Which marker is most commonly used to identify endothelial cells in histology?

Which marker is most commonly used to identify endothelial cells in histology?

• A. CD31 (PECAM-1)
• B. von Willebrand factor
• C. CD34
• D. VE-cadherin

Answer: (A)

Endothelial cells are identified best when the marker used labels almost all vascular endothelia with clear, membranous staining across a wide range of vessels. CD31, also known as PECAM-1, fits this requirement well. It is a transmembrane glycoprotein located at endothelial cell junctions and is expressed broadly on endothelial cells throughout the vascular tree, giving strong, linear staining that outlines capillaries, venules, and arteries in tissue sections. This makes it a reliable and widely used marker for visualizing the vascular network in histology. Von Willebrand factor marks endothelial cells as well, but its presence is tied to Weibel-Palade bodies and can be variable in smaller vessels or certain tissues; it is also present in platelets, which can complicate interpretation in some samples. CD34 can stain endothelial cells, yet it is not entirely specific to endothelium since it also marks hematopoietic progenitors and other cell types. VE-cadherin is highly specific to endothelium and highlights adherens junctions, but practical staining can be more variable depending on tissue fixation and processing, so CD31 remains the most consistently reliable endothelial marker in routine histology. So, for clearly identifying endothelial lining across vessels in tissue sections, CD31 (PECAM-1) is the go-to marker.

Endothelial cells are identified best when the marker used labels almost all vascular endothelia with clear, membranous staining across a wide range of vessels. CD31, also known as PECAM-1, fits this requirement well. It is a transmembrane glycoprotein located at endothelial cell junctions and is expressed broadly on endothelial cells throughout the vascular tree, giving strong, linear staining that outlines capillaries, venules, and arteries in tissue sections. This makes it a reliable and widely used marker for visualizing the vascular network in histology.

Von Willebrand factor marks endothelial cells as well, but its presence is tied to Weibel-Palade bodies and can be variable in smaller vessels or certain tissues; it is also present in platelets, which can complicate interpretation in some samples. CD34 can stain endothelial cells, yet it is not entirely specific to endothelium since it also marks hematopoietic progenitors and other cell types. VE-cadherin is highly specific to endothelium and highlights adherens junctions, but practical staining can be more variable depending on tissue fixation and processing, so CD31 remains the most consistently reliable endothelial marker in routine histology.

So, for clearly identifying endothelial lining across vessels in tissue sections, CD31 (PECAM-1) is the go-to marker.