title: Diagnostic and predictive role of cell-free midkine in malignant pleural effusions.
abstract: OBJECTIVE
  The detection of circulating nucleic acids has long been explored for the diagnosis and prognosis of a variety of clinical conditions. The aim of this study was to detect the cell-free mRNA expression of midkine (MK) in patients with effusions and its potential diagnostic and predictive value.
  
  
  METHODS
  Effusions were collected prospectively from 168 patients. The cell-free RNA was extracted from effusions, and the mRNA expression of MK was detected using real-time PCR. The expression of carcinoembryonic antigen (CEA) and biochemical markers in effusions were also assayed. Primary cancer cells were isolated from the malignant effusions (n = 46). Compared with culture cell lines, the response of these cancer cells to chemotherapeutic agents was determined by CCK-8 assay.
  
  
  RESULTS
  The expression of cell-free MK mRNA was significantly higher in the malignant group than in the benign group (0.13 vs 0.01, P < 0.001). The sensitivity and diagnostic accuracy of MK were 77.5 and 81.5 %, while a combination of CEA and MK reached 86.9 % sensitivity and 88.7 % accuracy. In addition, cell-free MK mRNA expression was significantly correlated with inhibitory rate of cisplatin (R = -0.72, P < 0.01).
  
  
  CONCLUSIONS
  Measurement of cell-free MK mRNA levels in effusion supernatant yields a high diagnostic accuracy and a potential predictive value.
authors.affiliation: Immunology and Reproduction Biology Lab, Medical School and State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Lv
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Mou
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Yueqiu
authors.initials: Y
authors.lastname: Chen
authors.forename: Tingting
authors.initials: T
authors.lastname: Wang
authors.forename: Yayi
authors.initials: Y
authors.lastname: Hou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000078792:Midkine; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism; D016066:Pleural Effusion, Malignant / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D011379:Prognosis; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics; D012372:ROC Curve; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; C066254:MDK protein, human; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D000078792:Midkine