Figure 6: Proteins specifically expressed in squamous epithelia. Examples of proteins expressed in the group of squamous epithelia tissues. Several proteins found as specifically expressed in the group of squamous tissues are involved in squamous differentiation, cornification and desmosomal function. Examples shown include expression of SPINK5, known to be involved in hair formation, in the uppermost layer of normal skin (A). The interleukin 1 receptor antagonist IL1RN showed a distinct nuclear expression pattern in squamous epithelia that was restricted to basal cells, exemplified in normal esophagus (B). Cornulin (CRNN), suggested to play a role in squamous differentiation was expressed in suprabasal, differentiating squamous epithelia in the oral mucosa (C). The membrane bound hyaloronic acid receptor was found to be selectively expressed in all layers of squamous epithelia of the outer portions of the cervix (D).