Immunofluorescent stain of SF767 (human glioma cell line). Immunofluorescence is a technique used for light microscopy with a fluorescence microscope and is used primarily on microbiological samples. A glioma is a type of tumor that starts in the brain or spine. It is called a glioma because it arises from glial cells. The most common site of gliomas is the brain. Gliomas make up about 30% of all brain and central nervous system tumors and 80% of all malignant brain tumors. The laboratory technique of maintaining live cell lines (a population of cells derived from a single cell and containing the same genetic makeup) separated from their original tissue source became more robust in the middle 20th century.