Similar to other parts of the body, the brain is susceptible to tumor growth. More than 200,000 Americans are diagnosed with brain tumors each year. Only about 20 percent of cases, however, involve primary tumors, which initiate from abnormal brain cells. Metastatic tumors that spread to the brain from other regions of the body account for the rest of the diagnoses. More than 100 different types of brain tumors are recognized, some of which are malignant and some of which are benign. Because of the importance of brain function to the rest of the body and the very limited amount of space in the cranium, even those tumors that are benign can be extremely injurious or even life threatening.

Immunofluorescence was utilized to target the blood brain barrier (BBB) and astroglia in a sagittal section of rat brain tissue. First, the specimen was fixed, permeabilized, blocked with 10-percent normal goat serum, and treated with a cocktail of mouse anti-BBB and rabbit anti-GFAP primary antibodies. Then, to visualize the primary targets, the tissue section was treated with goat anti-mouse and anti-rabbit secondary antibodies (IgG) conjugated to Alexa Fluor 568 and Alexa Fluor 488, respectively. Finally, cell nuclei were labeled with Hoechst 33342. Images were recorded in grayscale with a 12-bit digital camera coupled to a Nikon Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.