Investigating the prognostic impact of NY-ESO-1 expression and HLA subtypes in metastatic synovial sarcoma.

Background: To better understand the importance of the New York esophageal squamous cell carcinoma 1 (NY-ESO-1) and human leukocyte antigen (HLA) subtypes in treatment decision-making, further investigation of their prevalence and prognostic impact among patients with metastatic synovial sarcoma (mSS) is needed.

Patients And Methods: This was a retrospective clinico-biological cohort study of adults with mSS. Patient data were collected from the French Sarcoma Group NetSARC database and supplemented by electronic medical records. Primary tumor samples were collected and analyzed for NY-ESO-1 expression by immunohistochemistry (IHC) and HLA-A∗02 status by RNA sequencing (RNA-seq). The primary cohort included patients with available primary tumor samples; the impact of a larger sample size was explored by including patients who had either a primary or metastatic sample (termed the exploratory cohort). P values are provided for descriptive purposes.

Results: In 92 patients with primary tumor samples, ∼25% (n = 23) were positive for NY-ESO-1 and HLA-A∗02 expression (dual positive). Among 106 patients with IHC data, 61% (n = 65) were NY-ESO-1 positive, and among 94 patients with RNA-seq data, 45% (n = 42) were HLA-A∗02 positive. The median overall survival (OS) for positive versus negative NY-ESO-1 status was 35.3 and 21.7 months, respectively (unadjusted P = 0.0428). We observed no difference in median OS for HLA-A∗02-positive versus -negative and dual-positive patients versus others (both unadjusted P > 0.05). Multivariate analyses of OS showed no prognostic impact for NY-ESO-1 among primary tumor samples and in the exploratory cohort. However, in the latter we observed an association between NY-ESO-1 expression and OS in the first-line (P = 0.0041) but not in the second-line setting.

Conclusions: The primary tumor cohort showed no association between NY-ESO-1 expression and OS (including stratification by HLA-A∗02 subtype and treatment line) when adjusting for important prognostic factors, possibly due to small sample sizes.