The tumor associated CA-125antigen for diagnosis and follow-up of ovarian cancer was well defined. Increased serum CA125 level may have many diagnoses other than ovarian cancer, including breast, colorectal and lung cancer. 80% lung cancer patients were diagnosed at advanced stage. Malignant pleural effusion secondary to lung cancer represented the condition of cancer cell involved pleura.

The CA-125 level may reflect the extent of tumor involved in pleura (tumor burden), it could be correlated with the prognosis. This study was performed to examine the properties of CA-125 by measuring pleural and blood CA-125 levels in lung cancer with or without malignant pleural effusion; meanwhile to examine whether the rate of decline in CA 125 during primary therapy as a surrogate indicator for survival.

Inclusion Criteria:

• Histologically proved lung cancer

Exclusion Criteria:

• History of other cancers within the past 5 years
• Pregnancy or breast milk feeding
• TB pleuritis and peritonitis

Patient with histologically proved lung cancer