CD45RO-Positive Memory T-Cell Density in the Tumoral Core and Invasive Margin Predict Long-Term Survival in Esophageal Squamous Cell Carcinoma.

Abstract

The association between tumor-infiltrating lymphocytes and tumor immunity has long been recognized. Among T-cell types, CD45RO-positive memory T cells (CD45RO⁺) are reported to correlate with survival in several cancer types, but clinical evidence is lacking in esophageal squamous cell carcinoma (ESCC). In surgical specimens from 162 preoperatively untreated patients, immunohistochemistry for CD45RO was performed to evaluate the density of CD45RO⁺ in the tumor core (CT) and invasive margin (IM) using an auto-count method. Patients were classified into high- versus low-CD45RO⁺ groups based on CD45RO⁺ density in CT and IM separately and combined. The relationship between CD45RO⁺ density and clinicopathological factors, including prognosis, was evaluated. Average CD45RO⁺ density was 133/mm² in CT and 372/mm² in IM. No significant differences in clinicopathological factors according to high- versus low-CD45RO⁺ scores were identified. Using CT scores, the CD45RO⁺-high group had a better 5-year overall survival (OS) rate (77.2% vs. 54.7% CD45RO⁺-low, P = 0.0433), but OS rates did not differ statistically between the two groups by IM scores (75.7% vs. 50.3%, P = 0.0576). Using immunohistochemical scores for CT+IM, the survival difference was significant, with a 5-year OS rate of 73.7% for the CD45RO⁺-high group versus 46.3% for the CD45RO⁺-low group (P = 0.0141). Multivariate analysis identified CD45RO⁺ CT+IM density as an independent prognostic variable in OS (hazard ratio 2.27, 95% confidence interval 1.43-3.62, P = 0.0006). Density of CD45RO⁺ expression in the CT and IM might be a predictor of long-term survival in ESCC.