Association of expression of siglec-15 with outcomes of neoadjuvant chemoradiotherapy for esophageal squamous cell carcinoma

Sialic acid-binding immunoglobulin-like lectin 15 (siglec-15) is a novel immune checkpoint molecule. A retrospective cohort study at Sun Yat-sen University Cancer Center (Guangzhou, China) investigated the association of expression of siglec-15 with outcomes of neoadjuvant chemoradiotherapy (CRT) for esophageal squamous cell carcinoma (ESCC). Siglec-15 positivity was associated with a higher rate of pCR (52.9% versus 35.0%; p=0.04) and more favorable survival, while PD-L1 positivity was associated with worse survival. Among all phenotypes, the best survival was seen in patients with combined siglec-15 positivity and PD-L1 negativity (‘type II’; 21.5% of patients). The authors conclude that siglec-15 positivity could serve as a novel biomarker to identify ESCC patients who may benefit from immunotherapy combined with CRT.