The relationship of Ki67 and involucrin expression in proliferative, pre-neoplastic and neoplastic skin

Abstract

In normal skin, proliferation and differentiation are tightly coupled in order to maintain normal architecture in a continually renewing tissue. The temporal and spatial relationships between these two processes in normal, psoriatic, pre-neoplastic and neoplastic skin were investigated by a double immunolabelling technique with Ki67 as a marker of proliferation and involucrin as a marker of terminal differentiation. In normal skin, expression of the two antigens was strictly spatially segregated. In the abnormal, the proportions of cells expressing the antigens were increased with some loss of the spatial segregation, while small numbers of cells showed dual expression suggesting loss of the normal control between proliferation and differentiation. However, the quantitative ratio of proliferation to differentiation in psoriatic and pre-neoplastic skin was similar to the normal; transition to an invasive phenotype, however, was associated with a reversal of this ratio, and this correlated well with the degree of histological differentiation.

Occludin Is Involved in Adhesion, Apoptosis, Differentiation and Ca2+-Homeostasis of Human Keratinocytes: Implications for Tumorigenesis

“…Accordingly, irregularity of epidermal differentiation markers involucrin and TG1 was described in SCC [38], [39], [40]. Therefore we investigated whether downregulation of Ocln may influence epidermal differentiation.…”

“…Several studies described a downregulation of involucrin in poorly differentiated SCC, while it was strongly expressed in highly differentiated SCC [38], [39], [40], [44]. For TG1 increased staining intensity was described in the epidermal part of cutaneous SCC, [41], a frequent (69%) upregulation was also observed in SCC of the lung [57].…”

“…It can be categorized in well, moderately and poorly differentiated SCCs [36], [37]. Epidermal differentiation marker involucrin was described to be present in lower malignant, well differentiated SCCs but to be decreased in higher malignant, poorly differentiated ones [38], [39], [40], Transglutaminase 1 (TG1) was described to be increased in the epidermal part of the SCCs but is absent in invasive parts [41]. Actinic keratoses (AK) and Bowen’s disease (BD) are suggested to be precursors (c arcinomata in situ ) of SCC and their presence is a marker for increased risk for the occurrence of SCC [42].…”

E6/E7 Expression of Human Papillomavirus Type 20 (HPV-20) and HPV-27 Influences Proliferation and Differentiation of the Skin in UV-Irradiated SKH-hr1 Transgenic Mice

“…Proliferation and differentiation are coupled and spatially segregated in the normal epidermis. A disturbance in this control may be correlated with an invasive phenotype (9). Expression of both involucrin and loricrin was reduced and disturbed by the expression of the viral E6 and E7 genes in the presence of UV-B irradiation.…”

Correlation Between Macroscopic Fluorescence and Protoporphyrin IX Content in Psoriasis and Actinic Keratosis Following Application of Aminolevulinic Acid

“…In non-involved psoriatic skin, this percentage of cells in S-phase was 3.8%. To the best of our knowledge, in AK, these exact percentages are not known but when proliferation indices (PI) of psoriasis and AK were compared (using Ki-67 expression) in a study of Caldwell et al (1997) AK appeared to have a PI that is 1.26 times the PI in psoriasis. This means that in our samples, dsDNA values as a marker of the total number of epidermal keratinocytes could be overestimated.…”