title: Exploring Glycan Markers for Immunotyping and Precision-targeting of Breast Circulating Tumor Cells.
abstract: OBJECTIVE
  Recognition of abnormal glycosylation in virtually every cancer type has raised great interest in exploration of the tumor glycome for biomarker discovery. Identifying glycan markers of circulating tumor cells (CTCs) represents a new development in tumor biomarker discovery. The aim of this study was to establish an experimental approach to enable rapid screening of CTCs for glycan marker identification and characterization.
  
  
  METHODS
  We applied carbohydrate microarrays and a high-speed fiber-optic array scanning technology (FAST scan) to explore potential glycan markers of breast CTCs (bCTCs) and targeting antibodies. An anti-tumor monoclonal antibody, HAE3-C1 (C1), was identified as a key immunological probe in this study.
  
  
  RESULTS
  In our carbohydrate microarray analysis, C1 was found to be highly specific for an O-glycan cryptic epitope, gp(C1). Using FAST-scan technology, we established a procedure to quantify expression levels of gp(C1) in tumor cells. In blood samples from five stage IV metastatic breast cancer patients, the gp(C1) positive CTCs were detected in all subjects; ∼40% of bCTCs were strongly gp(C1) positive. Interestingly, CTCs from a triple-negative breast cancer patient with multiple sites of metastasis were predominantly gp(C1) positive (92.5%, 37/40 CTCs).
  
  
  CONCLUSIONS
  Together we present here a practical approach to examine rare cell expression of glycan markers. Using this approach, we identified an O-core glyco-determinant gp(C1) as a potential immunological target of bCTCs. Given its bCTC-expression profile, this target warrants an extended investigation in a larger cohort of breast cancer patients.
authors.affiliation: Tumor Glycomics Laboratory, Menlo Park, California, USA; SRI International Biosciences Division, Menlo Park, California, USA. Electronic address: denong.wang@sri.com.
authors.forename: Denong
authors.initials: D
authors.lastname: Wang
authors.affiliation: SRI International Biosciences Division, Menlo Park, California, USA.
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Liu
authors.affiliation: Palo Alto Research Center, Palo Alto, California, USA.
authors.forename: Ben
authors.initials: B
authors.lastname: Hsieh
authors.affiliation: Palo Alto Research Center, Palo Alto, California, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Bruce
authors.affiliation: Departments of Medical Oncology and Therapeutics Research, City of Hope Cancer Center, Duarte, California, USA.
authors.forename: George
authors.initials: G
authors.lastname: Somlo
authors.affiliation: Department of Pathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
authors.forename: Jiaoti
authors.initials: J
authors.lastname: Huang
authors.affiliation: SRI International Biosciences Division, Menlo Park, California, USA.
authors.forename: Lidia
authors.initials: L
authors.lastname: Sambucetti
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D005260:Female; D006031:Glycosylation; D006801:Humans; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000276:immunology*; D010865:Pilot Projects; D011134:Polysaccharides / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D011134:Polysaccharides
keywords: Carbohydrate microarrays; Circulating tumor cells; Metastatic breast cancer; O-glycan cryptic antigens; Tumor immunotyping