Is minimal residual lymph node disease in papillary thyroid cancer of prognostic impact? An analysis of the epithelial cell adhesion molecule EpCAM in lymph nodes of 40 pN0 patients

Immune Escape Mechanism is Impaired in the Microenvironment of Thyroid Lymph Node Metastasis

We previously identified the infiltration of CD8+ lymphocytes and COX2 expression as an independent factor of risk for recurrence in papillary thyroid carcinoma (PTC) patients. However, the presence of lymph node (LN) metastasis at diagnosis lost its significance in a multivariate model analysis. These results encouraged us to compare the immune cells arrangement in the microenvironment of the LN metastasis and the primary tumor. We studied 104 consecutive PTC patients. Tissue specimens of both primary tumor and LN metastasis at the time of diagnosis were available in 19 out of them. These 19 patients were followed up for 32 to 81 months (64.7 ± 47.5 months). Immune cell markers were investigated using immunohistochemistry and included tumor infiltrating lymphocytes subsets such as CD3, CD4, CD8, CD16, CD20, CD45RO, GRANZYME B, CD69, and CD25. We also investigated the expression of COX2 in tumor cells. Paired t test showed an increase of GRANZYME-B+ lymphocytes density in LN metastasis compared to the corresponding primary tumor, suggesting that LN metastasis is enriched with activated immune cells. In addition, we observed a decrease in COX2 expression levels in LN metastasis compared to the corresponding primary tumors, reinforcing the idea that the immune escape mechanism is impaired in the microenvironment of thyroid LN metastasis. In conclusion, our data demonstrated that the microenvironment of PTC LN metastasis present features that favor an anti-tumor immune response. This may help to explain why the presence of LN metastasis at diagnosis is not a good predictor of PTC patients' survival or disease progression.

EpCAM Expression in Lymph Node Metastases of Urothelial Cell Carcinoma of the Bladder: A Pilot Study

In this retrospective pilot study, the feasibility of the epithelial cell adhesion molecule (EpCAM) as an imaging target for lymph node (LN) metastatic disease of urothelial cell carcinoma (UCC) of the bladder was investigated. LN metastases and LNs without metastases of patients who underwent pelvic lymph node dissection because of muscle invasive bladder cancer (MIBC) were used. Primary tumors of the same patients were used from cystectomy specimen, transurethral resections, and biopsies. A pathologist, blinded to clinical data, scored EpCAM immunoreactivity. This method determines a total immunostaining score, which is the product of a proportion score and an intensity score. EpCAM expression was observed in 19/20 (95%) LNs with UCC metastases and in 11/12 (92%) of the primary tumors. EpCAM expression was absent in 14/14 (100%) LNs without metastases. Median EpCAM expression (TIS) in LN metastases was 5 (IQR 2.0–8.0) and in the primary tumors 6 (IQR 2.3–11.0). Based on the absence of staining in LNs without metastases, EpCAM show high tumor distinctiveness. EpCAM seems to be a feasible imaging target in LN metastases of UCC of the bladder. Pre- and perioperative visualization of these metastases will improve disease staging and improve the complete resection of LN metastases in MIBC.