Validation of ALK/ROS1 Dual Break Apart FISH Probe probe in non-small-cell lung cancer
Sun Min Lim1, Hyun Chang2, Yoon Jin Cha3
1Division of Medical Oncology, Department of Internal Medicine, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea; Division of Medical Oncology, Department of Internal Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, Republic of Korea.
Background:
ALK and ROS1 gene rearrangements are distinct molecular subsets of non-small-cell lung cancer (NSCLC), and they are strong predictive biomarkers of response to ALK/ROS1 inhibitors, such as crizotinib. Thus, it is clinically important to develop an effective screening strategy to detect patients who will benefit from such treatment. In this study, we aimed to validate analytical performance of Vysis ALK/ROS1 Dual Break Apart Probe Kit (RUO) in NSCLC.
Methods:
Study population composed of three patient cohorts with histologically confirmed lung adenocarcinoma (patients with ALK rearrangement, patients with ROS1 rearrangement and patients with wild-type ALK and ROS1). Specimens consisted of 12 ALK-positive, 8 ROS1-positive and 21 ALK/ROS1-wild type formalin-fixed paraffin-embedded samples obtained from surgical resection or excisional biopsy. ALK rearrangement was previously assessed by Vysis ALK Break Apart FISH Probe Kit (Abbott Molecular, Abbot Park, IL, USA) and ROS1 rearrangement was previously assessed by ZytoLight® SPEC ROS1 Break Apart Probe (ZytoVision, GmbH). All specimens were re-evaluated by Vysis ALK/ROS1 Dual Break Apart Probe Kit. FISH images were scanned on BioView AllegroPlus system and interpreted via BioView SoloWeb remotely.
Results:
For a total of 41 patient samples, the concordance of the results by Vysis ALK/ROS1 Dual Break Apart Probe Kit was evaluated and compared to the known ALK and ROS1 rearrangement status of the specimen. Of the 12 ALK-positive cases, hybridization with Vysis ALK/ROS1 Dual Break Apart Probe Kit was successful in 10 cases (success rate 10/12, 83%) and of these 10 cases, all showed ALK rearrangement (100% concordance with the results of Vysis ALK Break Apart FISH Probe Kit). Two of the ALK+ cases were excluded due to weak ROS1 signals that could not be enumerated. Of the 8 ROS1-positive cases, 6 cases were successfully evaluated using Vysis ALK/ROS1 Dual Break Apart Probe Kit. The success rate was 75% (6/8), and of these 6 cases, all showed ROS1 rearrangement, giving a 100% concordance with ZytoLight® SPEC ROS1 Break Apart Probe. Two of the cases were excluded due to weak ROS1 gold signal or high background. In the cohort of 21 wild-type cases, the success rate using Vysis ALK/ROS1 Dual Break Apart FISH Probe Kit was 85% (18/21) and the concordance with ALK and ROS1 probe kit was 100% (18/18).
Conclusion:
Vysis ALK/ROS1 Dual Break Apart Probe Kit (RUO) can detect ALK and ROS1 rearrangement simultaneously in NSCLC.
Insights
The Vysis ALK/ROS1 Dual Break Apart Probe Kit effectively detects ALK and ROS1 gene rearrangements in non-small-cell lung cancer (NSCLC). This validated kit aids in identifying patients who can benefit from targeted ALK/ROS1 inhibitor therapies.
Area of Science:
- Oncology
- Molecular Diagnostics
- Genetics
Background:
- Anaplastic lymphoma kinase (ALK) and ROS1 gene rearrangements define distinct molecular subsets of non-small-cell lung cancer (NSCLC).
- These rearrangements are critical predictive biomarkers for response to ALK/ROS1 inhibitors, such as crizotinib.
- Effective screening strategies are essential for identifying NSCLC patients who will benefit from targeted therapies.
Purpose of the Study:
- To validate the analytical performance of the Vysis ALK/ROS1 Dual Break Apart Probe Kit (RUO) for detecting ALK and ROS1 rearrangements in NSCLC.
- To assess the concordance of the Vysis ALK/ROS1 Dual Break Apart Probe Kit with existing FISH probe kits for ALK and ROS1.
- To evaluate the simultaneous detection capability of the Vysis ALK/ROS1 Dual Break Apart Probe Kit.
Main Methods:
- Study population included 41 patients with histologically confirmed lung adenocarcinoma: 12 ALK-positive, 8 ROS1-positive, and 21 ALK/ROS1 wild-type.
- Specimens were formalin-fixed paraffin-embedded samples previously assessed for ALK and ROS1 rearrangement status.
- All specimens were re-evaluated using the Vysis ALK/ROS1 Dual Break Apart Probe Kit, with FISH images scanned and interpreted remotely.
Main Results:
- The Vysis ALK/ROS1 Dual Break Apart Probe Kit demonstrated high concordance with established methods.
- For ALK rearrangements, 100% concordance was observed in 10 successfully evaluated cases (83% success rate).
- For ROS1 rearrangements, 100% concordance was observed in 6 successfully evaluated cases (75% success rate).
- In wild-type cases, the success rate was 85% (18/21) with 100% concordance.
Conclusions:
- The Vysis ALK/ROS1 Dual Break Apart Probe Kit is a reliable tool for simultaneous detection of ALK and ROS1 rearrangements in NSCLC.
- The kit shows strong analytical performance and concordance with existing FISH assays.
- This validated kit can aid in the clinical screening of NSCLC patients for targeted therapy selection.
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