Abstract 240P
Background
mRNA testing in NSCLC patients enhances the detection of mutations like ALK, RET, ROS1, and MET exon14 skipping. Due to mRNA's vulnerability to degradation, strict testing standards are required. The current consensus is that samples stored for less than three years are suitable for detection and treatment guidance. However, the suitability of longer-stored samples for mRNA-based fusion testing remains uncertain. This study evaluates the efficacy of AmoyDx 11-gene PCR in detecting fusion genes in long-term preserved FFPE samples.
Methods
We retrospectively analyzed 119 FFPE samples from NSCLC patients collected between 2015 and 2022, which had undergone target sequencing at collection. mRNA was re-extracted and its concentration measured using UV spectrophotometry, followed by AmoyDx 11-gene PCR fusion gene detection.
Results
The study included samples previously identified as ALK fusion (n=22), MET exon14 skipping (n=16), RET fusion (n=17), ROS1 fusion (n=25), and driver gene-negative (n=39). FFPE samples were categorized into three groups based on storage duration: 2-3 years (n=59), 4 years (n=30), and equal or greater than 5 years (n=30). There was no significant difference in mRNA concentration among the three groups, with median concentration of 113.6 ng/μl (2-3 years), 131.9 ng/μl (4 years), and 88.1 ng/μl (≥ 5 years). PCR successfully detected fusion genes in all samples. 79 driver gene-positive patients were identified: ALK fusion (n=23), MET exon14 skipping (n=15), RET fusion (n=18), ROS1 fusion (n=22). The overall concordance rate was 93.3%, with concordance rates for each group are 97.7% (2-3 years), 100% (4 years), and 80.0% (≥ 5 years), respectively.
Conclusions
PCR effectively detects mRNA in long-term preserved FFPE samples, providing valuable variant information for treatment guidance in NSCLC patients, even after extended storage periods.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.