Abstract 93P
Background
The study aims to evaluate the predictive factors of disease relapse in patients with soft tissue sarcoma, focusing on systemic and intratumoral immune status and molecular features, to guide optimal therapeutic planning and prevent disease relapse in patients affected by WDL, DDL, MFS, and UPS.
Methods
The study involved patients with localized WDL, DDL, MFS, or UPS who underwent surgery from 2010 to 2020. FFPE samples of the surgical specimen were collected from 71 patients to perform an RNAseq, among these 47 samples with more than 4M reeds were selected to perform a CIBERSORT analysis to assess tumour-infiltrating immune cells. A differential gene expression analysis was performed comparing G1 VS G2, G2 VS G3, G1 VS G3, Relapse VS No Relapse, Local relapse VS Distant metastasis.
Results
106 patients were included in this single-centre retrospective study, including 31WDL, 30 DDL, 21 MFS, 24 UPS. Patients had better RFS and OS when SSI < 991 (P = 0,0001; P < 0,0001) NLR < 2,5 (P = 0,0006; P =0,0001), PLR < 190 (P = 0,0003; P < 0,0001), LMR ≥2,4 (P = 0,0067; P = 0,0011). Interestingly, patients with naive B-cell fraction (nBC) >3.13% of the total tumor-infiltrating immune cell population had worse RFS (P =0.0181). Furthermore, patients with activated dendritic cells (aDC) >1.02% had better RFS (P = 0.022). Event if not statistically significant, patients with higher histological grading seem to have a higher level of intratumoral monocytes and M2 macrophages. 3 main patient groups have been identified based on the intratumoral immune cell cluster analysis: Cluster A: patient with no disease's relapse and with an higher level of memory B cells and plasma cells; Cluster B: patient with disease's relapse and the highest number of M2 macrophages; Cluster C: high grade patients but with late relapse (>30 months) and the highest level of monocyte (C1) or with just a local relapse and high levels of aDC (C2). The differential expression analysis has revealed five genes (SLC17A8, OR5M8, TIMM8BP2, SLC5A8, and HIST1H4K) that are overexpressed in patients with higher grading and disease recurrence.
Conclusions
The findings of our study, if validated in larger series, may define new biomarkers useful to assess STS's patients risk assessment.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.