Background and purpose: Building-up evidence suggests that soluble mesothelinrelated protein (SMRP) carries a diagnostic and a prognostic value in malignant pleural mesothelioma (MPM). Egypt suffers endemic asbestosis and thus this study was conducted to evaluate the sensitivity and specificity of SMRP in patients with MPM and to correlate this marker with known clinicopathological prognostic factors.
Material and methods: During the period from January 2006 till March 2008, Serum samples were obtained from MPM patients presenting to the Egyptian National Cancer Institute, Cairo University. Serum samples were provided from patients with breast cancer and from healthy individuals to function as controls. The SMRP was assayed using the ELISA technique and correlations were made with different clinico-pathological prognostic parameters.
Results: 83 patients (50 MPM and 33 breast cancer) as well as 22 healthy individuals were enrolled in this study. Serum SMRP levels were not different between patients with breast cancer and healthy controls (p > 0.05). However, there was a significant difference between MPM patients and the other two groups (p < 0.0001). ROC analysis showed an AUC = 0.765 for differentiating between the controls and MPM with a best statistical cut-off of 7.22nM/L (sensitivity = 66 % , specificity = 70.9 % ). The mean SMRP concentrations were significantly higher in patients with advanced disease (p = 0.038), poor performance status (p = 0.017) and high alkaline phosphatase (p = 0.015). The mean SMRP concentrations were also higher in males, elderly patients, asbestos-exposed patients, epithelioid subtypes and patients with high platelet and leucocytic counts. However, these differences did not reach statistical significance
Conclusions: This study confirms that SMRP is of considerable sensitivity and specificity in Egyptian patients with MPM. Higher levels are frequently seen in patients with high tumor burden, which could be helpful in monitoring response to therapy.
Key words: Malignant pleural mesothelioma (MPM) - Soluble mesothelin related protein (SMRP)- Sensitivity - Specificity - Asbestos.