Lymphomas are a class of hematologic cancers that arise from a lymphocyte progenitor and develop in lymphatic tissues rather than in the bone marrow. Lymphomas often present as solid tumors composed of a variety of immune cells including lymphocytes, eosinophils, neutrophils, and histiocytes. Historically, lymphomas have been classified as Hodgkin's lymphoma or non-Hodgkin's lymphoma (NHL). Hodgkin's lymphoma, the rarer form of lymphoma, is characterized by the presence of large, abnormal B cells called Reed-Sternberg cells. Most NHL cases also arise from the B cell lineage but are more prone to dissemination than Hodgkin's lymphoma.
NHL dissemination is often correlated with a worse prognosis, and targeting the neoplastic cells is an area of active research. For example, the interaction of CD47 and SIRP alpha, which inhibits macrophage activity, has been implicated in promoting dissemination. Adhesion molecules, such as CD44, are important for both normal lymphocyte homing and NHL dissemination and may serve as useful biomarkers. The identification of additional cell surface markers, such as CD30, for both Hodgkin's lymphoma and NHL increases the potential to develop new tools to combat these cancers.