Immunohistochemical Assessment of the Tumour-Associated Epitopes CD44v6 and E48 in Tumour-Free Lymph Nodes from Patients with Squamous Cell Carcinoma in the Head-Neck Region

We examined immunohistochemically 370 tumour‐free lymph nodes from 41 patients with a head and neck squamous cell carcinoma (HNSCC) to clarify whether the tumour‐associated epitopes CD44v6 and E48 are suitable for adjuvant postoperative immunotherapy. All the positively immunostained cells found were single cells. CD44v6(+) cells were found in 55% of the lymph nodes, with their numbers increasing in pN>0‐patients (62%). Only pN>0‐patients had abundant to massive CD44v6(+) cells. A comparison with mononuclear cells in lymphatic tissue from control patients suggested a similarity with activated T‐cells. In the 41 cancer patients there were significantly fewer lymph nodes with E48(+) cells (11%), but the number of E48(+) cells increased in pN>1‐patients (29%) with predominantly abundant E48(+) cells. We conclude from the comparison with the epithelial marker EMA that the E48(+) single cells are epithelial in origin. Only a specific E48 peptide sequence appears suitable for adjuvant immunotherapy in patients with head‐neck tumours.