Related Experiment Video
Updated: Aug 18, 2026

The Three-Dimensional Human Skin Reconstruct Model: a Tool to Study Normal Skin and Melanoma Progression
Published on: August 3, 2011
Expression of ras proto-oncogene related protein p21 in normal human skin and cutaneous tumours
E Tanikawa1, O Mori, H Hachisuka
1Department of Dermatology, Kurume University School of Medicine, Japan.
Abstract:
The cellular proto-oncogene, ras, is known to play an important role in the regulation of cell growth and proliferation in normal and malignant conditions. The present study was undertaken to immunohistochemically examine the expression of ras protooncogene product p21 in normal human skin and some cutaneous tumours. In normal skin, the expression of p21 was found in sweat glands, sebaceous glands, capillary endothelium, and smooth muscles, while epidermis was devoid of reaction product. Keratoacanthoma and the granular cells of verruca vulgaris were immunoreactive to the antibody for p21. Bowen's disease and squamous cell carcinoma were positive for p21, but basal cell carcinoma and seborrheic keratosis were negative. In mammary and extramammary Paget's diseases, the immunoreactivity was inconsistent. The expression of p21 in malignant melanoma cells was intense, whereas normal melanocytes and nevus cells were devoid of the expression. These results suggest that the expression of p21 does not correlate with nuclear anaplasia and malignant behaviour of cutaneous tumours.
Related Concept Videos
Negative Regulator Molecules
Abnormal Proliferation
Cancer-Critical Genes I: Proto-oncogenes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
The Ras Gene
Ras is a superfamily...
The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:

