title: Analysis of the Expression and Single-Nucleotide Variant Frequencies of the Butyrophilin-like 2 Gene in Patients With Uveal Melanoma.
abstract: OBJECTIVE
  Chromosome 6p amplification is associated with more benign behavior for uveal melanomas (UMs) with an otherwise high risk of metastasis conferred by chromosome 3 monosomy. Chromosome 6p contains several members of the B7 family of immune regulator genes, including butyrophilin-like 2 (BTNL2; OMIM, 606000), which is associated with prostate cancer risk and autoimmune diseases.
  
  
  OBJECTIVE
  To investigate the expression and variant allele frequencies of BTNL2, a candidate gene for chromosome 6 amplification, in patients with UM.
  
  
  METHODS
  In this case-control study, we analyzed the expression of BTNL2 in UM cell lines and human macrophages in patients with UM. Variants of BTNL2 were analyzed using probes for polymerase chain reaction and high-resolution melting. The association of missense variants rs28362679 and rs41441651 with tumor risk was analyzed in 209 patients with UM and 116 matched control patients as well as 12 UM and 64 other tumor cell lines. Genes that were differentially expressed in M1- and M2-polarized macrophages were identified by microarray analysis of 111 patients with UM, and the association of the expression of these genes with disease-free survival was analyzed by Cox regression analysis. Data were collected from September 2013 to November 2015.
  
  
  METHODS
  Butyrophilin-like 2 single-nucleotide variants were associated with UM risk; M1 and M2 macrophage-specific gene expression was associated with disease-free survival.
  
  
  RESULTS
  We genotyped a total of 325 patients. Of the 209 patients with UM, 124 (59.3%) were male, 114 (54.5%) were Italian, and 95 (45.5%) were German; the mean (range) age was 65 (27-94) years. Of the 116 Italian control patients, 67 (57.8%) were female, and the mean (range) age was 39 (21-88) years. Butyrophilin-like 2 is expressed in patients with UM and macrophages. The frequency of the rs28362679 variant was higher in patients with UM (16 of 209 [7.7%]; 95% CI, 4.7-12.2) than frequencies from European Variation Archive and Exome Aggregation Consortium data (2134 of 118 564 [1.8%]; 95% CI, 1.7-1.9) and Exome Sequencing Project data (100 of 4540 [2.2%]; 95% CI, 1.8-2.7) but were not higher compared with Italian control patients (10 of 116 [8.6%]; 95% CI, 4.6-15.4). The rs41441651 variant was present in 5 patients with UM (2.4%; 95% CI, 0.9-5.7), 2 Italian control patients (1.7%; 95% CI, 0.1-6.5), 2846 patients from European Variation Archive and Exome Aggregation Consortium data (2.4%; 95% CI, 2.3-2.5), and 23 patients from Exome Sequencing Project data (0.5%; 95% CI, 0.3-0.8). Human UM cells express M1 and M2 macrophage-specific genes, whose expression is associated with disease-free survival.
  
  
  CONCLUSIONS
  Butyrophilin-like 2, expressed at various levels by UM cells and macrophages, might interfere with the immune control of the tumor. Butyrophilin-like 2 variants showed highly variable frequencies among ethnically related cohorts. There was no enrichment of BTNL2 variants in patients with UM compared with control patients.
authors.affiliation: Laboratory of Molecular Pathology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy2Department of Earth Sciences, Environment, and Life, Università Degli Studi di Genova, Genova, Italy.
authors.forename: Adriana
authors.initials: A
authors.lastname: Amaro
authors.affiliation: Laboratory of Molecular Pathology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy3Intergruppo Melanoma Italiano, Genova, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Parodi
authors.affiliation: Laboratory of Molecular Pathology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Konrad
authors.initials: K
authors.lastname: Diedrich
authors.affiliation: Laboratory of Molecular Pathology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Angelini
authors.affiliation: TIB-Molbiol Syntheselabor, Berlin, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Götz
authors.affiliation: Department of Earth Sciences, Environment, and Life, Università Degli Studi di Genova, Genova, Italy5Ente Ospedaliero Galliera, Genova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Viaggi
authors.affiliation: Ente Ospedaliero Galliera, Genova, Italy.
authors.forename: Irena
authors.initials: I
authors.lastname: Maric
authors.affiliation: Ente Ospedaliero Galliera, Genova, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Coviello
authors.affiliation: Department of Tumor Epigenetics, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Pistillo
authors.affiliation: Department of Tumor Epigenetics, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Morabito
authors.affiliation: Azienda Socio Sanitaria Territoriale Ospedale Papa Giovanni XXIII, Bergamo, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Mandalà
authors.affiliation: Department of Genetics of Rare Tumors, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Ghiorzo
authors.affiliation: Department of Blood Transfusion Center, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Visconti
authors.affiliation: Department of Anatomy and Cytohistopathology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Gualco
authors.affiliation: Ospedale Villa Scassi, Genova, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Anselmi
authors.affiliation: Department of Clinical Epidemiology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Puzone
authors.affiliation: Ente Ospedaliero Galliera, Genova, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lanza
authors.affiliation: Ente Ospedaliero Galliera, Genova, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Mosci
authors.affiliation: Laboratory of Molecular Biology, Istituto Giannina Gaslini, Genova, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Raggi
authors.affiliation: Laboratory of Molecular Biology, Istituto Giannina Gaslini, Genova, Italy.
authors.forename: Maria Carla
authors.initials: MC
authors.lastname: Bosco
authors.affiliation: Laboratory of Molecular Biology, Istituto Giannina Gaslini, Genova, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Varesio
authors.affiliation: Institute of Human Genetics, Faculty of Medicine, University Duisburg-Essen, West German Cancer Center and the German Cancer Consortium, Essen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Zeschnigk
authors.affiliation: Department of Medical Oncology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Spano
authors.affiliation: Department of Medical Oncology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Queirolo
authors.affiliation: Laboratory of Molecular Pathology, Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pfeffer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000071797:Butyrophilins / Q000096:biosynthesis / Q000235:genetics*; D045744:Cell Line, Tumor; D004273:DNA, Neoplasm / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D012189:Retrospective Studies; D014604:Uveal Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D000098943:Uveal Melanoma
chemical_list: C408263:BTNL2 protein, human; D000071797:Butyrophilins; D004273:DNA, Neoplasm