Abstract

Background/Aims
Telomerase and telomerase reverse transcriptase (hTERT), are specifically expressed in cancer cells, making them candidate markers for the early detection of cancer. The aims of our study were to determine whether these assays may be useful in the diagnosis of colorectal cancer (CRC) developed in ulcerative colitis (UC) patients. Methods: Luminal washings and biopsies were collected during colonoscopy in 66 patients; 34 with CRC, 21 with UC, and 11 controls. Telomerase activity was detected by telomeric repeat amplification protocol (TRAP) and hTERT was assayed by RT-PCR. Results: Telomerase activity was detected in biopsies from 33/34 (97%) CRC, 14/21 (67%) UC, and 3/11 (27%) controls. hTERT was positive in biopsies from 32/34 (94%) CRC, 12/21 (57%) UC, and 5/11 (45%) controls. In washing fluid, 21/34 (62%) of CRC patients were positive for telomerase, but UC patients and controls were negative. The sensitivity of telomerase for CRC was 97% in tissues and 62% in washing fluid. The specificity of telomerase in washing fluid was 100%, whereas the specificity of telomerase or hTERT mRNA in tissues was 47% each. Conclusions: The low specificity of telomerase and hTERT in colonic tissue suggest that these are not candidate markers for CRC arising in UC. Telomerase in colonoscopic luminal washings, however, may be a novel marker for early CRC in UC. (Intestinal Research 2004;2:15-20)

• Keywords: Colorectal cancer, Ulcerative colitis, Telomerase, hTERT, Colonoscopy