Aberration of ARID1A Is Associated With the Tumorigenesis and Prognosis of Sporadic Nonfunctional Pancreatic Neuroendocrine Tumors

OBJECTIVE The genetic aberrations that underlie chromatin remodeling in sporadic nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) remain largely unknown. Here, we investigated the dysregulation of the switch/sucrose nonfermentable (SWI/SNF) component ARID1A and its correlation with clinicopathological features and prognosis. METHODS We sequenced the exomes of sporadic NF-pNETs. Quantitative real-time polymerase chain reaction and immunohistochemistry were used to determine messenger RNA level and protein expression. RESULTS The sporadic NF-pNETs harbored 264 somatic mutations in 228 different genes, most commonly affecting the SWI/SNF components ARID1B (57.1%) and ARID1A (42.9%). The expression of ARID1A was remarkably downregulated in NF-pNETs and corresponding liver metastases compared with that in normal pancreatic islet tissue. Reduced expression of ARID1A was associated with malignant clinicopathological features (P < 0.05). The loss of ARID1A was related to a high Ki-67 index (P < 0.05). Patients with ARID1A-negative expression had a significantly worse overall survival rate than those with ARID1A-positive expression (P < 0.05). The ARID1A status was an independent predictor of overall survival, and a nomogram integrating ARID1A with clinicopathological features was proposed. CONCLUSIONS The loss of SWI/SNF components ARID1A may be associated with malignant behaviors and an unfavorable prognosis. Aberrations of ARID1A may contribute to tumorigenesis and metastasis in sporadic NF-pNETs.