[SMARCA4-deficient thoracic tumors: A new entity]

Abstract

A growing number of studies suggest a tumor suppressor role for the SWI/SNF complex involved in the remodeling of chromatin. Alterations of this complex have been found in many tumors of different origins, with topographic, morphologic and phenotypic diversity. Notably, they define 2 types of thoracic tumors: SMARCA4-deficient non-small cell lung carcinoma and SMARCA4-deficient sarcoma. Some clinical features appear to be common to both, such as intrathoracic localization, smoking exposure, male predominance and poor prognosis. However, the histological distinction between these two entities is sometimes difficult and it is not excluded that these entities belong to the same tumor spectrum with different degrees of differentiation. The therapy of these tumors is not yet codified. These tumors do not seem associated with oncogenic driver mutations allowing the prescription of targeted therapy, but immunotherapy has been shown to be effective in rare reported cases. More specific treatments using EZH2 inhibitors also seem promising in SMARCA4 deficient sarcomas.

Keywords: BRG1; CBNPC; NSCLC; SMARCA4; SWI/SNF complex.