Cytological diagnosis and telomerase activity of cells in effusions of body cavities

Telomerase is a ribonucleoprotein that synthesizes telometric DNA on chromo some ends, and may be related to the aging and immortality of cells. Recent ly, a telometric repeat amplification protocol (TRAP) assay for telomerase activity, using the polymerase chain reaction, was developed. We examined t he limitations of TRAP assay by applying it to a cultured colon cancer cell line (COLO320) and 58 human cytological materials from body cavity effusio ns, and obtained the following results; i) The limits of the TRAP assay wer e 20-50 cells for the COLO320 cell line; ii) One COLO320 cell per 100 norma l blood white cells was detectable; iii) Seventeen of 58 samples were posit ive for telomerase activity in this study. The sensitivity was 69% (9/13) a nd the specificity was 87.5% (28/32) between cytological diagnosis and telo merase activity; iv) Among 29 malignant cases, 15 were positive for telomer ase activity, while there were 11 cytologically positive cases. The positiv e cases detected by the combination of cytology and telomerase activity acc ounted for 21 of the total 29 cases (72.4%). These results suggest that the measurement of telomerase activity in body cavity effusions may be useful as an adjunctive tool for cytological and clinicopathological diagnosis and that this technique is potentially applicable to remnant cytological mater ials.