SMARCA4 and undifferentiated carcinoma: Another study reported a rare synchronous malignant gastrointestinal neuroectodermal tumor and SMARCA4-deficient undifferentiated carcinoma in the small intestine that showed complete SMARCA4 deficiency with SMARCA4 frame-shift mutation [c.4882_4886dup(p.Lys1630fs) [30].