The present invention is directed to compounds, agents, pharmaceutically active agents, medicaments, therapeutics, actives, drugs and the like which specifically target a portion of the HAS molecule which is accessible to the extracellular environment in a first form of a cell but which is not accessible to the extracellular environment in another form of or in a transformed cell form the same or related cell. In particular, the present invention provides compounds which target a portion of HAS which is accessible to the extracellular environment in malignant or inflammatory or proliferative cells but which portion is not accessible to the external environment in "normal" cells. A "normal" cell in this instance is a non-malignant, inflammatory or proliferative cell.