CD33 and thymoma: To address if IGK is expressed in mature myeloid cells, we sorted CD33+CD19−CD138− neutrophils (Figure 3A, upper panel) and monocytes (Figure 3A, lower panel) from 12 patients with non-hematopoietic neoplasms (including 4 cases of colorectal adenocarcinoma, 2 cases of stomach adenocarcinoma, 2 cases of squamous cell carcinoma, and 1 case each of pancreatic adenocarcinoma, high-grade sarcoma, glioblastoma and thymoma), as well as 8 healthy individuals.