Importantly, CAIX and other targets of therapeutic antibodies are plasma membrane resident proteins more or less modified by glycosylation, which is known to have a major impact on the sorting of cell-surface proteins [9], e.g. it was recently reported that tumor resistance to the EGFR-targeting antibody cetuximab correlates with reduced EGFR stability due to deficient glycosylation [10]. The gene discussed is CA9; the disease is neoplasm.