CD3 staining was used to evaluate the infiltration of T cells in formalin fixed paraffin-embedded (FFPE) breast cancer patient biopsies cleared with CLARITY (39), and surgical resections of patients with head and neck squamous cell carcinoma (HNSCC) were stained with antibodies against CD3 for T cells and CD66b for neutrophils before clearing with ECi (40) (Table 2). The gene discussed is CEACAM8; the disease is head and neck squamous cell carcinoma.