Expression of targeting protein for xklp2 associated with both malignant transformation of respiratory epithelium and progression of squamous cell lung cancer.
OBJECTIVE
Expression of targeting protein for Xklp2 (TPX2), a microtubule-associated protein, is tightly cell cycle regulated. Abnormally expressed TPX2 has been reported in various malignancies, but less is known in lung cancer. The present study appraised the significance of TPX2 aberrant expression for tumorigenesis and progression of human squamous cell carcinoma (SCC) in lung.


RESULTS
The expressive status of TPX2 was firstly examined with lung cancer (L, PAa, and PG) and immortalized bronchial epithelial (C45, M-BE, Tr, and Y-BE) cell lines, and TPX2 expression was detected at both RNA and protein levels by reverse transcription-PCR and Western blotting, respectively. Immunofluorescence staining on M-BE cells showed that the subcellular localization of TPX2 protein is in nucleus at interphase and mitotic spindle at metaphase. Immunohistochemical analyses were subsequently done on the precancerous lesions derived from 114 patients and the tumor tissues of 432 patients with SCC in lung. Extremely low levels of TPX2 protein were found in the normal bronchial epithelia and alveoli, whereas gradually increased TPX2 protein levels were observed in the squamous metaplasia, dysplasia, carcinoma in situ, and invasive tumor tissues. Statistical analysis showed that the TPX2 immunohistochemistry labeling index was correlated with the differentiation grade, stage, and lymphous metastasis of SCC in lung and that TPX2 overexpression is significantly associated with decreased 5-year survival rate of the patients.


CONCLUSIONS
Aberrant expression of TPX2 may play important role(s) in both malignant transformation of respiratory epithelium and progression of squamous cell lung cancer and could serve as a prognostic predictor for the disease.
Department of Etiology, Cancer Institute, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
Ying
Y
Ma
Dongmei
D
Lin
Wenyue
W
Sun
Ting
T
Xiao
Jinsong
J
Yuan
Naijun
N
Han
Suping
S
Guo
Xiaoli
X
Feng
Kai
K
Su
Yousheng
Y
Mao
Shujun
S
Cheng
Yanning
Y
Gao
D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D018450:Disease Progression; D004848:Epithelium / Q000378:metabolism / Q000473:pathology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000235:genetics*; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics*; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics; D010750:Phosphoproteins / Q000032:analysis / Q000235:genetics; D011379:Prognosis; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis
D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012334:RNA, Neoplasm; C122167:TPX2 protein, human