title: Diagnosing xeroderma pigmentosum group C by immunohistochemistry.
abstract: Xeroderma pigmentosum (XP) is a group of rare inherited human neurocutaneous diseases, and the group C (XPC) is the major group of patients with XP in Europe, North America, and South America. Current molecular diagnostic methods for XP require specialized, expensive, and time-consuming UV sensitivity and DNA repair assays followed by gene sequencing. To determine whether immunohistochemistry (IHC) would be a robust alternative method to diagnose patients with XPC, we stained sections of paraffin-embedded skin biopsies for XPC by IHC, using 69 archived blocks from confirmed or clinically suspect patients with XPA, XPC, XPD, XPE, and without XP. We found that XPC expression was strong in all skin biopsies from patients without (14 of 14) and other patients with XP (4 of 4), whereas XPC expression was lost in all biopsies from confirmed XPC patients (29 of 29). Patches of strong XPC signal could be detected in sun-damaged skin, squamous and basal cell carcinomas from patients with XPC that colocalized with strong expression of p53 and Ki-67. Patients with XPC can therefore be diagnosed by IHC from paraffin-embedded skin biopsies from regions of skin that are without sun damage or sun-induced tumors. IHC is therefore a robust alternative method to diagnose patients with XPC. This fast and inexpensive method should increase the options for the diagnosis of patients with XPC from paraffin-embedded skin biopsies and could be developed for other complementation groups.
authors.affiliation: Department of Dermatology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: de Feraudy
authors.forename: Imenne
authors.initials: I
authors.lastname: Boubakour-Azzouz
authors.forename: Sylvie
authors.initials: S
authors.lastname: Fraitag
authors.forename: Mark
authors.initials: M
authors.lastname: Berneburg
authors.forename: Loretta
authors.initials: L
authors.lastname: Chan
authors.forename: Kevin
authors.initials: K
authors.lastname: Chew
authors.forename: Carol L
authors.initials: CL
authors.lastname: Clericuzio
authors.forename: Bari
authors.initials: B
authors.lastname: Cunningham
authors.forename: Whitney D
authors.initials: WD
authors.lastname: Tope
authors.forename: James E
authors.initials: JE
authors.lastname: Cleaver
mesh_terms: D001706:Biopsy; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D019394:Ki-67 Antigen / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism / Q000473:pathology; D016612:Paraffin Embedding; D012867:Skin / Q000378:metabolism / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014983:Xeroderma Pigmentosum / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology
chemical_list: D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53; C086984:XPC protein, human