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M.D. Lozano Escario
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P1.02 - Poster Session with Presenters Present (ID 454)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Biology/Pathology
- Presentations: 2
- Moderators:
- Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)
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P1.02-027 - A Comparative Analysis of Different Cytological Samples for the Assessment of ALK Gene Rearrangements in NSCLC Patients (ID 5160)
14:30 - 14:30 | Author(s): M.D. Lozano Escario
- Abstract
Background:
Determination of ALK gene rearrangements has been traditionally performed in biopsies and/or surgical specimens. However, advanced lung cancer is often diagnosed by FNA cytology obtained through minimally invasive procedures, and frequently cytological specimens are the only samples available, thus emphasizing the necessity to expand ALK analysis to cytologic specimens. We assessed the feasibility of determining ALK gene rearrangements in different types of cytological samples.
Methods:
We studied prospectively 268 cytological samples from 268 NSCLC patients for ALK gene rearrangements by FISH (Vysis LSI ALK Dual Color Break Apart and ZytoLight SPEC ALK Dual Color Break Apart). Tumour samples were obtained by bronchoscopy -FNA in 45 cases (19.79%), EBUS-FNA in 63 (23.50%), EUS-FNA in 56 (20.89%), CT-FNA in 28 (10.44%), Ultrasonography guided-FNA in 24 (8.95%), and direct FNA in 23 cases (8.58%). Two cavity fluids (0.74%), 4 imprints from surgical specimens (1.49%), and 22 cases received for consultation (8.20%) were also studied. ROSE was done in all FNA procedures. FISH was performed on stained smears in 133 cases (49.62%) (114 Papanicolau and 19 Diff-Quick), ThinPrep in 48 (17.91%), SurePath in 12 (4.47%), and cell block in 75 cases (27.98%). All cases were tested for EGFR and KRAS mutations.
Results:
Two hundred thirty five samples (87.68%) were adequate for FISH analysis. Fifteen cases (5.59%) had ALK gene rearrangements. One case had a concurrent EGFR mutation in exon 21 plus the T789M mutation, and two had also KRAS mutations (G12D and G12C respectively). FISH study was unsuccessful in 33 cases (12.31%): 8 from stained smears (6.01%), 12 from ThinPrep (25%), 8 from SurePath (66.66%), and 5 from cell blocks (6.66%). Correlation cytological / paraffin embedded samples was performed in 10 cases with a concordance rate of 100%.
Conclusion:
ALK gene rearrangements may be definitely detected in cytological samples and particularly in direct smears. Both, Papanicolau and Diff-Quick smears are suitable samples for FISH analysis. The nuclei on cytology smears are not truncated, which allows for the detection of the true number of FISH signals in a nucleus. It is mandatory an exquisite management and care of the samples to preserve quality. Coexistence of ALK gene rearrangements and EGFR and KRAS mutations were observed in one and two cases respectively, indicating that such alterations are not necessarily mutually exclusive
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P1.02-053 - Comparison of Two Different Commercially Available Probes for the Detection of ALK Rearrangements in Cytological Smears (ID 6083)
14:30 - 14:30 | Author(s): M.D. Lozano Escario
- Abstract
Background:
Many patients with NSCLC are diagnosed at advanced stages. A high percentage of those patients have only cytological samples for morphological and molecular analysis. Furthermore ALK analysis by FISH has to be performed using a specific commercially available probe. The aim of this study is to compare two different commercially available probes for analysis of ALK gene rearrangements by FISH using cytological stained smears.
Methods:
We analyzed 37 cytological stained smears from 37 consecutive cases of FNA (14 Diff-Quick and 23 Papanicolau). ROSE was performed in all procedures. The status of EGFR, KRAS and BRAF was kwon in 28 patients. Two probes were used: LSI ALK BREAK APART (Vysis, Ref: 53206N38020, Izasa) was apply in all 37 cases. Additionally, in 25 of these cases we used the ZytoLight SPEC ALK Dual Color Break Apart (ZYTOVISION, Ref: Z-2124-200, Menarini Diagnostics) probe. Protocols were modified from Basel and Zytolight manufacture guidelines. In order to optimize the amount of probe and to evaluate individual nuclei, we delimited an area on each smear with no nuclear overlap.
Results:
All cases were adenocarcinomas. Two cases showed ALK rearrangement (5.4%). Of the 34 negative cases, 27 were negative-polysomic (77.14%). One case was no assessable (2.7%) due to the impossibility of getting hybridization. Concordance between two probes was 100%. No differences were found between Papanicolau and DiffQuick stained smears .
Conclusion:
FISH-ALK in cytological stained smears gives excellent results. Both commercially avialable probes showed identical performance, both are equally valid. No differences between Papanicolau and Diff-Quick stained smears were observed. In our experience, stained cytological smears are the best choice for the analysis of ALK rearrangements in NSCLC patients, keeping paraffin for cases in which adequate cytological smears are not available.
