Abstract 1893
Background
The SMARCA4 catalytic ATPase, can be inactivated by several types of genomic alterations (GA) in NSCLC. SMARCA4 deficient (d) NSCLC is an aggressive subtype of primary lung adenocarcinoma that is often confused with metastatic disease to the lung.
Methods
From a series of 40,319 clinically advanced NSCLC, 2,840 (7%) SMARCA4d and 37,479 (93%) SMARCA4i cases underwent hybrid capture-based CGP using FFPE material. Microsatellite instability (MSI) was determined on 114 loci and tumor mutational burden (TMB) and (mutations (mut) per/ Mb) was determined on 1.1 Mbp of sequenced DNA. PD-L1 expression was measured by IHC (Dako 22C3).
Results
SMARCA4d was inactivated by short variant base substitutions and truncations (88%), deletions (9%), duplications (1%), rearrangement/fusions (1%). SMARCA4d patients were slightly younger and featured significantly fewer females (Table). At 3.2 vs 5.6 GA/tumor, SMARCA4d tumors had significantly fewer driver-type GA than SMARCAi tumors. Although non-targetable GA in TP53 and KRAS were similar, SMARCA4d cases features significantly lower frequencies of the EGFR and PIK3CA SV targets and fusions in ALK, ROS1 and NTRK1-3 genes. In contrast, SMARCA4d tumors had a significantly higher frequency of STK11 mutations while also having a higher median TMB and greater proportion of cases with > 10 and > 20 mut/Mb. CDK4/6 GA were more frequent in the SMARCA4i cases.Table:
1583P
SMARCA4 Deficient NSCLC | SMARCA4 Intact NSCLC | Significance | |
---|---|---|---|
Cases | 2,840 | 37,479 | |
% Male/female | 57/43 | 49/51 | P < 0.0001 |
Median age | 64 | 67 | NS |
GA/tumor | 3.2 | 5.6 | P < 0.0001 |
TP53 | 70% | 64% | NS |
KRAS | 28% | 30% | NS |
EGFR | 7% | 18% | P < 0.0001 |
STK11 | 34% | 13% | P < 0.0001 |
PIK3CA | 5% | 10% | P < 0.0001 |
RB1 | 6% | 8% | NS |
MET | 4% | 5% | NS |
BRAF | 4% | 5% | NS |
ERBB2 | 6% | 4% | NS |
CDK4 | 2% | 4% | P < 0.0001 |
CDK 6 | 2% | 2% | NS |
ALK ROS1 NTRK1/3 | 2% | 5% | P < 0.0001 |
PD-L1 (CD274) amp | 1% | 1% | NS |
PD-L1 Low | 26% | 27% | NS |
PD-L1 High | 18% | 29% | P < 0.0001 |
Median TMB (mut/Mb) | 12.2 | 6.1 | P < 0.0001 |
TMB > 10 mut/Mb | 60% | 35% | P < 0.0001 |
TMB > 20 mut/Mb | 27% | 10% | P < 0.0001 |
MSI High | 0.8% | 0.2% | NS |
Conclusions
SMARCA4d NSCLC is characterized by pleomorphic histology, TTF1- IHC and significant reduction in targetable driver mutations in genes such as EGFR, ALK, ROS1 and NTRK1-3. Despite new evidence that SMARCA4d tumors can respond to cell cycle inhibitors such as palbociclib, the CDK4/6 mutation frequencies is not increased in this tumor subset. Higher TMB levels in SMARCA4d NSCLC suggests strong potential for immunotherapy benefit, but the significantly enriched STK11 GA frequency may reduce overall response rates to checkpoint inhibitors.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Foundation Medicine.
Funding
Foundation Medicine.
Disclosure
D. Lin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J.A. Elvin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J. Vergilio: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J.K. Killian: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. N. Ngo: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. S. Ramkissoon: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. E. Severson: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. A. Hemmerich: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. D. Duncan: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. C. Edgerly: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. S.M. Ali: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. A.B. Schrock: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J. Chung: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. E.S. Sokol: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. P. Reddy: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. K. McGregor: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. V.A. Miller: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. B.M. Alexander: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J.S. Ross: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. All other authors have declared no conflicts of interest.
Resources from the same session
2728 - MicroRNA expression and DNA methylation profiles do not distinguish between primary and recurrent well-differentiated liposarcoma
Presenter: Melissa Vos
Session: Poster Display session 1
Resources:
Abstract
3197 - Genomic Alterations, Tumor Mutation Burden and Prognosis of Chinese Cardiac Sarcoma Patients
Presenter: Na Zhu
Session: Poster Display session 1
Resources:
Abstract
4214 - Evaluation of a peptide-conjugated alkylator melflufen in osteosarcoma preclinical models
Presenter: Konstantin Byrgazov
Session: Poster Display session 1
Resources:
Abstract
2654 - Expression analysis of NHEJ and HR genes in Ewing sarcomas: indications of DSB repair dysfunction
Presenter: Anastasios Kyriazoglou
Session: Poster Display session 1
Resources:
Abstract
4383 - Epidemiology of Synovial Sarcoma in EU28 countries
Presenter: Nedra Joseph
Session: Poster Display session 1
Resources:
Abstract
1937 - Resection Of High-Grade Large Soft Tissue Sarcoma With Adequate Wide Margin Can Lead To Good Local Control Without Adjuvant Radiotherapy
Presenter: Toshiyuki Kunisada
Session: Poster Display session 1
Resources:
Abstract
3757 - Influence of eribulin on proliferation, migration and invasion properties of leiomyosarcoma cell line models
Presenter: Marta Mendiola
Session: Poster Display session 1
Resources:
Abstract
1040 - EREMISS: Efficacy of regorafenib (REG) as maintenance therapy in non-adipocytic soft tissue sarcomas (STS) having received 1st-line doxorubicin-based chemotherapy (Doxo-CT)
Presenter: Nicolas Penel
Session: Poster Display session 1
Resources:
Abstract
1048 - A Phase 2 biomarker-driven study evaluating the clinical efficacy of an MDM2 inhibitor, milademetan, in patients with intimal sarcoma, a disease with a high unmet need
Presenter: Kan Yonemori
Session: Poster Display session 1
Resources:
Abstract
1511 - A pilot study of oral paclitaxel (ORAXOL) in subjects with cutaneous angiosarcomas (KX-ORAX-010)
Presenter: Herbert Loong
Session: Poster Display session 1
Resources:
Abstract