Prognostic impact of peritumoral lymphocyte infiltration in soft tissue sarcomas

Tissue microarrays from 80 patients with STS were constructed from duplicate cores of tissue from the tumor and the peritumoral capsule. Immunohistochemistry was used to evaluate the CD3+, CD4+, CD8+ and CD20+ lymphocytes in the tumor and the peritumoral capsule.In univariate analyses, increasing numbers of CD20+ (P = 0.032) peritumoral lymphocytes were associated with a reduced disease free survival (DSS). In multivariate analyses, a high number of CD20+ peritumoral lymphocytes (P = 0.030) in the capsule was an independent negative prognostic factor for DSS. There were no such associations of lymphocyte infiltration in the tumor.A high density of CD20+ peritumoral lymphocytes is an independent negative prognostic indicator for patients with STS. Further research is needed to determine whether CD20 cells in the peritumoral capsule of STS may promote tumor invasion in the surrounding tissue and increase the metastatic potential.Soft tissue sarcomas (STS) are relatively rare heterogeneous malignancies of mesenchymal origin with a high mortality rate. They comprise less than 1% of adult malignancies [1]. Approximately 50% of STS patients will succumb to their disease because of metastasis or local relapse [2]. There are several prognostic factors that determine tumour progression and, ultimately, a patients' fate. These include tumour grade, size, location, depth, histological entity, positive resection margins, and presence of local recurrence [3-9].There are three groups of tumor infiltrating lymphocytes: (a) lymphocytes within cancer cell nests (intratumoral lymphocytes); (b) lymphocytes in the central cancer stroma (stromal lymphocytes), and; (c) lymphocytes present along the invasive margins (peritumoral lymphocytes) [10]. Soft tissue sarcomas are by definition stromal tumores. But from a biological point of view any tissue must have both parenchyma and supporting stroma. For STS it can be both internal tissue and surrounding tissue.In a previous paper we reported