Clinical Application Of MIC-1in Diagnosis Of Lung Cancer

Objective:To study the clinical value of macrophage inhibitory cytokine-1(MIC-1) as a serum tumor marker for the diagnosis of lung cancer. This experiment will be a preliminary study of MIC-1expression in lung cancer tissues and its relationship with clinical pathological parameters.Methods:The double antibody sandwich ELISA was used to detect serum MIC-1level in324lung cancer patients,48benign pulmonary disease patients and229healthy persons. We detected the serum CEA, CA125, NSE, CYFRA21-land SCC level also. To analyze the performance of serum MIC-1in the diagnosis of lung cancer, the sensitivity of MIC-1was compared with that of CEA, CA125, NSE, SCC and CYFRA21-1. Meanwhile, the relationship between the serum level of MIC-1in lung cancer and its clinical pathological factors were also analyzed. The SP immunohistochemical method was used to determine the expression of MIC-1protein in53cases of NSCLC tissues,10cases of pericarcinoma tissues and4cases lymph node tissues. The relationship between the expression of MIC-1protein in NSCLC and its clinical pathological factors were also analyzed. Using real-time PCR, we detected the expression of MIC-1mRNA in34cases of lung cancer tissues and34cases of matched pericarcinoma tissues. The relationship between the expression of MIC-1mRNA in lung cancer tissues and its clinical pathological factors were analyzed. Meanwhile, its relationship with serum MIC-1level was also analyzed.Result:MIC-1concentration in lung cancer group was significantly higher than that in normal control group (P<0.001) and benign disease group (P<0.001). The specificity and sensitivity were96.5%and71.3%respectively. In different subtypes of lung cancer, the sensitivity of serum MIC-1was highest in sarcomatoid carcinoma group. The serum level of MIC-1was higher in differentiated groups+low differentiation group than high differentiation group (P=0.022). The sensitivity of MIC-1for early stage lung cancer was higher than CEA, CA125, NSE, SCC and CYFRA21-1respectively.The sensitivity of MIC-1for early stage lung cancer (stage I and stage II) was higher than the combination of the above five markers. The sensitivity of MIC-1for stage I and stage II was improved to77.1%and83.3%respectively in the combination of the six markers. There was no clear evidence of relationship between serum MIC-1level and tumor pathological types and TNM staging (P>0.05). After treatment, disease progression and recurrence of MIC-1serum levels were significantly higher than before treatment. In53cases of NSCLC tissues, the positive rate of MIC-1expression was52.8%. There was no expression of MIC-1protein in10cases of pericarcinoma tissues and4cases lymph node tissues, and there was no metastasis of NSCLC in4cases lymph node tissues(P<0.05). In different subtypes of lung cancer, the positive rate of MIC-1expression was highest in sarcomatoid carcinoma group (100.0%), followed by adenocarcinoma (60.0%) and squamous cell carcinoma (31.3%)(P=0.045). There was no statistically significant difference between34cases lung cancer tissues and the matched pericarcinoma tissues. There was a positive linear correlation between the expression of MIC-1mRNA in lung cancer tissues and its serum MIC-1level.Conclusions:The present study confirms the excellent clinical value of MIC-1in the diagnosis of lung cancer in a large sample scale. There is a certain correlation between the serum MIC-1level and the expression of MIC-1mRNA in lung cancer, which could be related to the development of cancer cells. Serum MIC-1level may be an ideal marker in screening and diagnosis of lung cancer.