Lectin Histochemistry for Metastasizing and Non-metastasizing Cancer Cells.

Changes in glycosylation of the cancer cell glycocalyx are a hallmark of metastasizing cancers and critically contribute to distant metastasis. In this chapter we concentrate on two lectins capable of specifically binding tumor-associated glycans in cryostat or formalin-fixed, paraffin-embedded tissue sections derived from primary clinical material, genetically engineered mouse models with endogenous cancer formation or xenograft mouse models. The snail lectin of Helix pomatia (HPA) binds N-acetylgalactosamine (GalNAc) that is expressed among others as Tn antigen (O-linked GalNAc) in primary tumors and metastases in several human adenocarcinomas. Another lectin, Phaseolus vulgaris leucoagglutinin (PHA-L) binds to complex β1-6 branched N-linked oligosaccharides associated with increased metastatic potential in breast, colon, and prostate cancer. Using these two lectins both O- and N-linked alterations in the glycocalyx of cancer cells can be monitored. As they are commercially available in a biotinylated or fluorescence-labeled form they can be readily used in cancer metastasis studies.