Although the population of oral melanocytes appears to remain more or less constant throughout life, the mechanisms for their replacement in the basal cell layer
of the epithelium after loss to physiological processes of apoptosis, or to mechanical, thermal, or chemical injury, are not well understood.
Malignant glands do not express GSTP1 at all, and they are completely negative due to the lack of the basal cell layer
(Figures 1 and 2).
p53 expression above the basal cell layer
in oral mucosa is an early event of malignant transformation and has predictive value for developing oral squamous cell carcinoma.
This mixture of yeasts, hyphae, and matrix material is not seen when the organism is grown in liquid culture or on an agar surface, which suggests that morphogenesis is triggered when an organism contacts a surface and that the basal cell layer
may have an important role in anchoring the biofilm to the surface (2,3,5,8).
This assumption is based on findings in the rabbit primary culture system which showed that for the urothelium to achieve maximal differentiation (from an undifferentiated basal cell layer
to a high resistance apical umbrella cell layer) required growth of the cells on a permeable support, careful attention to seeding densities, and manipulation of the calcium concentration of the growth medium (29).
Approximately 3% of radiation below 300nm, 20% of radiation below 360nm and 33% of short visible radiation reaches the basal cell layer
in non-tanned human skin.
In normal epithelium, there is continuous renewal of cells by the mitotic division at the basal cell layer
. These cell migrate to the surface of the epithelium to replace the cells that are shed.
These central zone glands may occasionally display early cribriform architectural pattern (Figure 2, D), but, similar to benign cribriform hyperplasia, the cribriform central zone glands lack cytologic atypia or prominent nucleolus, and often show a very prominent basal cell layer
. Central zone glands may show lipofuscin pigment, as seen in seminal vesicle epithelium.
The presence of a single cell lining with complete absence of the basal cell layer
In all control specimens, an abundance of PAX9-positive cells was seen in the oral epithelium, especially in the basal cell layer
Cutaneous malignant melanoma arises from the melanocytes within the basal cell layer
of the epidermis (Lorimer, D.
The epidermis itself has four layers: the stratum corneum, the granular layer, the squamous cell layer and the basal cell layer
. Keratin (dead, dense protein cells) makes up the stratum corneum or outer layer of the epidermis--the skin layer that can be seen and felt.