2024 World Conference on Lung Cancer (WCLC) - ePosters-EP.06G.08 Clinicopathologic and Molecular Features of SWI/SNF-Deficient Thoracic Tumors

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This study investigates the clinicopathologic and molecular characteristics of SWI/SNF-deficient thoracic tumors, focusing particularly on SMARCA4-deficient undifferentiated tumors (SD-UT) and SMARCA4-deficient non-small cell lung cancers (SD-NSCLC). The analysis includes 485 thoracic tumor cases, out of which 47 exhibited SMARCA4 deficiency. These tumors were categorized into well to moderately differentiated SD-NSCLC, poorly differentiated SD-NSCLC, and SD-UT tumors. The study highlights that males over 50 years old are predominantly affected by these tumors, suggesting a potential link between gender and tumor incidence.<br /><br />Next-generation sequencing (NGS) revealed a high frequency of KRAS mutations in SD-UTs, indicating that combined mutations in SMARCA4 and KRAS may hinder tumor differentiation. Classification of tumors is assisted by immunohistochemistry; particularly when AE1/AE3 is negative or weakly positive, the tumor is likely categorized as SD-UT, which generally has a poorer prognosis.<br /><br />Immunotherapy has shown promising outcomes, mainly for patients with poorly differentiated tumors. The presence of fewer regulatory T-cells is associated with worse prognoses, suggesting potential diagnostic and therapeutic avenues.<br /><br />The study underscores the utility of immunoreactivity scoring (IRS) systems aided by software such as X-tile for prognostic evaluation, establishing definitive cutoff values for SMARCA4 and AE1/AE3 expressions. The findings indicate that patients with SMARCA4-deficient non-small cell lung cancer (SD-NSCLC) tend to have a better prognosis compared to those with undifferentiated tumors.<br /><br />Overall, the results provide new insights into the diagnosis, prognosis, and treatment of SWI/SNF-deficient thoracic tumors, emphasizing the potential of immunotherapy and the importance of specific molecular markers in clinical assessments.

Asset Subtitle

Jia Feng

Meta Tag

Speaker Jia Feng

Topic Pathology and Biomarkers

Keywords

SWI/SNF-deficient

SMARCA4-deficient

thoracic tumors

non-small cell lung cancer

KRAS mutations

immunohistochemistry

immunotherapy

prognostic evaluation

molecular markers

clinicopathologic characteristics