Objective This study aimed to determine whether 3q26 gain can predict which low-grade squamous intraepithelial lesions (LSILs) and atypical squamous cells of undetermined significance (ASCUSs) will progress to higher-grade squamous intraepithelial lesion (HSIL).

Methods Liquid cytology specimens of LSIL and ASCUS from 73 women were examined using fluorescent in situ hybridization (FISH) for the detection of 3q26 gain. All women underwent colposcopy and biopsy at the initial visit and 40 of them with histology showing cervical intraepithelial neoplasia 1 (CIN 1) or human papillomavirus infection (koilocytosis) were included in the study. They were reevaluated with liquid cytology, colposcopy, and biopsy after a median follow-up of 17.5 months.

Results A total of 40 cases were analyzed (31 LSILs and 9 ASCUSs). Of these cases, 8 (20%; 6 LSILs and 2 ASCUSs) were positive and 32 (80%) were negative for 3q26 gain according to FISH. Three of the 8 positive women (38%) progressed to HSIL/CIN 2 or worse, whereas none of the 32 negative women did so. 3q26 gain could predict progression with a negative predictive value of 100% (95% confidence interval, 89.1%–100%). In addition, women positive for 3q26 gain had a significantly lower regression rate compared with negative women (P = 0.009).

Conclusions In this first prospective study, 3q26 gain in LSIL/ASCUS cytology exhibited an impressive negative predictive value for progression to HSIL/CIN 2 or worse. Thus, 3q26 gain may be useful in stratifying patients’ risk for progression and possibly alter management and reduce cost of follow-up.