title: Quantification of rare circulating tumor cells in non-small cell lung cancer by ligand-targeted PCR.
abstract: BACKGROUND
  Quantification of circulating tumor cells (CTC) is valuable for evaluation of non-small cell lung cancer (NSCLC). The sensitivity of current methods constrains their use to detect rare CTCs in early stage. Here we evaluate a novel method, ligand-targeted polymerase chain reaction (LT-PCR), that can detect rare CTCs in NSCLC patients.
  
  
  METHODS
  CTCs were enriched by immunomagnetic depletion of leukocytes and then labeled by a conjugate of a tumor-specific ligand and an oligonucleotide. After washing off free conjugates, the bound conjugates were stripped from CTCs and then analyzed by qPCR. To evaluate the clinical utility, blood samples were obtained from 72 NSCLC patients (33 initially diagnosed and 39 on chemotherapy), 20 benign patients, and 24 healthy donors.
  
  
  RESULTS
  Experiments with healthy blood spiked with tumor cells indicated the LT-PCR allows specific detection of CTC. The clinical study showed that the initially diagnosed patients have an average of 20.8 CTC units with metastatic diseases, 11.8 CTC units with localized diseases, and 6.0 CTC units with benign diseases. With the threshold of 8.5 CTC units, the assay can detect 80% of stage I/II, 67% of stage III, and 93% of stage IV cancer. With the benign patients and healthy donors as control group, the method can detect cancer with a sensitivity of 81.8% and a specificity of 93.2%.
  
  
  CONCLUSIONS
  The LT-PCR would allow quantification of CTC in NSCLC patients at a more sensitive level, providing a potential tool for stratifying malignant lung diseases, especially at early stage.
authors: Department of Clinical Laboratory, Shanghai Chest Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China.
authors: Jiatao
authors: J
authors: Lou
authors: Suqin
authors: S
authors: Ben
authors: Guohua
authors: G
authors: Yang
authors: Xiaohui
authors: X
authors: Liang
authors: Xiaoqian
authors: X
authors: Wang
authors: Songshi
authors: S
authors: Ni
authors: Baohui
authors: B
authors: Han
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D016022:Case-Control Studies; D002452:Cell Count / Q000295:instrumentation / Q000379:methods*; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D018189:Immunomagnetic Separation; D047589:Leukocyte Reduction Procedures; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D015345:Oligonucleotide Probes / Q000737:chemistry; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D015345:Oligonucleotide Probes