CD3+T-lymphocyte infiltration is an independent prognostic factor for advanced nasopharyngeal carcinoma

Abstract

Background: Locally advanced nasopharyngeal carcinoma (LA-NPC) is a relatively rare disease in the west but more common in East Asia and areas of the Middle East like Saudi Arabia. Despite the advances in radiation therapy techniques, some patients relapse after treatment. In the coming era of cancer immunotherapy, prognostic factors for LA-NPC need to be further defined using immune-relevant markers. Several markers are available; however, the most robust and accessible/affordable marker is not well-defined.

Methods: Retrospectively, tumor-infiltrating lymphocytes (TIL), their subsets as well as tumoral PD-L1 expression were analyzed in tumor tissues from 63 LA-NPC patients treated with platinum-based concurrent chemo-radiotherapy (CCRT) in addition to 20 cases with metastatic (MET) disease. Immunostaining was done using a validated and fully automated system. Scoring was done by two independent pathologists and results were compared.

Results: There was no statistical difference between LA-NPC and MET disease in terms of CD3+, CD8+ TIL infiltration, or tumoral PD-L1 expression. In LA-NPC, low CD3+ TIL infiltration highly correlated with shorter disease-free survival (DFS, HR = 8.5, p = < 0.001) and overall survival (OS, HR = 13, p = 0.015) with substantial agreement between scoring pathologists. A similar correlation was found between low CD8+ TIL and survival. Correlation of total TIL was significant with DFS (HR = 4.0, p = 0.008), borderline with OS and the correlation was dependent on the scoring pathologist. Having histological WHO type I&II correlated significantly with shorter DFS (HR 4.03, p = 0.008) and low CD3+ TIL (p = 0.009). Subgroup analysis of LA-NPC that included undifferentiated type (WHO type III) cases only (n = 58), showed a strong correlation between low CD3+ TIL and shorter DFS (HR = 7.2, p = < 0.001) and OS (HR = 17.3, p = 0.008). PD-L1 was expressed in 72% of type III LA-NPC cases while lacking PD-L1 expression correlated with shorter OS (HR = 6.1, p = 0.031). Patients with a combination of low CD3+ TIL and lack of PD-L1 expression had the worst OS (p < 0.001).

Conclusions: CD3+ TIL is promising as a robust and independent prognostic marker for DFS and OS of LA-NPC patients treated with platinum-based CCRT. We would suggest the use of CD3 + TIL as a stratifying factor for LA-NPC, which warrants further validation in prospective trials.

Keywords: CD3; Chemo-radiotherapy; Immune infiltrate; Lymphocytes; Nasopharyngeal carcinoma.

Fig. 1

Immune cell infiltration and PD-L1 expression in nasopharyngeal carcinoma. Representative images at × 200 magnification of nasopharyngeal carcinoma tissue sections showing a T-lymphocytes and their subsets b Tumor cells expression of PD-L1. The red color represents CD3 staining while CD8, FOXP3 (nuclear), PD-1 and PD-L1 are brown. Inset in the FOXP3 staining image shows a higher magnification image (× 530) to illustrate the membranous red CD3 staining and nuclear brown FOXP3 staining as a typical marker for T-reg cells. *Images of negative controls are shown in b, i.e., sections incubated with antibody diluent alone without primary antibody

Fig. 2

Relation of total, CD3+ and CD8+ TIL to survival of LA-NPC patients (n = 63). Kaplan–Meier survival curves showing a disease-free survival (DFS) and b overall survival (OS) of patients in relation to their CD3+ TIL infiltration, CD8+ TIL infiltration or total TIL (assessed from H&E sections) infiltration. Statistical significance was calculated using log-rank test

Fig. 3

Relation of total, CD3+ and CD8+ TIL to survival of subgroup of LA-NPC patients with undifferentiated histological WHO type III (n = 58). Kaplan–Meier survival curves showing a disease-free survival (DFS) and b overall survival (OS) of patients in relation to their CD3+ TIL infiltration, CD8+ TIL infiltration or total TIL (assessed from H&E sections) infiltration. Statistical significance was calculated using log-rank test