title: Expression of JL1 is an effective adjunctive marker of leukemia cutis.
abstract: BACKGROUND
  Specific differentiation of leukemia cutis (LC) from nonleukemic dermatoses is crucial to ensure proper treatment for the disease. Because of the exceptionally variable histologic features of LC and the frequent nonleukemic dermatoses in leukemia patients, identification of leukemic cells that infiltrate skin lesions is important. Here, we introduce JL1, a novel leukemia-associated surface antigen, which is not expressed in mature human tissue but in cortical thymocytes and small subpopulations of bone marrow hematopoietic precursors.
  
  
  OBJECTIVE
  To assess the expression pattern of JL1 in LC and compare it with other commonly used markers. Also, to evaluate the expression of JL1 in other cutaneous lesions that need differential diagnoses.
  
  
  METHODS
  Immunohistochemical staining with anti-JL1 and other commonly used markers for LC was performed on paraffin-embedded skin biopsies from 32 cases of LC with acute lymphoblastic leukemia/lymphoma and acute myelogenous leukemia. Immunohistochemical staining score was evaluated in each case according to the proportion of positive tumor cells found. JL1 staining was also done on 96 reactive or neoplastic cutaneous lesions.
  
  
  RESULTS
  JL1 was detected in 7 of 11 acute lymphoblastic leukemia/lymphoma LC (63.6%) and 7 of 21 acute myelogenous leukemia LC (33.3%), with invariably high-staining scores. None of the other cutaneous lesions or normal tissues expressed JL1. The expression pattern of JL1 was not altered in 2 patients with follow-up biopsies.
  
  
  CONCLUSIONS
  Our finding that JL1 is expressed exclusively and stably by leukemic cells suggests that it can be used as a useful adjunctive marker for initial diagnosis and follow-up biopsy of LC, particularly in cases of scarce infiltrates.
authors.affiliation: Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Park
authors.forename: So Hyung
authors.initials: SH
authors.lastname: Park
authors.forename: Seo-Jeong
authors.initials: SJ
authors.lastname: Park
authors.forename: Youngji
authors.initials: Y
authors.lastname: Kim
authors.forename: Kee-Taek
authors.initials: KT
authors.lastname: Jang
authors.forename: Young Hyeh
authors.initials: YH
authors.lastname: Ko
authors.forename: Mi-Woo
authors.initials: MW
authors.lastname: Lee
authors.forename: Joo Ryung
authors.initials: JR
authors.lastname: Huh
authors.forename: Chan-Sik
authors.initials: CS
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000276:immunology*; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006086:Graft vs Host Disease / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D017254:Leukemic Infiltration / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012867:Skin / Q000276:immunology / Q000473:pathology; D012871:Skin Diseases / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D016463:Sweet Syndrome / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D055815:Young Adult
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D014408:Biomarkers, Tumor; C114952:JL1 antigen