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SWI/SNF complex-deficient undifferentiated/rhabdoid carcinomas of the gastrointestinal tract

Thursday 12 November 2015

Undifferentiated gastrointestinal tract carcinomas are rare highly aggressive neoplasms with frequent but not obligatory rhabdoid features. Recent studies showed loss of SMARCB1 (INI1), a core subunit of the SWI/SNF chromatin remodeling complex, in 50% of tested cases. However, the molecular pathways underlying histologically similar but SMARCB1-intact cases are unknown.

Loss of different components of the SWI/SNF complex other than SMARCB1 can be observed in undifferentiated gastrointestinal carcinomas including novel SMARCA4-deficient and SMARCA2-deficient cases. It underlines the close link between SWI/SNF deficiency and the aggressive rhabdoid phenotype.

Frequent loss of SMARCA2 possibly points to fragility/vulnerability of the SWI/SNF complex as a consequence of lost core subunit SMARCB1. The exact molecular mechanisms underlying co-inactivation of different SWI/SNF subunits merit further investigations.


- SWI/SNF Complex-deficient Undifferentiated/Rhabdoid Carcinomas of the Gastrointestinal Tract: A Series of 13 Cases Highlighting Mutually Exclusive Loss of SMARCA4 and SMARCA2 and Frequent Co-inactivation of SMARCB1 and SMARCA2. Agaimy A, Daum O, Märkl B, Lichtmannegger I, Michal M, Hartmann A. Am J Surg Pathol. 2015 Nov 5. PMID: 26551623