Related Experiment Video
Updated: Jan 7, 2026
Next Generation Sequencing for the Detection of Actionable Mutations in Solid and Liquid Tumors
Published on: September 20, 2016
Clinicopathological and molecular perspectives on thoracic SMARCA4-deficient undifferentiated tumors and
Sumanta Das1,2, Pallavi Mishra3, Sunita Ahlawat1
1Department of Pathology, Agilus Diagnostics Ltd, Fortis Memorial Research Institute, Gurugram, India.
Abstract:
SMARCA4-deficient tumors of the thoracic cavity represent a newly emerging group of aggressive neoplasms driven by inactivation of the SMARCA4 gene, a key member of the SWI/SNF chromatin remodeling complex. These tumors are broadly classified into thoracic SMARCA4-deficient undifferentiated tumors (SMARCA4-UT) and SMARCA4-deficient non-small cell lung carcinomas (SMARCA4-dNSCLC). Despite some overlap in genomic alterations, especially smoking-related mutations like TP53, KRAS, and KEAP1, these entities differ in histomorphology, immunoprofile, and biological behavior. SMARCA4-UTs are undifferentiated, often rhabdoid in appearance, with loss of epithelial markers and gain of stem cell markers such as SOX2 and SALL4, while SMARCA4-dNSCLCs retain some epithelial differentiation. Radiologically, these tumors often present as large central thoracic masses with high metabolic activity and early metastases. Both tumor types show poor prognosis, with limited response to conventional therapies. Immunotherapy, particularly immune checkpoint inhibitors, shows promise even in PD-L1-negative cases, and emerging epigenetic and molecular targeted therapies are under investigation. It is crucial to distinguish SMARCA4-UT and SMARCA4-dNSCLC by appropriate use of histopathology, immunohistochemistry, and molecular studies, considering the prognosis and treatment response. Our review focuses on the advancement of understanding the clinicopathological spectrum of both entities, their genetic landscape, and current treatment options.
Insights
Newly identified aggressive thoracic SMARCA4-deficient tumors, including SMARCA4-UT and SMARCA4-dNSCLC, require precise diagnosis. Distinguishing these aggressive neoplasms is vital for effective treatment strategies and improved patient outcomes.
Area of Science:
- Oncology
- Genetics
- Pathology
Background:
- SMARCA4-deficient tumors are aggressive thoracic neoplasms driven by SMARCA4 gene inactivation.
- These tumors are classified as SMARCA4-UT and SMARCA4-dNSCLC, exhibiting distinct features despite shared mutations.
Purpose of the Study:
- To review the clinicopathological spectrum, genetic landscape, and treatment options for SMARCA4-deficient thoracic tumors.
- To highlight the importance of differentiating SMARCA4-UT from SMARCA4-dNSCLC for prognosis and therapy.
Main Methods:
- Review of clinicopathological features, histomorphology, immunoprofile, and radiological findings.
- Analysis of genomic alterations, including TP53, KRAS, and KEAP1 mutations.
- Evaluation of current and emerging treatment modalities, including immunotherapy and targeted therapies.
Main Results:
- SMARCA4-UT shows undifferentiated, rhabdoid features with stem cell marker expression.
- SMARCA4-dNSCLC retains some epithelial differentiation.
- Both entities present as large thoracic masses with high metabolic activity and early metastases, indicating poor prognosis.
Conclusions:
- Accurate differentiation between SMARCA4-UT and SMARCA4-dNSCLC is crucial for patient management.
- Despite poor prognosis and limited response to conventional therapies, immunotherapy and targeted agents show promise.
- Further research into genetic drivers and therapeutic strategies is essential for these rare thoracic neoplasms.
