OBJECTIVES: I. Evaluate the antitumor activity of bryostatin 1 in chemotherapy naive patients with metastatic or recurrent head and neck squamous cell carcinoma, not curable with surgery or radiation therapy. II. Evaluate the safety and toxicity of bryostatin 1 when administered in the prescribed schedule in this patient population. III. Assess cyclin dependent kinase 2 activity, protein kinase C activity, and apoptosis measurements in selected patients with tumors accessible for biopsy following bryostatin 1 therapy.