[Clinical significance of detection of cathepsin X and cystatin C in the sera of patients with lung cancer].
OBJECTIVE
Cathepsin X (Cat X) has been identified as a member of cathepsin family. Studies have shown that Cat X is involved in tumorigenesis and tumor development of various cancers. The aim of this study is to investigate the relationship between the clinicopathological prognosis and the levels of Cat X and cystatin C in the serum of patients with lung cancer.


METHODS
Blood samples were collected from 84 patients with lung cancer and 36 healthy control subjects. Cat X and cystatin C were determined by quantitative ELISA.


RESULTS
Cat X and cystatin C levels were significantly higher in the patients with lung cancer than that in the healthy control subjects (P<0.01). Cat X level was correlated with the pathological types of lung cancer (P=0.076). Cystatin C was positively correlated with TNM stage (P=0.01). Furthermore, cystatin C/Cat X was correlated with lymph node metastasis (P=0.058). The patients with high Cat X levels experienced significantly shorter overall survival rates compared with those with low Cat X. Univariate analysis indicated that Cat X and TNM stage were related to overall survival. Multivariate Cox analysis indicated that TNM stage may be used as an independent prognostic variable in patients with lung cancer.


CONCLUSIONS
Cat X and cystatin C levels were significantly higher in patients with lung cancer. Cat X and cystatin C detection in the sera may contribute to the diagnosis of lung cancer and may be used to evaluate the prognosis of patients with NSCLC.
Department of Respiratory Medicine, the Second Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an 710004, China.
Xuede
X
Zhang
Yanli
Y
Hou
Zequn
Z
Niu
Wei
W
Li
Xia
X
Meng
Na
N
Zhang
Shuanying
S
Yang
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002403:Cathepsins / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models
D055316:Cystatin C; D002403:Cathepsins