Expression of individual lamins in basal cell carcinomas of the skin

In this study we used a unique collection of type specific anti-lamin antib odies to study iamin expression patterns in normal human skin and in skin d erived from patients with basal cell carcinomas (BCCs). Lamin expression in serial sections from frozen tissue samples was investigated by single and double indirect immunofluorescence. In normal skin, lamin A was expressed i n dermal fibroblasts and in suprabasal epithelial cells but was absent from all basal epithelial cells. Lamin C was expressed in dermal fibroblasts, s uprabasal epithelial cells and a majority of basal epithelial cells. Howeve r, lamin C was not expressed in quiescent basal epithelial cells. Lamin B-1 was expressed in all epithelial cells but was not expressed in dermal fibr oblasts. Finally, lamin B-2 was expressed in all epithelial cells but was n ot expressed in dermal fibroblasts. Finally, lamin B-2 was expressed in all cell types in normal skin. Lamin expression was also investigated in a col lection of 16 BCCs taken from a variety of body sites, Based upon patterns of lamin expression the BCCs were classified into four groups: A-negative ( 10/16 rumours), C-negative (5/16 tumours), A/C-negative (1/16 tumours) and A/B-2-negative (1/16 tumours). Lamin expression was also compared to cell p roliferation index by staining serial sections with the proliferation marke r Ki67. 9/10 of the lamin A negative tumours were highly proliferative, whe reas 4/5 of the iamin C negative tumours were slow growing. Thus as a gener al rule absence of lamin A was correlated with rapid growth within the tumo ur, while absence of lamin C was correlated with slow growth within the tum our. Our data supports the hypothesis that lamin A has a negative influence on cell proliferation and its down regulation may be a requisite of tumour progression. (C) 2001 Cancer Research Campaign.