Abstract

BACKGROUND
This study is aimed to elucidate the developmental pattern of human fetal lip by histological and immunohistochemical examinations.
METHODS
Totally 231 normal human lip tissues obtained from autopsied fetuses were fixed with 10% buffered formalin, sectioned in cross and longitudinal directions, routinely stained for H&E and performed for immunohistochemistry with antibodies of S-100 protein, proliferating cell nuclear antigen (PCNA), transglutaminase C (TGase-C), metalloproteinase (MMP)-3, MMP-10, tenascin, KL1, K8.12, E-cadherin, tissue inhibitors of matrix metalloproteinase (TIMP)-1, TIMP-2 and total keratin (TK).
RESULTS
The lip structure first appeared as an orifice of stomodeum around the 7-8th week of gestation, and a major structure of the midface was observed by the 11-12th week. As the squamous epithelium of the lip became thick and was keratinized, the vermilion border became distinguished in the 15-16th week, and the lip structure was almost completed with the presence of orbicularis oris muscle in the lingual side of vermilion border by the 17-18th week. Immunohistochemically, the vermilion border showed strong reactions for tenascin, E-cadherin and MMP-3 and increased positivity for PCNA, cytokeratins (TK, KL1, K8.12), and TGase-C.
CONCLUSIONS
With the above findings we suppose that the cytodifferentiation of vermilion border epithelium plays an important role for the development of human fetal lip.

• Keywords: Fetal Development-Lip-Immunohistochemistry