homotypic

Homotypic is an adjective used in biology and related fields to describe interactions, processes, or structures involving entities of the same type. The term derives from Greek homo- meaning “same” and typos meaning “type.” In practice, homotypic use highlights sameness in the interacting participants or components.

In cell biology, homotypic interactions describe adhesion or signaling between cells of the same type. A primary example is homophilic cell adhesion, where cadherins on the surface of one cell bind to the same type of cadherin on an adjacent cell, promoting tissue integrity and cell sorting during development. Homotypic protein–protein interactions can also refer to binding between identical proteins or identical domains on different molecules.

In histopathology and developmental biology, homotypic can describe tissues or tumors that resemble the normal cells of the same lineage, displaying a uniform (homotypic) differentiation pattern rather than diverse (heterotypic) differentiation.

By contrast, heterotypic refers to interactions or relationships between different cell types or tissues, such as epithelial–stromal signaling. The distinction between homotypic and heterotypic is used to describe mechanisms of tissue organization, cell sorting, and differentiation in development, cancer biology, and tissue engineering.

Note: usage can vary by field, and some contexts may emphasize identical components or domains rather than strictly identical cell types.