Biomarker Detects Spread of Brain Tumors

A novel biomarker for malignant astrocytomas, the most common form of intracranial brain tumor, provides physicians with a new noninvasive test to track the success of treatments.

The biomarker, a protein known as "soluble attractin,” is normally absent in the central nervous system (CNS) and is undetectable in cerebral spinal fluid (CSF) unless malignant astrocytomas are present in the CNS. CSF is a liquid that bathes the brain and acts as a reservoir, which can be sampled for analysis of proteins secreted by CNS tumors.

Scientists at Emory University's Winship Cancer Institute (Atlanta, GA, USA) identified the novel biomarker and uncovered a potential role the marker may play when a tumor spreads or comes back after treatment. The study was published in the November 2006 issue of the journal Clinical Cancer Research.

"Using proteomic analyses of the CSF of patients with brain tumors, we have identified for the first time that attractin levels are elevated in patients with high-grade astrocytoma,” said Erwin Van Meir, Ph.D., professor of neurosurgery and hematology/oncology and lead author of the study. "Because few noninvasive methods are available for monitoring CNS malignancies, there is an urgent need to find reliable indicators.”

Prof. Van Meir and colleagues found that there were elevated attractin levels in 97 % of malignant astrocytomas, with the highest levels in grade IV tumors. The grade of a tumor reflects the level of abnormality its cells exhibit and how quickly the tumor is likely to grow and spread, and is a predictor of patient outcome.

The team also found that attractin plays a key role in the motility of the cancer cells, which influences their ability to spread in the brain, a major cause of recurrence of malignant astrocytoma. Secreted by the tumors, attractin induces cancer cells to migrate, although the mechanism by which it does this is not known. Knowing that attractin modulates the migration and possibly the recurrence of these tumors makes it a promising target for future therapeutic intervention, said Prof. Van Meir. "Our studies suggest that measuring attractin levels in patients with grades II-IV astrocytoma should be explored further as a potential biomarker for monitoring the growth of these tumors or as a potential new target for therapy.”