Detection of micrometastatic cancer cells in bone marrow from patients with gastric cancer

초록

Objectives: At present, the imaging and biochemical tests of clinical field are unsatisfactory to detect minimal residual tumor and occult metastasis in gastric cancer. there are not sufficient reports to demonstrate clinical roles of CEA or cytokeratin mRNA in other gastrointestinal cancer including gastric cancer. The aim of present study was to determine whether micrometastatic cancer cells can be detected in bone marrow by using CEA and cytokeratin 20 (CK20) and whether micrometastasis is related to prognostic factors. Methods: The study population was consist of 52 patients with gastric cancer who underwent surgical therapy in Inha university hospital, South Korea from November 2000 to August 2001. Bone marrow aspirate 1.5mL was obtained from selected patients and then RNA was extracted from these samples using centrifugation. cDNA was synthesized from the extracted RNA by using reverse transcription and amplified by performing nested PCR using GAPDH, CEA and CK20 primers. Then, agarose gel electrophoresis was performed to the amplified PCR products. Human colon cancer cell line, HT-29, was used as the positive control of this method, whereas bone marrow aspirate of patients with non-carcinomatous diseases was used as the negative control. Results: Among 52 patients, CEA, CK20 mRNA and both was detected from 18 patients (34.6%), 11 patients (21.2%) and 2 patients (3.8%), respectively. Among 6 negative controls, CEA mRNA was detected from 1 patient (16.7%), and CK20 mRNA was not detected from all patients. There is no correlation of CEA and CK20 mRNA expression with AJCC staging, tumor extent, node metastasis, differentiation, Lauren classification and gross classification of Borrmann. Conclusions: In the present study, the positive rate of CEA and CK20 mRNA in bone marrow using RT-PCR was consistent with the previous reports, whereas correlation of these markers expression with prognostic factors of gastric cancer was not documented.