title: Expression of Yes-associated protein in non-small cell lung cancer and its relationship with clinical pathological factors.
abstract: BACKGROUND
  Yes-associated protein (YAP) plays an important role in signal transduction and gene transcription regulation in normal cells, with elevated and over-expressed YAP levels observed in various malignant tumors. The aim of this study was to investigate the expression of YAP in non-small cell lung cancer (NSCLC), and to study the possible relationship of YAP expression with the occurrence and development of NSCLC.
  
  
  METHODS
  YAP expression was assessed in 40 cases of NSCLC tumor tissues by immunohistochemistry, and their protein and mRNA levels were evaluated through Western blotting and reverse transcription-polymerase chain reaction (PCR), respectively. Normal lung tissues obtained from the same patient were used as control. Statistical analysis was performed to correlate the YAP expression to clinical pathological factors, such as tumor type, stage and grade.
  
  
  RESULTS
  YAP-positive expression was found in 28 (70%) of the 40 cases of NSCLC, which included 10 cases of squamous cell carcinoma (25%), 17 cases of adenocarcinoma (42.5%) and 1 case of squamous adenocarcinoma (2.5%). In the 28 YAP-positive cases, 19 cases showed lymph node metastasis and were classified in TNM stage II + III (47.5%); the other nine cases showed no lymph node metastasis (22.5%) and were classified in the TNM stage I. There was no relationship between YAP expression and patients' age, gender or tumor histological grades. However, YAP showed significant over expression in late period of T stage (P = 0.012), TNM stage (P = 0.039), and lymph node metastasis (P = 0.013), respectively. Notably, YAP-positive expression was significantly higher in adenocarcinoma than that in squamous cell carcinoma (P = 0.041).
  
  
  CONCLUSIONS
  Over-expression of YAP was associated with NSCLC, especially lung adenocarcinoma. The high YAP expression in late period of tumor stage and lymph node metastasis may indicate that YAP expression could be an early marker for NSCLC tumorigenesis.
authors.affiliation: Department of Respiratory Medicine, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China.
authors.forename: Li-li
authors.initials: LL
authors.lastname: Su
authors.forename: Wei-xia
authors.initials: WX
authors.lastname: Ma
authors.forename: Jian-feng
authors.initials: JF
authors.lastname: Yuan
authors.forename: Yang
authors.initials: Y
authors.lastname: Shao
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.forename: Shu-juan
authors.initials: SJ
authors.lastname: Jiang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000368:Aged; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D010750:Phosphoproteins; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human