Deadly Brain Cancer Genes Identified

Gliomas are a type of tumor that starts in the glial cells of the central nervous system, the brain and spinal cord, and glia are the support cells of the nervous system, providing physical support and insulation to neurons.

Glioblastoma multiforme, also known as grade 4 astrocytoma, is the most common and aggressive form of glioma and for this subtype of cancer, patients rarely survive much longer than a year from diagnosis, even when surgery, radiation, and chemotherapy are used, prognosis is poor.

Scientists at the First Hospital of China Medical University (Shenyang, People's Republic of China) examined tissue samples from 297 people with brain tumors and of these, 127 people had glioblastoma and the others had less aggressive forms of glioma. All tissue samples were immediately snap-frozen in liquid nitrogen after surgery.

A hematoxylin and eosin–stained frozen section was prepared from each sample to assess the percentage of tumor cells before ribonucleic acid (RNA) extraction. RNA concentration and quality were measured using the NanoDrop ND-1000 spectrophotometer (NanoDrop Technologies). Microarrays were prepared and the integrity of total RNA was checked using an Agilent 2100 bioanalyzer (Agilent Technologies, Santa Clara, CA, USA) and data were acquired using Agilent’s G2565BA microarray scanner system.

In all, the team analyzed 322 genes involved in the immune system and after extensive screening; eight specific genes were identified as playing a significant role in glioblastoma multiforme. Three of the eight genes were shown to have a protective role, while the other five increased the risk of earlier death. The scientists were able to construct a genetic signature that predicted the survival times of the patients and divide them into low- and high-risk groups.

Even after controlling for factors such as treatment type, those in the high-risk genetic group were twice more likely to have a shorter survival time than those in the low-risk group. The high-risk group survived an average of 348 days after diagnosis while the low-risk group survived an average of 493 days. Those in the high-risk group were also likely to have a shorter time between diagnosis and the first signs that the tumor was becoming worse, 242 days compared with 369 for the lower-risk group. The study was published on May 25, 2016, in the journal Neurology.

Related Links:
First Hospital of China Medical University
NanoDrop Technologies
Agilent Technologies