Chromosomal instability and cellular hypersensitivity to X-radiation of cultured fibroblasts derived from porokeratosis patients' skin.

Porokeratosis is a rare genetic skin disorder known to be associated with a propensity to develop skin cancer. To further elucidate the previously reported cytogenetic and cellular abnormalities, we studied karyotypic changes and the sensitivity to X-ray irradiation of cultured fibroblasts derived from skin lesions and normal-appearing skin of 3 patients with porokeratosis. Cultured fibroblasts from normal-appearing skin of 9 controls were similarly examined. Porokeratosis subjects had a greater number of cells with chromosomal abnormalities than controls. Two porokeratosis strains which were derived from the normal-appearing skin of a patient had a noticeable clone of abnormal cells. Porokeratosis fibroblasts were hypersensitive to the lethal effects of X-radiation. This hypersensitivity was common to both the lesion-derived strains and the ones derived from normal-appearing skin. The 2 strains with clonal abnormal cells were also similarly hypersensitive to X-radiation. These results suggest that chromosomal instability is strongly related to porokeratosis and that X-ray hypersensitivity is an inherent abnormality in cultured fibroblasts of porokeratosis patients.