Screening of TERC gene amplification as an additional genetic diagnostic test in detection of cervical preneoplastic lesions.

TERC gene amplification was investigated as a possible diagnostic marker for use in routine cytological screening to improve the accuracy of conventional screening procedures in detection of cervical preneoplastic lesions. Cervical smears were screened and classified as low-grade or high-grade squamous intraepithelial lesions (LSIL or HSIL). A fluorescence in situ hybridization procedure using a TERC-specific DNA probe was performed on the same specimens and TERC gene copy number was evaluated. More than two signals per cell were defined as TERC positive. In cervical smears graded after conization as cervical intraepithelial neoplasia grade 1 (CIN 1), no TERC-positive cases were found in either LSIL or HSIL, and no TERC amplification was found in LSIL cases with histological results CIN 1 and CIN 2. Amplifications of the TERC gene first appeared in HSIL cases with CIN 2 histology. In the CIN 3 group, TERC-positive cases were present in both LSIL and HSIL; in these, there were no statistically significant differences between TERC-positive and TERC-negative cases. Statistically significant differences in TERC-positive cases were found between LSIL and HSIL without regard to the CIN grade. From the results obtained, it can be concluded that TERC gene amplifications inevitably lead to a high risk of CIN 3 in both LSIL and HSIL after cytological smear examination. A high CIN grade is not necessarily correlated with TERC amplification, but a positive TERC result certainly demands a high CIN classification.