Detection and quantification of circulating tumor cells in patients with esophageal cancer by real-time polymerase chain reaction.
Polymerase chain reaction (PCR) amplification was used for detecting circulating tumor cells. However, PCR was so sensitive that it detected a very low level of mRNA with no relevance to tumor cells. We analyzed the degree of micro-tumor spread in esophageal cancer patients using quantitative PCR. Samples were collected from 28 patients and 35 controls. Real-time quantitative PCR (LightCycler) was employed for the detection of carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20). In the CEA and CK-20 mRNA assays, 7 and 3 out of 28 patients, respectively, showed higher mRNA levels in peripheral blood than the normal range based on values of controls (mean+/-2SD). Eleven out of 19, 4 out of 14, and 2 out of 5 patients showed higher CEA mRNA levels in the samples from tumor drainage vein, costal bone marrow, and thoracic duct lymph, respectively. One of the 7 patients who showed higher CEA mRNA levels in pretreatment peripheral blood is currently free from disease. These findings reveal that quantitative PCR can discriminate high levels of cancer-specific expression from low levels of illegitimate expression in blood. They also suggest that the identification of circulating tumor cells by the CEA mRNA assay is a reliable means of predicting early recurrence.
Ito
H
H
Niigata University Graduate School of Medical and Dental Sciences, Niigata City, Japan.
Kanda
T
T
Nishimaki
T
T
Sato
H
H
Nakagawa
S
S
Hatakeyama
K
K
D000368:Aged; D000369:Aged, 80 and over; D002272:Carcinoembryonic Antigen / Q000097:blood; D002294:Carcinoma, Squamous Cell / Q000097:blood* / Q000175:diagnosis; D018076:DNA, Complementary / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000097:blood* / Q000175:diagnosis; D005260:Female; D006801:Humans; D007381:Intermediate Filament Proteins / Q000097:blood; D053554:Keratin-20; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D012008:Recurrence; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
D002272:Carcinoembryonic Antigen; D018076:DNA, Complementary; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20; D012333:RNA, Messenger