Virtual Library
Start Your Search
Ruth Román
Author of
-
+
P1.01 - Advanced NSCLC (ID 158)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall
-
+
P1.01-56 - Increased ROS1 and RET Transcripts in Fusion-Negative NSCLC Patients (ID 2477)
09:45 - 18:00 | Author(s): Ruth Román
- Abstract
Background
Fusion involving anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET) or v-ros UR2 sarcoma virus oncogene homolog 1 (ROS1) occur in non-small cell lung cancers (NSCLC) and are important biomarkers for targeted therapies. However, little is known about the RNA expression levels of these genes regardless of fusions.
Method
We used a custom nCounter panel (NanoString Technologies) designed to detect several genetic alterations, including fusions and mRNA expression levels of ALK, ROS1 and RET in formalin-fixed paraffin embedded (FFPE) samples. RNA was purified from NSCLC tumor samples and analyzed with the custom panel. The counts corresponding to the 3’ probes were normalized using the geometrical mean of the housekeeping genes and then added to evaluate total mRNA expression levels. Cut-off values for overexpression were established as the average counts for each gene plus two times the standard deviation.
Result
A total of 400 stage III-IV NSCLC patients (p) from two different institutions were retrospectively analyzed. Overexpression of ALK was found in 55 p (13.8%). Of them, 48 (87%) were also positive for EML4-ALK fusions. One ALK-translocated patient with low levels of ALK mRNA expression did not respond to therapy. Fifteen p (3.8%) showed ROS1 overexpression. In contrast with ALK, only three of them (15%) had a concomitant ROS1 fusion. Among the remaining 12 patients overexpressing ROS1, four were ALK positive, five harbored mutations in EGFR and three were non-smoker females with no known drivers. Regarding RET, high expression levels were found in 14 p (3.5%) and only one of them showed a RET fusion (7%). Among the remaining 13 p, three presented neuroendocrine features and seven were smoker or ex-smoker without other known drivers.
Conclusion
Overexpression of ALK mRNA in NSCLC is associated with EML4-ALK translocations. In contrast, a significant number of fusion negative patients show high ROS1 or RET mRNA levels. Further research is warranted to determine the clinical relevance of this finding.
-
+
P2.01 - Advanced NSCLC (ID 159)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
-
+
P2.01-56 - Copy Number Gains (CNGs) of Clinically Relevant Genes in Advanced NSCLC Patients (ID 2519)
10:15 - 18:15 | Author(s): Ruth Román
- Abstract
Background
Somatic copy number variations (CNV; i.e. amplifications and deletions) have been implicated in the origin and development of multiple cancers and some of these aberrations are designated targets for therapies, such as amplified ERBB2 in breast cancer. In the case of NSCLC patients, MET alterations are receiving increasing attention as targets in precision medicine, and several clinical trials of anti-MET agents are ongoing. Routine testing for these potential targets on formalin-fixed paraffin embedded (FFPE) samples is mainly carried out by in-situ hybridization (FISH) approaches covering only a single gene of interest. Although this methodology is still the gold standard of CNV detection, it presents several drawbacks. Here we aimed to determine the potential of next generation sequencing (NGS) to simultaneously determine CNGs across many in FFPE samples
Method
FFPE biopsies from 140 stage IIIb-IV NSCLC patients (p) of our institution were prospective tested. Of them, 110 corresponded to samples at diagnostic and 30 after progression to targeted therapies. DNA was purified submitted to NGS using the 16-gene QIAact Lung Panel (Genereader®, Qiagen). Coverages for the genes analyzed were normalized using the total coverage of the panel. Cut-off values for CNVs were established as the average normalized coverage for each gene plus two times the standard deviation. Representative samples were analyzed by FISH
Result
Validation analyses in 8 cell lines showed 100% concordance between FISH and NGS for detection of EGFR, MET and ERBB2 amplifications. Among the 140 NSCLC p, MET was the gene showing a higher frequency of CNGs, followed by PIK3CA, NRAS, EGFR and KRAS (Table 1). In contrast, only one p was found to harbor a ROS1 CNG. Among the 17 samples with MET CNG (12%), 6 corresponded to p progressing to targeted therapies. In addition, 8 of the 17 samples with MET CNGs were submitted to FISH, 6 of them were positive and the remaining 2 samples had copy numbers higher than 3.5 by this technique. In the case of EGFR, CNGs were associated with sensitizing mutations, with 5 samples showing both alterations concomitantly. In contrast, PIK3CA, NRAS, ALK, BRAF, HER2, PDGFRA, KIT and MET CNGs were not associated with mutations (Table 1).
n CNG
%
n MUTANT
MET
17
12.1
0
PIK3CA
12
8.6
0
NRAS
10
7.1
0
EGFR
10
7.1
5
KRAS
10
7.1
2
ALK
8
5.7
0
BRAF
8
5.7
0
ERBB2
8
5.7
0
PDGFRA
6
4.3
0
KIT
6
4.3
0
ROS1
1
0.7
0
Conclusion
CNGs in clinically relevant genes are present in a significant percentage of advanced NSCLC patients and, except in the case of EGFR, are not associated with driver mutations. Further research is warranted to determine the clinical implications of this finding.
