Stem-cell marker CD34, multidrug resistance proteins P-gp and BCRP in SEGA

Abstract

The resistance of human malignancy to multiple chemotherapeutic agents remains a major obstacle in cancer therapy due to in part to increased expression of ATP-binding cassette (ABC) transporters gene family, including “multidrug resistance 1”, and “breast cancer resistant protein”. These proteins are differentially expressed during normal hematopoiesis with the highest levels in primitive bone marrow CD34 stem cell population, and similarly, it was also suggested to occur transiently during neurulation. Subependymal Giant Cell Astrocytoma (SEGA) is a periventricular-low-grade tumor usually associated with tuberous sclerosis complex. We previously described that several multidrug-resistance proteins are overexpressed in brain cortical tubers associated with refractory epilepsy; however, they have not been investigated in SEGA. From a previous reported study of 15 brain specimens of SEGA, 6 randomized cases were selected for the immunostaining with specific monoclonal antibodies to multidrug resistance 1, breast cancer resistant protein and CD34 stem-cell marker. Heterogeneous distributions for these markers were detected with differential immunostaining pattern, showing high immunoreactivity in SEGA cells far of vessels, and low or negative expression in SEGA cells near the vessels. This particular expression pattern of both ABCtransporters, and CD34 antigen could identify different stem-cell subset in SEGA.