Stains for Nissl substance can be used to identify the presence of neurons in tumor tissue.

• A. True
• B. False
• C. Only glial cells are stained
• D. They stain lipids

Answer: (A)

Nissl staining targets the rough endoplasmic reticulum in neuronal cell bodies, producing the characteristic Nissl substance. Because neurons have abundant ribosomes and RNA in their soma, they take up the stain strongly and appear as clearly defined, basophilic cell bodies. Glial cells contain far less Nissl substance, so they’re less stained. This difference lets you identify neurons within tissue sections, including tumor tissue, where neuronal differentiation or components may be present.

In practical terms, if a tumor contains neuronal cells, those cells will typically show Nissl-positive staining of their somata, helping distinguish neurons from glial elements. Nissl stains highlight cell bodies but not lipid-rich areas or myelin, and they don’t stain neuronal processes like axons or dendrites. That’s why the presence of Nissl-positive neurons in a tumor indicates neuronal components, making the statement true.