title: Hereditary dysplastic nevus syndrome: lymphoid cell ultraviolet hypermutability in association with increased melanoma susceptibility.
abstract: The hereditary dysplastic nevus syndrome (DNS) is a well-characterized disorder in which affected individuals have increased numbers of premalignant (dysplastic) nevi and a markedly increased risk of developing cutaneous melanoma. Seeking evidence of a systemic disorder in DNS, we examined the effect of ultraviolet radiation on cultured lymphoid cells. Epstein-Barr virus-transformed lymphoblastoid cell lines from patients with hereditary DNS had similar survival values following treatment with 2.3 to 9.0 J of 254-nm ultraviolet radiation per m2 as did lines from control individuals. Mutagenesis at the hypoxanthineguanine phosphoribosyltransferase locus was assessed by measuring the induction of resistance to thioguanine using a microtiter well assay. Three lymphoblastoid cell lines from patients with hereditary DNS and melanoma had a 2- to 3-fold greater frequency of induced mutants per clonable cell than three normal lines following exposure to 4.5 to 9.0 J of ultraviolet radiation per m2. Expanded clones of mutated DNS lymphoblastoid cell lines had less than 6% of normal hypoxanthine-guanine phosphoribosyltransferase activity. Inhibition and recovery of DNA synthesis following ultraviolet exposure were similar in 2 DNS and 2 normal lines. Repair by DNS lines of ultraviolet-induced DNA damage was in the normal range as measured by alkaline elution. Thus, hereditary DNS exhibits in vitro hypermutability which may reflect increased susceptibility to ultraviolet-induced somatic mutations in vivo. This abnormality may be related to the increased melanoma susceptibility of patients with hereditary DNS.
mesh_terms: D000328:Adult; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004260:DNA Repair; D005260:Female; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D008214:Lymphocytes / Q000528:radiation effects; D008297:Male; D008545:Melanoma / Q000209:etiology* / Q000235:genetics; D009154:Mutation / Q000528:radiation effects; D009506:Nevus / Q000150:complications / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D004247:DNA; D007041:Hypoxanthine Phosphoribosyltransferase