Multi-omics analysis of the expression and prognostic value of the butyrophilins in breast cancer.

Butyrophilins (BTNs) belong to the immunoglobulin superfamily of transmembrane proteins and play a role in the regulation of lymphocyte activation, several autoimmune diseases, and the progression of human cancers. However, the associated clinicopathologic characteristics and prognostic value of BTNs in breast cancer remain unknown. This study aimed to discover potential key related BTN genes and signaling pathways in breast cancer, which could provide new insights for immune-based strategies. In the present study, the mRNA expression level and prognostic value of BTN2A1, BTN3A1, BTN3A2, BTN3A3, BTNL2, BTNL9, ERMAP, and MOG were measured. Up-regulation of these genes was significantly correlated with improved overall and relapse-free survival. We then analyzed the prognostic outcomes of breast cancer subtypes, genetic alterations, interaction networks, and the functional enrichment of eight BTN family genes. Our results showed that these eight genes played essential roles in tumor progression. Furthermore, an immune infiltration analysis indicated that most candidate BTN family members were associated with intratumoral immune cell infiltration, especially that of γδ T cells. Finally, gene set enrichment analysis for a single hub gene revealed that each BTN gene played a vital role in tumor progression through immune signaling pathways. These findings provided new insights into breast cancer pathogenesis and identified eight potential biomarkers for breast cancer.

Butyrophilin-Like 9 (BTNL9) Suppresses Invasion and Correlates with Favorable Prognosis of Uveal Melanoma.

BACKGROUND Uveal melanoma (UM) is the most common intraocular malignancy, and the prognosis of patients with advanced stage of UM is very dismal. The T cell receptor ectopic expression of butyrophilin-like 9 (BTNL9) has been observed in several types of cancers, but the expression and clinical significance of BTNL9 in UM is unclear. MATERIAL AND METHODS In our study, we detected the expression of BTNL9 in 6 pairs of UM tissues and adjacent tissues using quantitative real-time polymerase chain reaction (qRT-PCR), and further investigated BTNL9 expression with immunohistochemistry (IHC) in a retrospective cohort consisted of 62 UM patients. The correlations between BNTL9 expression and clinicopathological factors were analyzed with Fisher's test, and the prognostic significance of BTNL9 was evaluated with univariate analysis and multivariate analysis. Using experiments in vitro, we investigated the function of BTNL9 in UM proliferation and invasion. RESULTS BTNL9 mRNAs in adjacent tissues were remarkably higher than in UM tissues. The percentages of BTNL9 low expression and high expression were 56.45% and 43.55%, respectively. High expression of BTNL9 was significantly associated with favorable prognosis of UM. BTNL9 expression was identified as a prognostic biomarker predicting better outcome of UM patients. Moreover, BTNL9 could suppress invasion instead of proliferation in melanoma cell line. CONCLUSIONS BTNL9 was a favorable prognostic factor of UM and it could suppress invasion of UM, suggesting that BTNL9 detection could help stratify high-risk patients with UM after operation and guide more precise surveillance and treatment.

Expression QTL analysis of glaucoma endophenotypes in the Norfolk Island isolate provides evidence that immune-related genes are associated with optic disc size.

Primary open-angle glaucoma (POAG) is influenced by both genetic and environmental factors. Despite significant progress in identifying genetic variants associated with POAG, there remains a substantial amount of unexplained heritability. Study design features that may enhance knowledge of the genetic architecture include focusing on multiple quantitative traits related to ocular disorders (i.e. endophenotypes), targeting genetic variants that directly influence gene expression (i.e. cis-eQTLs) and utilising genetically isolated populations to reduce genetic and environmental noise and thus enhance association signals. In this study we performed heritability and blood-based eQTL association analysis of five key POAG endophenotypes in 330 individuals from the Norfolk Island (NI) isolate. Results showed evidence of heritability for all five traits, with H2 estimates ranging from 0.35 for intraocular pressure (IOP) to 0.82 for central corneal thickness (CCT) (P < 0.05). The primary finding was for BTN3A2, whereby both cis-SNP and transcript were significantly associated with disc size within a conditional regression model. Specifically, this model included rs853676 (ß = 0.23,P = 0.008) and transcript (ß = 0.23, P = 0.03). We also observed a cis-SNP association between optic disc size and LPCAT2 independent of transcript (P = 0.0004). These genes have specific functions in immune system pathways and suggest a role for an inherited immune component of POAG risk. This study also demonstrates an alternate approach to understanding the functional genetic basis of POAG and ocular health more generally.

Analysis of the Expression and Single-Nucleotide Variant Frequencies of the Butyrophilin-like 2 Gene in Patients With Uveal Melanoma.

IMPORTANCE: 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. DESIGN, SETTING, AND PARTICIPANTS: 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. MAIN OUTCOMES AND MEASURES: 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 AND RELEVANCE: 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.