Predictive value of cathepsin-D for cervical lymph node metastasis in head and neck squamous cell carcinoma

Background: Prognosis of head and neck squamous cell carcinoma (HNSCC) is strongly associated with cervical lymph node metastasis. Cathepsin-D is a lysosomal protease expressed in all cells. Its role in extracellular matrix degradation is postulated to promote tumor invasion and metastasis. Increased cathepsin-D has been demonstrated in cervical lymph node metastasis in HNSCC.

Methods: Formalin fixed tumor biopsy samples from 34 patients with HNSCC of the oral cavity, oropharynx, or hypopharynx were analyzed for the presence of cathepsin-D by immunohistochemistry (1:8000, Calbiochem, Cambridge, MA). Tumors were considered positive if >50% of cells showed strong cytoplasmic staining.

Results: All patients had T1 or T2 lesions ranging in size from 1-4 cm and 19 (56%) had cervical metastasis. Eight (24%) were well differentiated and 26 (76%) were moderately or poorly differentiated. Thirteen tumors (38%) had high cathepsin-D expression that was strongly associated with cervical lymph node metastasis (p = 0.008). When adjusted for tumor stage and grade, cathepsin-D positivity was nearly twice as likely to be associated with node metastasis (p = 0.011).

Conclusions: We demonstrated cathepsin-D expression in biopsies from a subset of patients with HNSCC and a strong association between this protease and cervical lymph node metastases. Cathepsin-D is a potential independent predictor of cervical lymph node metastasis in HNSCC and merits additional study.