A Consensus Diagnosis Utilizing Surface KI-67 Expression as an Ancillary Marker in Low-Grade Dysplasia Helps Identify Patients at High Risk of Progression to High-Grade Dysplasia and Esophaegal Adenocarcinoma

Esophageal adenocarcinoma (EAC) develops in a step-wise manner, from low-grade dysplasia (LGD) to high-grade dysplasia (HGD), and ultimately to invasive EAC. However, there remains diagnostic uncertainty about LGD and its risk of progression to HGD/EAC. The aim is to investigate the role of Ki-67, immune-histochemical marker of proliferation, surface expression in patients with confirmed LGD, and risk stratify progression to HGD/EAC. A retrospective cohort study was conducted. Patients with confirmed LGD and indefinite for dysplasia (IND), with a mean follow-up of ≥1 year, were included. Pathology specimens were stained for Ki-67 and analyzed for evidence of surface expression. Our results reveal that 29% of patients with confirmed LGD who stained positive with Ki-67 progressed to HGD/EAC as opposed to none (0%) of the patients who stained negative, a statistically significant result (P = 0.003). Similarly, specimens from patients with IND were stained and analyzed revealing a nonsignificant trend toward a higher rate of progression for Ki-67 positive cases versus Ki-67 negative, 30% versus 21%, respectively. Ki-67 expression by itself can identify patients with LGD at a high risk of progression.