A young woman with xeroderma pigmentosum complementation group F and a morphoeic basal cell carcinoma.

We report an 18-year-old Japanese woman who had mild photosensitivity and a facial tumour, which was shown to be a morphoeic basal cell carcinoma. Although a line of fibroblasts derived from the patient, Kps6 cells, were slightly more sensitive to UV irradiation than normal cells, their level of unscheduled DNA synthesis was about 20% that of normal cells, and recovery of RNA synthesis after UV irradiation was moderately depressed. Complementation tests, carried out by cell fusion or by microinjection of plasmids harbouring xeroderma pigmentosum (XP) genes, indicated that the patient had XP group F. To our knowledge, this is the youngest XP group F patient with a malignant tumour reported to date.