95P The study of immune microenvironment subpopulations in soft tissue sarcomas
Abstract
The tumor microenvironment plays an important role in tumor behavior and the effectiveness of the therapy. However, in soft tissue sarcoma (STS), the impact of the tumor microenvironment has not been practically studied. The aim of the research was to study the effect of the immune microenvironment on the clinical course and prognosis of soft tissue sarcomas. Retrospective research was conducted on 168 soft tissue sarcoma patients who received care at the Republican specialized Scientific and practical Medical Center of Oncology and Radiology of Uzbekistan. Tumor-infiltrating lymphocytes and lymphocyte subpopulations were investigated by immunohistochemical analyses of CD3, CD4, CD8, CD20, CD68. The most common type of cells in the immune microenvironment were macrophages of CD68+ and CD3+ T cells. A multivariate analysis using the Fine & Gray risk regression model with death as a competing event revealed a significant positive correlation between CD68 expression and the risk of local recurrence (p=0.014) regardless of age, resection margins and the presence of B cells. Moreover, the abundance of macrophages was significantly higher in patients older than middle age (p=0.002), while the number of B cells was significantly lower (p=0.013) in elderly patients. As for histological subtypes with a high total number of tumor-infiltrating lymphocytes in general and macrophages in particular, these cells were more often observed in undifferentiated pleomorphic sarcoma and myxofibrosarcoma. The study confirms the high level of CD68 macrophages in soft tissue sarcomas and its adverse effect on the prognosis for local recurrence.