Chromosome abnormalities of porokeratosis-cultured epidermal keratinocytes. Comparison with those of cultured dermal fibroblasts.

Cultured epidermal keratinocytes and dermal fibroblasts derived from porokeratosis (PK) patients' skin lesions or normal-appearing skin had numerical and sometimes structural chromosomal abnormalities. Such abnormal cells were seen in 4.08% and 0.375% of all the studied epidermal keratinocytes derived from affected skin and normal-appearing skin, respectively. Similar abnormalities were present in 1.70% and 3.67% of the dermal fibroblasts from the patients' affected skin and normal-appearing skin, respectively. Chromosomal abnormalities were more frequent in keratinocytes and fibroblasts from the patients' skin than in keratinocytes (0.429%) or in fibroblasts (1.22%) derived from normal control donors. Clonal proliferation of such abnormal cells was frequently seen in keratinocytes from the patients' affected skin. The frequent appearance of chromosomal abnormalities and clonal proliferation in epidermal keratinocytes may explain skin lesion formation and skin cancer development in PK patients.