[The diagnostic value of quantitative measurement of a proliferation-inducing ligand mRNA in sputum samples from lung cancer patients].
OBJECTIVE
To establish a real-time fluorescence quantitative polymerase chain reaction (RFQ-PCR) method for quantifying a proliferation-inducing ligand (APRIL) mRNA in sputum samples from patients with non-small cell lung cancer (NSCLC), and to evaluate its role in the diagnosis of NSCLC.


METHODS
Seventy-one cases of NSCLC and 62 cases of benign pulmonary disease were enrolled in this study from August 2007 to May 2008 in Affiliated Hospital of Nantong University, Jiangsu. Sixty-five healthy volunteers served as the control. The fluorescence of the PCR products was detected continuously during the amplification by RFQ-PCR. According to the standard curves created by plasmid DNA, the expression level of target genes in clinical samples was determined using software. The results were presented as the ratios of target genes to beta(2)-microglobulin (beta(2)-M) mRNA, and compared with those obtained by conventional cytological method.


RESULTS
The detection range of the assay was from 38 copies/microl to 3.8 x 10(6) copies/microl. The coefficients of variation values of both intra-experimental and inter-experimental reproducibility were 8.5% and 13.6%, respectively. The expression of APRIL mRNA in tumor sputum was higher than that in benign pulmonary disease and healthy volunteers (t = 10.50, 11.32, P < 0.01). The positive rate for APRIL mRNA expression was 81.7% (58 of 71) in sputum samples of NSCLC, 3.2% (2/62) in benign pulmonary disease and 1.5% (1/65) in healthy volunteers when cut-off values for positivity were set at the x(-) +/- 2 s of mRNA expression in health volunteers. The level of APRIL mRNA of NSCLC was not related to sex, age, smoking status, TNM stage and lymph node metastasis (P > 0.05, respectively), but was related to pathology subtype and the location of tumors (P < 0.05, respectively). The APRIL mRNA assay (82%) produced a higher detection rate than conventional cytological method (14%) (chi(2) = 67.68, P < 0.01).


CONCLUSIONS
Measurement of the expression of APRIL mRNA in sputum by RFQ-PCR showed high sensitivity and specificity, which maybe useful in diagnosing NSCLC.
Sun
Bao-Lan
BL
Department of Laboratory, Affiliated Hospital of Nantong University, Nantong Jiangsu 226001, China.
Zhu
Li
L
Ding
Wei-Feng
WF
Jing
Rong-Rong
RR
Chu
Shao-Peng
SP
Wang
Hui-Min
HM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008024:Ligands; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction / Q000379:methods*; D012333:RNA, Messenger / Q000032:analysis; D012680:Sensitivity and Specificity; D013183:Sputum / Q000737:chemistry*; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13 / Q000032:analysis
D008024:Ligands; D012333:RNA, Messenger; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13