Abstract

BACKGROUND
During the fetal stage, the epidermis and adnexal epithelium might express different types of cytokeratin (CK) by developmental stages. The objective of this study is to observe the expressions of CK1, CK10 and CK14 in the skin of human fetuses.
METHODS
Immunohistochemical stains were applied to the skin of 42 fetuses ranging from 10 to 36 gestation weeks. Three different portions of the body (i.e., scalp, chest and sole) were sampled. Immunohistochemical staining with monoclonal antibodies against CK1, 10, 14 were done.
RESULTS
We found that CK14 was expressed in the basal layer of the epidermis and adnexae of fetuses beween 10 to 36 gestation weeks. However, stronger expression in the middle than the basal layer was noted in the soles of 15-week fetuses followed by exclusive basal expression. The sebaceous gland, the outer root sheath of the hair follicle and the eccrine duct epithelium also showed CK14 expressions, while CK14 was negative in hair germ and acini. Both CK1 and CK10 were expressed in the epidermis of fetuses ranging between 10 to 36 gestation weeks at the suprabasal layer of the scalp, chest and sole; while they were negative in the basal layer and skin adnexae including sebaceous, hair and eccrine gland.
CONCLUSIONS
Expression of cytokeratins in the fetal skin were noted at 10 weeks throughout the entire gestation period and were similar in the three different sites, except in the early stage of the sole. The main expression sites of K14 were the basal layer of the epidermis, the eccrine ducts and the outer root sheath cells of hair, suggesting the same origin, while those of K1 and K10 were in the suprabasal layer of epidermis.

• Keywords: Keratin;Fetus;Skin;Development;