The symptoms of brain tumors vary and are chiefly dependent on the size and location of the abnormal growth. For example, a tumor located in the occipital lobe might interfere with vision, whereas a tumor in the parietal lobe would be more likely to produce speech abnormalities. More general problems, such as headaches, nausea, vomiting, and seizures may develop most anywhere a tumor develops in the brain if it becomes large enough due to increased cranial pressure. Tumor growth in the brain can also result in a build-up of cerebrospinal fluid in the ventricular system, leading to hydrocephalus.

Myelin was targeted in the sagittal rat brain section presented above with mouse anti-myelin CNPase antibodies followed by goat anti-mouse secondary antibodies conjugated to Alexa Fluor 488. In addition, glial fibrillary acidic protein was targeted in the tissue section by treating the specimen with rabbit anti-GFAP antibodies visualized with goat anti-rabbit secondary antibodies conjugated to Alexa Fluor 568. Nuclear DNA was counterstained 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.