Cathepsin K immunostaining pattern in lymph node metastases of OTSCC is similar to the primary tumor.

<p>Metastatic carcinoma cells were identified with pancytokeratin staining (A–B), followed by cathepsin K staining of the paired primary OTSCC (C) and lymph node metastases (D) (n = 10, the paired sections were taken from the same patient). The arrows indicate similar cathepsin K staining patterns in both the primary tumor and in the lymph node metastases. Lymph nodes without metastases contain some cathepsin K positive cells (E), but the stromal reaction drastically changes in the presence of cathepsin K positive OTSCC cells (F). Scale bars 200 µm.