title: LGR5 is associated with tumor aggressiveness in papillary thyroid cancer.
abstract: OBJECTIVE
  Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is a cancer stem cell marker and a down-stream target in Wnt/β-catenin signaling. In human papillary thyroid cancer (PTC), over activation of Wnt/β-catenin has been associated with tumor aggressiveness.
  
  
  METHODS
  Using established human cell lines (TPC-1, KTC-1, Nthy-ori-3-1), we report LGR5 and R-spondin (RSPO1-3) overexpression in PTC and manipulate LGR5 and Wnt/β-catenin signaling via both pharmacologic and genetic interventions. We test the association of LGR5 tumor expression with markers of PTC aggressiveness using a Discovery Cohort (n = 26 patients) and a Validation Cohort (n = 157 patients). Lastly, we explore the association between LGR5 and the BRAFV600E mutation (n = 33 patients).
  
  
  RESULTS
  Our results reveal that LGR5 and its ligand, RSPO, are overexpressed in human PTC, whereby Wnt/β-catenin signaling regulates LGR5 expression and promotes cellular migration. In two separate cohorts of patients, LGR5 and RSPO2 were associated with markers of tumor aggressiveness including: lymph node metastases, vascular invasion, increased tumor size, aggressive histology, advanced AJCC TNM stage, microscopic extra thyroidal extension, capsular invasion, and macroscopic invasion. As a biomarker, LGR5 positivity predicts lymph node metastasis with 95.5% sensitivity (95% CI 88.8%-98.7%) and 61% specificity (95% CI: 48.4%-72.4%) and has a negative predictive value (NPV) of 91.3% (95% CI 79.2%-97.5%) for lymph node metastatic disease. In human PTC, LGR5 is also strongly associated with the BRAFV600E mutation (p = 0.005).
  
  
  CONCLUSIONS
  We conclude that overexpression of LGR5 is associated with markers of tumor aggressiveness in human PTC. LGR5 may serve as a future potential biomarker for patient risk stratification and loco regional metastases in PTC.
authors.affiliation: Division of Gastroenterology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Michelotti
authors.affiliation: Department of Pathology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Xiaoyin
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Julie Ann
authors.initials: JA
authors.lastname: Sosa
authors.affiliation: Division of Gastroenterology, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Anna Mae
authors.initials: AM
authors.lastname: Diehl
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Wake Forest University, Winston-Salem, North Carolina, USA.
authors.forename: Brittany Bohinc
authors.initials: BB
authors.lastname: Henderson
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002291:Carcinoma, Papillary; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D012680:Sensitivity and Specificity; D019699:Thrombospondins / Q000096:biosynthesis; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D060449:Wnt Signaling Pathway / Q000502:physiology; D051176:beta Catenin / Q000378:metabolism; D000098907:R-Spondins
chemical_list: D014408:Biomarkers, Tumor; D048493:Proto-Oncogene Proteins B-raf; D043562:Receptors, G-Protein-Coupled; D019699:Thrombospondins; D051176:beta Catenin; C116884:LGR5 protein, human; C503243:RSPO1 protein, human; D000098907:R-Spondins; C482119:BRAF protein, human
keywords: BRAFV600E; R-spondin; Wnt; metastasis; β-catenin