Quantification of colorectal cancer micrometastases in lymph nodes by nested and real-time reverse transcriptase-PCR analysis for carcinoembryonic antigen.

Abstract

PURPOSE:

Reverse-transcriptase PCR (RT-PCR) assays for carcinoembryonic antigen (CEA) have been described to identify lymph node micrometastases. These assays are not quantitative and can be confounded by false-positive results. The purpose of this study was to determine whether quantification of CEA in lymph nodes could more readily identify clinically relevant groups.

EXPERIMENTAL DESIGN:

Specimens included 400 lymph nodes from 64 patients undergoing colon resections. Specimens were tested by immunohistochemistry and by RT-PCR using nested primers for CEA. Specimens from 59 patients that were positive by nested RT-PCR were further quantified by detection of CEA mRNA fluorescence increase at a threshold PCR cycle.

RESULTS:

CEA was detected by nested RT-PCR analysis in 4 of 34 (12%) nodes of nonneoplastic disease, 2 of 13 (15%) nodes from T(1)N(0) patients, 32 of 81 (40%) nodes of T(2)N(0) patients, 49 of 109 (45%) nodes from T(3)N0 patients, and 92 of 163 (56%) nodes from T(1-4)N(1-2) patients. The overall presence of any RT-PCR-detectable CEA in nodes did not differentiate patient groups. Immunohistochemistry was positive in nodes from 7% of T(3)N(0) patients and 100% of T(1-3)N(1-2) patients. CEA quantification revealed that 0 of 7 patients with nonneoplastic disease and 2 of 17 (12%) patients with stage I T(1-2)N(0) cancers had one or more lymph nodes with >/=1.0 x 10(2) CEA transcripts per sample. In contrast, 4 of 13 (31%) patients with stage II T(3)N(0) cancer and 10 of 22 (45%) stage III patients with known metastases had lymph nodes with >/=1.0 x 10(2) CEA transcripts.

CONCLUSIONS:

These data suggest that quantification of CEA levels in lymph nodes may more accurately identify patients at risk for cancer recurrence than does routine nested RT-PCR or immunohistochemistry.

• Authors: Samuel B Ho, Ann Hyslop, Richard Albrecht, Amanda Jacobson, Michael Spencer, David A Rothenberger, Gloria A Niehans, John D'Cunha, Robert A Kratzke
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 10 Issue 17 Pg. 5777-84 (Sep 01 2004) ISSN: 1078-0432 [Print] United States
• PMID: 15355906 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Carcinoembryonic Antigen
• RNA, Messenger
• RNA, Neoplasm

Topics

• Carcinoembryonic Antigen (genetics, metabolism)
• Colorectal Neoplasms (genetics, metabolism, secondary)
• Humans
• Immunoenzyme Techniques
• Lymph Nodes (pathology)
• Lymphatic Metastasis
• Neoplasm Staging
• Polymerase Chain Reaction
• Prospective Studies
• RNA, Messenger (metabolism)
• RNA, Neoplasm (genetics)
• Reverse Transcriptase Polymerase Chain Reaction
• Sensitivity and Specificity