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.