CD19 and head and neck squamous cell carcinoma: Sections of 22 matched biopsy pairs obtained from HNSCC patients prior to and after 3–4 weeks of neoadjuvant cetuximab therapy were stained using the Vectra 3.0 platform for the tumor marker cytokeratin 7 (CK7), the T cell markers, CD3 and CD8, the monocyte/macrophage marker, CD14, and the B cell marker, CD19 (see Materials and Methods).