Which of the following is NOT a type of cell adhesion molecule?

Lectins are proteins that primarily bind carbohydrates and are involved in various biological functions, such as cell signaling and immune responses. However, they are not classified as cell adhesion molecules like cadherins, selectins, and integrins.

Cadherins are a type of cell adhesion molecule that mediate calcium-dependent cell-cell adhesion, playing a crucial role in the formation of tissues and maintaining tissue architecture. Selectins facilitate the interaction between leukocytes and the endothelium during inflammation and immune responses. Integrins are versatile cell adhesion molecules that connect the cell's cytoskeleton to the extracellular matrix and are critical for cell signaling and communication.

In summary, while lectins play important roles in various biological processes, they do not fit into the category of cell adhesion molecules, making this the correct distinction.