Cytologic Features of Atypical Cervical Cytology Samples with and without TERC Copy Number Changes
Marc Sanidad, Massih Abawi, JoAnn Kelly, Dan Jones, Yasmine Hijazi. Quest Diagnostics Nichols Institute, Chantilly, VA
Background: Genomic markers, such as chromosome (chr) aneuploidy and/or amplification of the telomerase RNA gene (TERC), are found in the vast majority of high-grade squamous intraepithelial lesions (SIL) but in only a small subset of low-grade SIL lesions. TERC gene profiling shows promise in distinguishing genomically complex atypical lesions from those with just atypical cytologic features. Combining TERC FISH with cytology, we compared morphologic features in cervical samples that had TERC copy number changes with those that lacked them.
Design: TERC FISH analysis was performed on 97 liquid-based cervical samples, prepared by the ThinPrep (n = 43) or the SurePath method (n = 54), with diagnosis by the Bethesda system. Percentages of lesional cells were detemined by a cytopathologist as the proportion of atypical cells compared to total epithelial cells in Pap stains. Genomic status of the TERC loci was evaluated using a FISH probe at chr band 3q26 (hTERC, Kreatech), and normalized with an alpha satellite probe (3q11, Kreatech). Specificity of probe binding was confirmed by analysis of a subset of cases with a different 3q probe (Vysis). 3q26 and 3q11 signals were quantified using fluorescence microscopy by manual count, and with automated microscopy (Metafer 4, MetaSystems) in a subset.
Results: TERC amplification, identified as either chr 3 polysomy or gene-specific amplification, was found in 2/2 of CIS (100%), 25/27 of HSIL (92.6%), 8/26 of ASC-H (30.7%), 2/15 of LSIL (13.3%), and 0/22 negative cases. The two HSILs without TERC amplification showed less than 1% and 2-3% lesional cells, with the former case showing normal cytology on follow-up. All TERC-amplified HSIL cases had at least 3% cytologically lesional cells and the percentage of lesional cells identified by FISH and cytology review were well-correlated (R= 0.53), with cases with the most lesional cells more frequently showing TERC amplification. Among ASC-H lesions, there was a trend towards more cytologically lesional cells in TERC-amplified cases versus those with normal FISH (median 4% vs. 1%). The cases with TERC amplification were more likely to include lesional cells in small sheets and clusters.
Conclusions: TERC copy number changes were found in >90% of HSILs, including all that had at least 3% lesional identified by parallel cytologic counts. Correlates in those ASC-H cases that had TERC amplification included a higher percentage of lesional cells, and their presence in small sheets or clusters. These findings show promise in refining the morphologic features of atypical cytology cases that genetically resemble HSIL.
Monday, March 4, 2013 1:00 PM
Poster Session II # 97, Monday Afternoon