Identification and Treatment of SMARCA4 Deficient Poorly Differentiated Gastric Carcinoma

Loss of expression of the SMARCA4 gene, a subunit of the SWI/SNF complex, has been historically associated with thoracic sarcomas. This loss of expression is extremely rare in gastric cancers, and its role in gastrointestinal tract carcinomas has not been fully elucidated. We report a case of a 73-year-old male with poorly differentiated, SMARCA4-deficient gastric cancer, showing that this immunophenotype is not limited to thoracic sarcomas or advanced-stage tumors. These tumors are often resistant to conventional FLOT chemotherapy and have poor prognoses, necessitating the need for early identification and alternative therapeutic approaches. New therapies such as EZH2 inhibitors and etoposide should be considered in cases where standard treatments are ineffective.