients with high-grade prostate cancer the plasma OPN levels were not different from those in patients with low-grade or no prostate cancer. CONCLUSIONS: In PSA/DRE-positive patients referred for diagnostic prostate biopsy, OPN does not appear to be a plasma marker able to detect prostate cancer or high-grade prostate cancer.

Prognostic role of serum sialyl Lewisx (CD15s) in colorectal cancer.

OBJECTIVE: Sialyl Lewis(x) (sLe(x)) is one ligand for E selectin (CD62E), a glycoprotein that is expressed on activated endothelial cells. Adhesion mediated by endothelial E selectin and sLe(x) expressed on human tumor cells could be relevant for the development of metastases. The aim of this study was to investigate whether or not a correlation exists between pre-operative levels of ganglioside serum sLe(x) and disease-free interval and survival in colorectal cancer patients. PATIENTS AND METHODS: Thirty Duke's B and 52 Duke's C patients undergoing resection for colorectal cancer were studied. The median follow-up time was 34.8 months. A pool of 57 sera from normal subjects was used as an Internal Normal Standard (INS). sLe(x) analyses were performed by a thin layer chromatography (TLC) immunostaining technique. Results were expressed as the ratio (R) between bands of INS and bands from each neoplastic serum. RESULTS: The median R value was 0.80 in normal subjects, 0.70 in Duke's B patients and 1.0 in Duke's C patients. No significant differences were detected between sLe(x) concentrations in sera from normal and neoplastic subjects (p = 0.1). Using an arbitrary cutoff of R = 0.9, the mean disease-free interval in the whole series was 47.4 months for R <0.9 and 126.0 months for R > or = 0.9 (p = 0.04). The survival time was 76.8 months for patients with R values <0.9 and 156.3 months for patients with R values > or =0.9 (p = 0.1). CONCLUSIONS: High serum levels of ganglioside sLe(x) significantly correlate with a favorable prognosis and with a lower occurrence of metastases. It is conceivable that soluble sLe(x) may compete with membrane-bound sLe(x) in the course of interactions between activated endothelium and tumor cells that have reached the circulation.