Soluble mesothelin-related peptides (SMRP) is a protein that has been identified as a potential tumor marker for malignant mesothelioma. A tumor marker is a substance produced by cancerous tissues that can be used to diagnose the existence of a malignant event, as well as to indicate the current state of the cancer. The ideal tumor marker will have at least two very important features:

1. It will only be produced by a single type of tumor, which will allow the diagnosis of particular cancers with perfect accuracy; and
2. It will be expressed from the beginning of the tumor’s life, which will make false negatives virtually impossible.

Few, if any, presently identified markers meet both of these requirements, but this research is ongoing and tumor markers represent some of the most exciting and promising work in cancer studies.

A number of previous studies have shown SMRP to have excellent potential as a marker for mesothelioma. Researches from Germany have recently released results of a study regarding the stability of SMRP under different lab conditions. Their goal was to understand the conditions under which SMRP would still be effective as a marker and under what conditions its efficacy would be compromised.

Introduction to the Study

To study the stability of SMRP and understand the parameters of its efficacy, the authors identified three variations that would impact a marker’s diagnostic value:

1. Biological factors, such as inherent intra- and inter-individual fluctuations.
2. Pre-analytical factors, such as handling and/or conditions of storage.
3. Analytical factors, such as assay imprecision.

To see how these factors would impact SMRP, they collected serum from 98 people, all of whom were considered healthy and none of whom had any known asbestos exposure. There were 47 men and 51 women. The serum was then stored under different conditions: 5 days at -80 degrees centigrade; 5 days at room temperature and then a number of thaw/freeze cycles over another 5 days. SMRP concentrations were determined using the MESOMARK ELISA kit. They used a number of statistical techniques to establish a baseline SMRP concentration in healthy people, which has been missing from previous SMRP research.

Results and Conclusions

The authors determined a baseline SMRP concentration between 1.5 and 1.6 nmol/L in the 95th percentile of the population. They noted that SMRP showed little variation to age-based biological variation, as overall concentration was statistically similar between those under 60 and those over 60. As regards structural stability due to storage conditions, the only significant differences involved those samples that experienced a high number (10+) of freeze and thaw cycles. They did not describe statistically significant findings when comparing serum stored at room temperature to serum stored at -80 degrees centigrade.

The authors confirm SMRP’s excellent potential as a tumor marker for malignant mesothelioma. They state that more work needs to be done, but that their results, combined with those of previous studies, show its potential to materially improve medicine’s ability to diagnose, and therefore treat, malignant mesothelioma.

Labels: mesothelioma