Loss of ARID1A, a component of the SWI/SNF chromatin remodeling complex, at the invasion front is related to poor outcomes in oral squamous cell carcinoma

This study aimed to investigate the relationship between loss of AT-rich interactive domain-containing protein 1A (ARID1A) expression and the prognosis of patients with oral squamous cell carcinoma (OSCC). Seventy-five OSCC tissue specimens were immunohistochemically stained with a specific antibody to ARID1A. The immunoreactivity of ARID1A was then correlated with clinicopathological factors, including the prognosis of the patients. Non-tumorous oral squamous cells exhibited nuclear ARID1A staining, whereas the invasive OSCC cells showed different degrees of loss of ARID1A immunoreactivity. Little-to-no ARID1A immunoreactivity was found at the cancer invasion front in 20 of the 75 OSCC tissue specimens, with significant association with unfavorable patient outcomes. Notably, downregulation of ARID1A immunoreactivity was also related to lymphovascular involvement and poor outcome in patients with T1 and T2 OSCC without lymph node metastasis. The results suggest that loss of ARID1A expression at the cancer invasion front might be related to tumor progression in many OSCCs.