Lung cancer metastatic cells detected in blood by reverse transcriptase-polymerase chain reaction and dot-blot analysis.
OBJECTIVE
We analyzed the blood of patients with lung cancer at different stages of presentation for the presence of carcinoembryonic antigen (CEA) mRNA detected by reverse transcriptase-polymerase chain reaction (RT-PCR) combined with the dot-blot procedure as an indicator of micrometastatic malignant cells.


METHODS
We studied 24 lung cancer patients (10 with distant metastases and 14 with no evidence of distant metastases), eight age- and sex-matched patients affected by nonneoplastic respiratory diseases (four smokers), and eight healthy subjects. We used immunohistochemistry and RT-PCR dot-blot analysis to evaluate CEA expression in the neoplastic tissue, and the RT-PCR dot-blot procedure to analyze CEA mRNA in circulating cells.


RESULTS
The RT-PCR dot-blot procedure was highly sensitive aspecific: it detected CEA mRNA in samples of RNA from lung cancer diluted 10(6)-fold with RNA extracted from normal blood cells, and sequence analysis confirmed that the amplified product was CEA. CEA mRNA was found in circulating cells from eight of 10 lung cancer patients with distant metastases (diagnostic sensitivity, 80%) and in four of 14 patients with no evidence of distant metastases. Two of the latter had distant metastases within 6 months of analysis. Thus, the diagnostic specificity of the analysis toward lung cancer without distant metastases was 86%. The analysis was negative in the eight nonneoplastic patients and in the eight healthy controls.


CONCLUSIONS
The RT-PCR dot-blot analysis of CEA mRNA in blood cells seems to be a promising tool for the early detection of micrometastatic circulating cells in patients with lung cancer.
Castaldo
G
G
Dipartimento di Biochimica e Biotecnologie Mediche and Ceinge scarl, Facoltà di Medicina e Chirurgia, Università di Napoli Federico II, Naples, Italy.
Tomaiuolo
R
R
Sanduzzi
A
A
Bocchino
M L
ML
Ponticiello
A
A
Barra
E
E
Vitale
D
D
Bariffi
F
F
Sacchetti
L
L
Salvatore
F
F
D000368:Aged; D000369:Aged, 80 and over; D002272:Carcinoembryonic Antigen / Q000097:blood*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008175:Lung Neoplasms / Q000097:blood; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000175:diagnosis*; D016133:Polymerase Chain Reaction; D012334:RNA, Neoplasm / Q000097:blood
D002272:Carcinoembryonic Antigen; D012334:RNA, Neoplasm