Immunohistochemical Evaluation of Candidate Biomarkers for Fluorescence-Guided Surgery of Myxofibrosarcoma Using an Objective Scoring Method

Abstract

Introduction: Myxofibrosarcoma (MFS) is the most common soft-tissue sarcoma subtype in elderly patients. Local recurrence (LR) remains a major concern as the lack of intraoperative guidance and an infiltrative growth pattern with long, slender tails hamper surgeons’ ability to achieve adequate resection margins for MFS. Fluorescence-guided surgery (FGS) could overcome this concern by delineating tumor tissue during surgery. One of the most important steps to successful FGS is to define a tumor-specific biomarker that is highly overexpressed in tumor tissue while low or absent in adjacent healthy tissue. The aim of this study is to evaluate the expression of eight previously selected promising biomarkers for FGS in MFS tissue samples with adjacent healthy tissue using immunohistochemistry (IHC). Methods: The following eight biomarkers were stained in seventeen paraffin-embedded MFS samples: tumor endothelial marker-1 (TEM-1, also known as endosialin/CD248), vascular endothelial growth factor receptor-1 (VEGFR-1, also known as Flt-1), vascular endothelial growth factor receptor-2 (VEGFR-2, also known as Flk1), vascular endothelial growth factor-A (VEGF-A), epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), platelet derived growth factor receptor-α (PDGFR-α), and cluster of differentiation 40 (CD40, also known as TNFRSF5). A pathologist specializing in sarcoma annotated the margin between the tumor and adjacent healthy tissue in each MFS tissue sample. Subsequently, we used an objective IHC scoring method to assess and compare the difference in staining intensity between the tumor and adjacent healthy tissue, which is crucial for the use of FGS. Results: TEM-1, VEGF-A, and PDGFR-α stained all MFS tumors, while the other biomarkers did not show expression in all MFS tumors. Ultimately, TEM-1 was identified as the most suitable biomarker for FGS in MFS based on higher tumor-to-background (TBR) staining intensity compared to VEGF-A and PDGFR-α, regardless of preoperative therapy. Conclusion: TEM-1-targeted FGS tracers should be further investigated to optimize MFS treatment.

Evaluation of Potential Targets for Fluorescence-Guided Surgery in Pediatric Ewing Sarcoma: A Preclinical Proof-of-Concept Study

“…In addition, comparing IHC stainings for the purpose of FGS should be undertaken with caution due to the variability of results depending on decalcification methods and the type of antibodies, dilutions, epitopes, clones, or staining protocols used [38]. Moreover, the IRS scoring can be seen as subjective due to intra-and interobserver variability, and objective scoring methods using semi-automated imaging software such as ImageJ or QuPath could improve the quality of this study [39][40][41]. However, evaluation with QuPath required a test and validation set, which was unfeasible for our small cohort of ES samples.…”

Cross-species evaluation of fibroblast activation protein alpha as potential imaging target for soft tissue sarcoma: a comparative immunohistochemical study in humans, dogs, and cats

“…Tumor endothelial marker 1 (TEM1) and vascular endothelial growth factor A (VEGF A) were identified as the targets with the highest TASC scores ( 62 ). In addition, in MFS, TEM1 showed the highest tumor-to-background ratios assessed using IHC ( 63 ). VEGF A is also expressed in normal vasculature, and overexpression in the peritumoral tissue was detected in a few MFS cases ( 25 ).…”

“…First, our results are solely based on the IHC of FFPE tissue samples, and no additional protein analyses such as Western blotting or PCR were included to confirm and further quantify the FAP expression. However, IHC staining of tumor tissue is a validated and commonly used technique to evaluate the degree of biomarker expression and has already been used for target screening in STS ( 25 , 33 , 62 , 63 ). In contrast, there are currently no scores for imaging targets available based on PCR or sequencing data.…”

Biology and Management of High-Grade Myxofibrosarcoma: State of the Art and Future Perspectives

“…Immunostainings for S-100 protein and desmin are typically negative. Recent immunohistochemical studies demonstrate a strong expression of tumor endothelial marker 1 (TEM-1), also known as endosialin/CD248, in 88.2-100% of cases and suggest that TEM1 may be a suitable biomarker for fluorescence-guided surgery in MFS [57,58]. Most recently, we reported that glucose transporter 1 (GLUT-1) expression was seen in all MFS cases examined and suggested that GLUT-1 might be useful for the differential diagnosis of MFS and nodular fasciitis [59].…”