2984

GUCY2C

guanylate cyclase 2C;GUCY2C;guanylate cyclase 2C

GC-C|STA receptor|guanylyl cyclase C|hSTAR|heat stable enterotoxin receptor|heat-stable enterotoxin receptor|intestinal guanylate cyclase

12p12

protein-coding

PURPOSE: To determine the role of gelatinase in the hepatic metastatic process of colorectal cancer, we correlated gelatinolytic activity in colorectal tumor tissue both to the presence of intravasated colorectal epithelial cells and to the formation of liver metastasis. EXPERIMENTAL DESIGN: The gelatinolytic activity was analyzed in tumor tissue samples from 68 colorectal cancer patients by using gelatin substrate zymography. The presence of intravasated colorectal epithelial cells was defined as detection of guanylyl cyclase C mRNA in blood sampled from drainage vein of a tumor-bearing colorectal segment. RESULTS: Forty of 68 patients were noted to have guanylyl cyclase C mRNA expression in their drainage venous blood. Fifteen patients were noted to have liver metastasis at the time of surgery, and another 15 patients developed liver metastasis during median follow-up period of 53 months. Either individual or total gelatinolytic activity in colorectal tumor tissue failed to predict the presence of intravasated colorectal epithelial cells in the drainage venous blood or formation of liver metastasis. Presence of both intravasated colorectal epithelial cells and high total gelatinolytic activity in colorectal tumor tissue, however, is a strong predictor of liver metastasis (P = 0.004). CONCLUSION: Our data suggested that gelatinolytic activity in colorectal tumor tissues may facilitate the hepatic metastatic process in the steps after intravasation but not during or before intravasation.

Guanylyl cyclase C (GCC) is expressed exclusively in normal intestinal mucosal cells, primary and metastatic colorectal cancers (CRC). The aim of this study was to determine the possible association between the GCC expressions in peripheral blood, prognostic parameters and response to chemotherapy in CRC patients. Fourty-nine metastatic CRC patients and 41 healthy controls with similar age and sex were included to this study. Peripheral blood GCC expressions are measured by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. Interstingly, no GCC expression was measured in healthy controls but GCC expressions of the patients were detectable. Although there was a significant reduction in GCC expressions in 30 patients with regression (from 5.46 +/- 4.12 to 0.06 +/- 0.03, p < 0.0001), marked increase in GCC expressions was observed in 19 patients with progression following chemotherapy (from 0.43 +/- 0.19 to 1.38 +/- 0.52, p = 0.0174). Significant correlation was found between the GCC expressions and carbohydrate antigen 19-9 (CA19-9) levels (p = 0.0041) in 30 patients with regression before chemotherapy. Marked correlation was also detected between the GCC expressions and carcinoembryonic antigen (CEA) levels (p = 0.0072) in 19 patients with progression before chemotherapy. The results of the present study suggest that peripheral blood GCC expressions along with CEA and CA19-9 can be used to determine the early respose to chemotherapy in patients with metastatic CRC. These findings imply that higher expression of GCC in peripheral blood seems to be an indicator of good therapeutic response to chemotherapy and remission. Monitoring the peripheral blood GCC expressions may allow employing different treatment options to metastatic CRC patients.