Detection of occult metastases in lymph nodes from patients with colorectal carcinoma by reverse transcriptase-polymerase chain reaction.
OBJECTIVE
To detect occult metastases in lymph nodes from patients with colorectal carcinoma and its clinical significance.


METHODS
The metastases in 260 lymph nodes from 39 histologically verified colorectal cancer patients were studied by both hematoxylin-eosin (HE) staining and cytokeratin-20 (CK20) specific RT-PCR. Ten normal lymph nodes were served as negative controls, and HT29 colon cancer cell line and 5 colorectal cancer specimens as positive controls.


RESULTS
Ten normal lymph nodes were CK20-negative, HT29 cells and 5 tumor specimens were all CK20-positive. All 29 lymph nodes from 16 patients which confirmed metastases by HE staining exhibited CK20 positive expression; an additional 28 lymph nodes from 5 patients with no histologically detectable metastases expressed CK20 mRNA, i.e. presence of metastases. The difference of the positivity was significant (11.1% vs 21.9%, P < 0.01). According to the HE staining, the cases of Dukes' A, B, C and D were 3, 20, 12 and 4, respectively. In the 20 patients of Dukes' B stage, 5 of them had CK20-positive lymph nodes.


CONCLUSIONS
CK20-specific RT-PCR is a highly sensitive, specific and simple method for detecting occult metastases in lymph nodes. The detection of CK20 mRNA expression in lymph nodes is recommended to precisely determine tumor stage and postoperative adjuvant therapy for patients with colorectal cancer, and further studies should be done in future to confirm the findings.
Liu
Zhongmin
Z
Department of Surgery, Tai'an Central Hospital and First Teaching Hospitasl of Taishan Medical College, Tai'an, China.
Ye
Xin
X
Bi
Weimin
W
Wang
Mingyu
M
Li
Yi
Y
Chen
Tingwu
T
D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000235:genetics / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D019073:HT29 Cells; D006801:Humans; D007381:Intermediate Filament Proteins / Q000235:genetics; D053554:Keratin-20; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20; D012333:RNA, Messenger