Undifferentiated carcinoma of the gastrointestinal tract has variable rhabdoid features. Expression of switch/sucrose nonfermenting (SWI/SNF) complex subunits is reportedly lost in a portion of cases; however, the prognostic significance of this loss remains unknown. Herein, 30 undifferentiated carcinoma cases were assessed for the expression of 4 SWI/SNF complex subunits (SMARCB1, SMARCA2, SMARCA4, and ARID1A). Tumor origin sites comprised stomach (40.0%), large intestine (20.0%), small intestine (16.7%), lower esophagus and stomach fundus (13.3%), ileocecal junction (3.3%), rectum (3.3%), and pancreas (3.3%). The tumors were composed of epithelioid neoplastic cells arranged in diffuse solid or discohesive sheets, nests, cords, poor cohesive pseudoglandular, and trabecular patterns. Rhabdoid tumor cells were identified in 66.7% (20/30) of cases. In total, 29/30 (96.7%) showed complete loss of at least 1 SWI/SNF subunit: SMARCA4⁻/SMARCA2⁻ (11), isolated SMARCA4⁻ (2), SMARCA4⁻/SMARCA2 unknown (6), isolated SMARCA2⁻ (7), SMARCA2⁻/ARID1A⁻ (1), and isolated ARID1A⁻ (2). Negative or decreased expression (≤10% positive) of pan-cytokeratin was observed in 58.6% (17/29) of cases. In addition, 66.7% (20/30) of patients were late-stage (III or IV), and 65.2% (15/23) of stage IIB to IV patients succumbed to the disease at a mean clinical follow-up of 12.7 months. Specifically, patients with loss of SMARCA4 expression had the worst overall survival (P=0.028) and disease-free survival (P=0.006) rates, compared with those with SMARCA4 expression. The loss or decreased expression of epithelial markers is thus common in SWI/SNF complex-deficient undifferentiated carcinoma of the gastrointestinal tract, and loss of SMARCA4 correlates with poor prognosis.

胃肠道未分化癌具有不同的横纹肌样特征。据报道，在部分病例中开关/蔗糖非发酵 (SWI/SNF) 复合亚基的表达丢失；然而，这种损失的预后意义仍然未知。在此，评估了 30 个未分化癌病例的 4 个 SWI/SNF 复合亚基（SMARCB1、SMARCA2、 SMARCA4和 ARID1A）的表达。肿瘤起源部位包括胃（40.0%）、大肠（20.0%）、小肠（16.7%）、下食管和胃底（13.3%）、回盲部交界处（3.3%）、直肠（3.3%）和胰腺。 3.3%）。肿瘤由上皮样肿瘤细胞组成，排列为弥漫性实性或不粘性片状、巢状、索状、粘性差的假腺体和小梁模式。66.7% (20/30) 的病例中发现横纹肌样肿瘤细胞。总共，29/30 (96.7%) 表现出至少 1 个 SWI/SNF 亚基完全丧失：SMARCA4 ^- /SMARCA2 ^- (11)，分离的SMARCA4 ^- (2)，SMARCA4 ^- /SMARCA2 未知 (6)，分离的 SMARCA2 ^- (7)、SMARCA2 ^- /ARID1A ^- (1) 和分离的 ARID1A ^- (2)。58.6%（17/29）的病例中观察到全细胞角蛋白表达阴性或降低（≤10%阳性）。此外，在平均临床随访 12.7 个月时，66.7% (20/30) 的患者处于晚期（III 或 IV 期），65.2% (15/23) 的 IIB 至 IV 期患者死于该疾病。具体而言，与SMARCA4表达的患者相比，SMARCA4表达缺失的患者的总生存率 ( P = 0.028) 和无病生存率 ( P = 0.006)最差。因此，上皮标志物的缺失或表达减少在 SWI/SNF 复合体缺陷的胃肠道未分化癌中很常见，并且SMARCA4的缺失与不良预后相关。