Virtual Library
Start Your Search
Angelo Sparaneo
Author of
-
+
P2.14 - Targeted Therapy (ID 183)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Targeted Therapy
- Presentations: 2
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
-
+
P2.14-14 - Comparison of Molecular Testing Modalities for Detection of NRG1 Rearrangements in Invasive Mucinous Adenocarcinoma (ID 2179)
10:15 - 18:15 | Author(s): Angelo Sparaneo
- Abstract
Background
The NRG1 (Neureguline-1) fusion gene has been recently described as a new molecular feature of non small cell lung cancer (NSCLC), strictly related to invasive mucinous adenocarcinoma (IMA) subtype. Despite of NRG1 fusion partners, all Nrg1 chimeric ligands were predicted to retain the EGF-like domain of the wild-type NRG1 III-β3 isoform that produces oncogenic signals through ErbB2-ErbB3 heterodimers and leads to phosphorylation of ErbB3. To date, the NRG1 fusions were quite exclusively identified by RNA sequencing and only in few cases confirmed by fluorescent in situ hybridization (FISH) analysis, mainly due to the cellular features of IMA subtypes that produce interference in fluorescent signals detection. An accurate detection of NRG1 rearrangement/fusions in clinical tumor samples is actually demanded. In this study we compared the performance of two molecular testing approaches to detect NRG1 breaks in paraffin embedded formalin fixed (FFPE) IMA lung tissues.
Method
A total of 19 lung FFPE IMAs were screened by immunohistochemistry (IHC) to evaluate the expression of phosphorylated-ErbB3 (pErbB3) receptor. Samples positive for pErbB3 staining were tested by using by break-apart FISH to detect putative NRG1 rearrangements and RNA-targeted next generation sequencing (NGS) to identify fusion variants.
Result
Eleven cases showed an increased expression of pErbB3 in cancer cells compared to the adjacent non-involving bronchial epithelium which demonstrated a basal level staining of the protein. pErbB3 positive cases were investigated by FISH and showed <15% of rearranged nuclei (range 17-47%, mean 29%). In addition to the canonical signal split pattern, the FISH NRG1 assay reveals that cells also showed rearrangement patterns in form of isolated 3’ signals, thus indicating a strength analogy with ALK and ROS1 fusions, where a 5’ gene deletion was frequently observed. CD74-NRG1 fusion variant was identified by NGS analysis in four cases, whereas in three cases a 3’/5’ NRG1 imbalance was detected. For both approaches, we identified assay characteristics that likely contributed to false-negative results.
Conclusion
Our investigations confirm the usefulness of IHC/FISH combined approach for NRG1 broken tumors identification, but also highlight the crucial role of NGS to identify NRG1 functional chimeric transcripts. Such combined molecular testing should enhance the selection of NRG1-positive patients to include in clinical trials with specific compounds designed to inhibit the RTK downstream signal.
-
+
P2.14-32 - Epigenetic Silencing of SPARC in NSCLCs (ID 2345)
10:15 - 18:15 | Author(s): Angelo Sparaneo
- Abstract
Background
The silencing of SPARC gene through methylation of its promoter region has been commonly observed in many solid tumors and is frequently associated with tumor progression and an aggressive clinical outcome. At present, the data concerning the mechanisms of SPARC deregulation in lung cancer are almost incomplete and correlation analysis with disease clinical course and specific therapeutic strategies is ongoing. Here we present the epigenetic profile of SPARC gene promoter in a collection of NSCLC cell lines and tissue samples and assess its prognostic value in surgical NSCLC resected patients.
Method
Four cell lines (3 adenocarcinoma, ADC and 1 large cell carcinoma, LCC) and 66 primary NSCLC tissues from surgically resected patients (30 squamous cell carcinoma, SqCC and 36 ADC) and 11 lung non-neoplastic tissues were epigenetically scanned. Promoter methylation analysis was performed using a quantitative methylation specific PCR assay in real-time (QMSP). The downstream effect of epigenetic silencing was also investigated in A549 and H1573 NSCLC cell lines by 5-Aza-2’-deoxycytidine treatment to demonstrate if the demethylating agent was able to restore SPARC mRNA expression levels. SPARC methylation levels were correlated with clinicopathological features.
Result
A tumor-specific DNA methylation of the SPARC gene promoter region was found as a specific feature of NSCLC (p=00643 Mann-Whitney test) and was also observed in all cell lines analyzed. In particular, it was detected in 56% of SqCCs (20/36) and 64% of ADCs (19/30), with SqCC showing the highest levels of methylation. Overall, we found promoter hypermethylation in 59% of NSCLCs. Moreover, a direct correlation with mRNA levels was confirmed by in vitro 5-azacytidine treatment. In SqCCs, SPARC methylation levels correlated with a negative prognosis (p<0,012 Supremum Test for Functional Form, HR=1,93; 95%CI).
Conclusion
Our results further suggest that epigenetic deregulation of the SPARC gene could be involved in the cancerogenesis of NSCLC. Additional studies on a larger cohort of NSCLCs and correlation with clinic-pathological features may contribute to disease progression prediction and new molecular basis to codify the response to therapy in lung cancer patients.
