Objective To study the relationship and clinical significance of the serum level of Pro-gastrinreleasing peptide31-98 (ProGRP)and bronchoalveolar lavage fluid for small cell lung cancer of different TNM staging.Methods 96 cases of SCLC with definite pathohistological typing were divided into stage Ⅰ～Ⅱ SCLC group (n=30),stage ⅢSCLC group (n=31),stage IVSCLC group (n=35),and the benign cases (n=90)were taken as control.Using enzyme-linked immunoserbent assay ( ELISA),the serum levels of ProGRP and bronchoalveolar layage fluid of all patients were detected,meanwhile the neuronspecific enolase were served as controls.The relation between serum and bronchoalveolar lavage fluid ProGRP level and small cell lung cancer of different TNM staging was analyzed.Results The serum level of ProGRP in stage Ⅰ～Ⅱ SCLC group,stage Ⅲ SCLC group,stage Ⅳ SCLC group,and the benign group were (295.33±118.56),(421.13±196.66),(758.76±326.19)and (29.68±16.32)μg/mol,respectively (P＜0.01 ).The level in bronchoalveolar lavage fluid ProGRP were ( 516.67 ±208.45),( 1170.55±414.65 ),( 1739.12±696.08 )and (49.23±22.50)μg/mol,respectively (P＜0.01 ).The serum level of NSE in stage Ⅰ～Ⅱ SCLC group,stage Ⅲ SCLC group,stage Ⅳ SCLC group,and the benign group were (10.36±6.76),(24.19±10.88 ),(35.76±17.30)and (9.70 ±5.28)mg/mol.The level in bronchoalveolar lavage fluid NSE were (16.66±11.62),(45.47±20.74),(65.18±29.87)and (9.70±5.28)mg/mol,respectively (P＜0.01).The positive rate of serum ProGRP in stage Ⅰ～Ⅱ SCLC group,stage Ⅲ SCLC group,stage Ⅳ SCLC group,and the benign group were 0.6000,0.7097,0.8286 and 0.0667 ,respectively(P＜0.01).The positive rate in bronchoalveolar lavage fluid ProGRP were 0.6333,0.7419,0.8571 and 0.0444,respectively (P＜0.01).The positive rate of serum NSE in stage Ⅰ～Ⅱ SCLC group,stage Ⅲ SCLC group ,stage Ⅳ SCLC group,and the benign group were 0.2333,0.6774,0.8000 and 0.2222.The positive rate in bronchoalveolar lavage fluid NSE were 0.2667,0.7097,0.8286 and 0.2667 ,respectively(P＜0.01 ).Both the ProGRP level and positive rate in serum and bronchoalveolar lavage fluid were obviously higher in stage Ⅰ～Ⅱ,Ⅲ,and Ⅳ SCLC group than in benign group (P＜0.01 ),both the ProGRP and NSE level and positive rate in bronchoalveolar lavage fluid were obviously higher than that in the serum.The positive rate in serum and bronchoalveolar lavage fluid ProGRP in stage Ⅰ～Ⅱ SCLC group were obviously higher than that in the NSE (P＜0.01),but there was no significant difference in stage Ⅲ and Ⅳ SCLC group.Conclusion ProGRP level in serum and bronchoalveolar lavage fluid have great value to the diagnosis and clinical stages of SCLC,especially the early diagnosis,ProGRP is better than NSE;As to the diagnosis of small cell lung cancer of different TNM staging,ProGRP detection in bronchoalveolar lavage fluid is better than in serum.