Real-time quantitative RT-PCR detection of disseminated endometrial tumor cells in peripheral blood and lymph nodes using the LightCycler System.
OBJECTIVE
Some endometrial cancer patients without clinical evidence of extrauterine spread die as a result of recurrence even after curative operation. These recurrences may arise from occult tumor cells that are not detected by conventional methods. The goal of this study was to develop a quantitative method for the detection of disseminated tumor cells (DTCs) in the peripheral blood (PB) and lymph nodes (LNs) of patients with endometrial cancer.


METHODS
Ninety-eight PB samples from 30 patients and 218 LNs from 14 patients were studied. Real-time quantitative analysis was performed using a LightCycler instrument and a TaqMan probe for cytokeratin 19 (CK19) as a marker gene.


RESULTS
This method resulted in the reproducible quantitation of 10 to 10(6) MCF-7 cells (CK19-expressing breast cancer cell line) per 10(6) peripheral blood nucleated cells. CK19 mRNA expression was detected in 28 PB samples and in 62 LNs. Only three preoperative PB samples and one postoperative PB sample (from four patients) and 33 LNs (from six patients) were PCR-positive. The PCR-positive rate of LNs was higher in patients with pathologically metastatic (path-positive) LNs than in patients with path-negative but PCR-positive LNs. Furthermore, the CK19 mRNA background expression rate was higher in the LNs of path-negative but PCR-positive patients than in LNs of path-negative and PCR-negative patients.


CONCLUSIONS
Real-time qRT-PCR with TaqMan probes is a sensitive, specific and rapid method for the detection of DTCs in PB and LNs. Additional studies with larger numbers of patients and adequate follow-up would be of benefit.
Ji
Xin-Qiang
XQ
Akita University School of Medicine, Division of Obstetrics and Gynecology, Department of Reproductive and Developmental Medicine, 1-1-1 Hondo, Akita-shi, Akita 010-8543, Japan.
Sato
Hirokazu
H
Tanaka
Hidenori
H
Konishi
Yoshitomo
Y
Fujimoto
Toshio
T
Takahashi
Osamu
O
Tanaka
Toshinobu
T
D000368:Aged; D045744:Cell Line, Tumor; D016889:Endometrial Neoplasms / Q000097:blood* / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D007633:Keratins / Q000235:genetics; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*
D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D007633:Keratins