Identification of Cancer-Associated Fibroblasts in Metastatic Lymph Nodes of Colorectal Carcinoma

Cancer-associated fibroblasts (CAF) are a heterogeneous group of tumor microenvironment cells that are barely studied in metastatic lymph nodes. The presence of CAF in regional metastases of colorectal cancer was assessed by using SMA, PDGFRb, and POD markers; the obtained subpopulations were compared with the primary tumor. A total of 26 cases of colon adenocarcinoma with metastases to regional lymph nodes were studied. Duplex immunohistochemical detection (POD+SMA and PDGFRb+SMA) was carried out by the immunohistochemical method. In most cases, POD was absent in metastases (65.4%) and PDGFRb was present (88.5%). The POD and PDGFRb staining in the invasive edge of the tumor did not correlate with metastasis. Attention was drawn to the absence of POD and PDGFRb reactions in a blood vessel embolus, as well as to negative PDGFRb in metastasis in the presence of pronounced PDGFRb in the primary tumor in patients after neoadjuvant therapy.