Detection of Epithelial Cells by RT-PCR Targeting CEA, CK20, and TEM-8 in Colorectal Carcinoma Patients Using OncoQuick Density Gradient Centrifugation System

Background

The detection of epithelial-specific mRNA correlates well with the presence of cancer cells in the peripheral blood and provides a rational explanation for subsequent metastasis.

Material and methods

Forty-two, patients with colorectal cancer and 14 controls were included in our study. Peripheral blood samples were acquired at 24 h before and 48 h after laparotomy. Tissue samples were also acquired from the primary lesion. All samples were examined for the expression profile of CEA, CK20, and TEM-8.

Results

Tissue samples expressed CEA in every specimen, CK20 in 30, and TEM-8 in 41. CEA and CK20 were not identified in the control blood samples while TEM-8 was detected in 4. CEA was detected in 17, CK20 in 28 and TEM-8 in 23, of the preoperative blood samples. CEA mRNA expression in preoperative blood sample and TNM stage were found independently associated with increased tumor size. Positive CEA, CK20, and TEM-8 signals were found in 25, 25, and 23 of the postoperative blood samples respectively.

Conclusions

CK20 and CEA are significantly more frequently detected in colon cancer patients than in healthy controls and can serve as markers. Cancer cell mRNA is commonly detected in the preoperative and postoperative peripheral blood samples. Tumor size was independently associated with the preoperative detection of CEA mRNA. Although TEM-8 mRNA detection in the peripheral blood showed no specificity for cancer patients or correlation with clinical stage, identification and validation of genes and proteins implicated in metastatic process needs to be further investigated.

Key Words: circulating mRNA, CEA, CK20, TEM-8, colon cancer