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Evaluating Genetic Markers
December  2018

‚ÄčAll of medicine is evolving rapidly. But one of the fastest changing areas is oncology. Traditionally cancers were evaluated and treated based on the extent (size and dispersion) of the cancer when it was discovered and/or treated. This is captured in the TNM (Tumor, Node, Metastases) classification system.

Tumors are also graded based on the histology (appearance of the cells under the microscope). The tumor cells may range from well-differentiated to anaplastic. An example of this is the Gleason grading system used in prostate cancer.

But more recently, the biggest change has occurred in the evaluation of genetic molecular markers or their cellular products. Tumor markers such as prostate specific antigen (PSA) or carcinoembryonic antigen (CEA) have been recognized for years as proteins produced in excess by some prostate or colon cancers.

Some molecular markers are found in cancers arising from differing organs. One example would be Microsatellite instability (MSI) by genetic sequencing which is associated with mismatch repair deficiency (MMR-D) by immunohistochemistry of the tumor. As these markers are studied and validated as contributing to treatment and outcomes, they are
being added to the diagnostic evaluation of the tumor.

On a macro level prognosis is determined by the extent of the tumor (size and spread), the aggressiveness of the tumor cells and markers that may indicate a more treatable versus less treatable tumor. The addition of molecular markers introduces a challenge in crafting tumor guidelines since each of these factors must be considered in the proper proportion based on the contribution to prognosis. In addition guidance still must be available in cases where the tumor occurred prior to the addition of newer molecular markers.

SCOR Global Life in the Americas is in the process of updating the tumor guidelines in the SCOR Online Electronic Manual (SOLEM) to include recognized molecular markers. We expect this process to be ongoing as oncology continues to evolve.