Blood-vessel-forming Cells Increase in Aggressive Brain Tumor

Targeting cells involved in the formation of new blood vessels (endothelial progenitor cells-EPC) could hinder tumor growth of a highly malignant brain tumor (astrocytomas), reveals a new research published in the Pertanika Journal of Science & Technology. They found that the number of EPCs was higher in the tumors, which has increased with age and with higher tumor grade than surrounding healthy tissue.

EPCs are circulating cells that participate in new blood vessel formation and adhere to the inner linings of blood vessels.

Astrocytomas

Astrocytomas are the most common primary brain and spinal cord tumors that originate from a type of cell called an astrocyte. Astrocytes insulate and provide structure for nerve fibers. They can occur in both adults and children. They can be low grade (slow growing) or high grade/malignant (fast-growing) and are named grades I to IV according to their aggressiveness.

Among the four grades of astrocytomas, grade IV astrocytomas are the most aggressive; they are highly invasive and almost always fatal. Another important fact to note is that the astrocytomas with lower aggression are typically found in younger people while those tumors that are more aggressive are more often seen in older adults.

Astrocytomas depend on new blood vessel formation to grow and spread; in other words, they rely upon EPCs to proliferate.

In Malaysia, the research team investigated the association between EPCs that were present in brain tumor tissues and the ones in normal adjacent tissues in relation with age and grade of astrocytomas.

Did EPCs change with Increasing Grades of Astrocytomas?

The team of scientists obtained brain tumor tissue and normal adjacent brain tissue samples during surgery from 22 astrocytoma patients with grade I to grade IV tumors at the Hospital of University Sains Malaysia. The severity of the disease in the patients increased as they got older.

Compared to the surrounding healthy tissue, the numbers of EPCs inside the tumor tissues were higher and increased with age and with higher tumor grade.

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Earlier studies have shown that

• Patients with grades III and IV astrocytomas who underwent radiotherapy or chemotherapy showed a reduction in the number of circulating EPCs
• Grades III and IV astrocytoma patients who did not undergo treatment had higher numbers of circulating EPCs than healthy people
• Significantly reducing EPCs led to impaired and delayed growth in tumors which was followed by a reduction in the number of blood vessels feeding them

The research team concluded that astrocytoma growth could be prevented by giving appropriate drug doses targeting the new blood vessel forming cells, according to age and tumor grade.
 
References:

1. Priscilla Das, Nyi Nyi Naing, Nadiah Wan-Arfah, KON Noorjan, Yee Cheng Kueh and Kantha Rasalingam., “Increased Endothelial Progenitor Cells with Age and Grade of Malignancy in Astrocytic Glioma Patients” (2018) Science & Technology.
2. Yoder MC. Human Endothelial Progenitor Cells. Cold Spring Harbor Perspectives in Medicine. 2012;2(7):a006692. doi:10.1101/cshperspect.a006692.
3. Glioma in adults - (http://www.cancerresearchuk.org/about-cancer/brain-tumours/types/glioma-adults)

Source-Medindia