Abstracts
1999 Digestive Disease Week

# 2081 PROGNOSTIC SIGNIFICANCE OF GUANYLYL CYCLASE C (GCC) MRNA IN LYMPH NODES FROM PATIENTS WITH STAGE II COLORECTAL CANCER
B Cagir, A Gelman, E Bittner, E Weaver, J Palazzo, D Weinberg, R Fry, S Waldman, Jefferson Med Coll, Philadelphia, PA/center>

Introduction: GCC is expressed only by intestinal enterocytes and colorectal cancer cells. This study examined the correlation between GCC mRNA in mesenteric lymph nodes and colorectal cancer recurrence.
Methods: Thirty patients with TNM stage II colorectal cancer who underwent curative resection were selected. Group I included 17 patients with no disease recurrence >8 years and Group II included 11 patients who developed recurrences within 8 years of resection. Sections from resected paraffin-embedded lymph nodes were pooled, total RNA isolated, and reverse transcription followed by the polymerase chain reaction (RT-PCR) performed.
Results: Five patients in Group I and 3 in Group II demonstrated insufficient mRNA; these patients were excluded from analysis. RT-PCR with GCC-specific primers of RNA from Group II patients yielded a product consistent with amplification of GCC mRNA. All Group II patients with a history of cancer recurrence were positive for GCC. In contrast, none of the Group I patients were positive.
Conclusions:This study suggests a correlation between recurrence of colorectal cancer and detection of GCC expression in lymph nodes. These data support the hypothesis that recurrence in patients with Stage II disease reflect micrometastases in lymph nodes that are undetected by histopathology. Also, they suggest that RT-PCR analysis of GCC may be useful in more accurate disease staging. Supported by NIH RO1 R01 CA75123 and Targeted Diagnostics and Therapeutics, Inc. A.G. was supported by NIH 5T32 GM08562.

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