Molecular detection of tumor cells in bronchoalveolar lavage fluid from patients with early stage lung cancer.
BACKGROUND
Conventional cytologic analysis of sputum is an insensitive test for the diagnosis of non-small-cell lung cancer (NSCLC). We have recently demonstrated that polymerase chain reaction (PCR)-based molecular methods are more sensitive than cytologic analysis in diagnosing bladder cancer. In this study, we examined whether molecular assays could identify cancer cells in bronchoalveolar lavage (BAL) fluid.


METHODS
Tumor-specific oncogene mutations, CpG-island methylation status, and microsatellite alterations in the DNA of cells in BAL fluid from 50 consecutive patients with resectable (stages I through IIIa) NSCLC were assessed by use of four PCR-based techniques.


RESULTS
Of 50 tumors, 28 contained a p53 mutation, and the identical mutation was detected with a plaque hybridization assay in the BAL fluid of 39% (11 of 28) of the corresponding patients. Eight of 19 adenocarcinomas contained a K-ras mutation, and the identical mutation was detected with a mutation ligation assay in the BAL fluid of 50% (four of eight) of the corresponding patients. The p16 gene was methylated in 19 of 50 tumors, and methylated p16 alleles were detected in the BAL fluid of 63% (12 of 19) of the corresponding patients. Microsatellite instability in at least one marker was detected with a panel of 15 markers frequently altered in NSCLC in 23 of 50 tumors; the identical alteration was detected in the BAL fluid of 14% (three of 22) of the corresponding patients. When all four techniques were used, mutations or microsatellite instability was detected in the paired BAL fluid of 23 (53%) of the 43 patients with tumors carrying a genetic alteration.


CONCLUSIONS
Although still limited by sensitivity, molecular diagnostic strategies can detect the presence of neoplastic cells in the proximal airway of patients with surgically resectable NSCLC.
Ahrendt
S A
SA
Department of Surgery, Medical College of Wisconsin, Milwaukee, USA.
Chow
J T
JT
Xu
L H
LH
Yang
S C
SC
Eisenberger
C F
CF
Esteller
M
M
Herman
J G
JG
Wu
L
L
Decker
P A
PA
Jen
J
J
Sidransky
D
D
D000483:Alleles; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D018899:CpG Islands; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D017931:DNA Primers; D011905:Genes, ras / Q000235:genetics; D006801:Humans; D017403:In Situ Hybridization; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D008745:Methylation; D018895:Microsatellite Repeats / Q000235:genetics*; D009154:Mutation; D009367:Neoplasm Staging; D009857:Oncogenes / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D019941:Cyclin-Dependent Kinase Inhibitor p16; D017931:DNA Primers; D016159:Tumor Suppressor Protein p53