A high-zoom-ratio zoom lens having superb optical performance despite compactness and a high zoom ratio. Its form is the elongated elastic sleeve with an elliptical cross-section before application. The PDLC material offers all of the features of holographic photopolymers with the added advantage that the hologram can be switched on and off with the application of an electric field. Also provided are methods of inhibiting or destroying mammalian cancer cells using the cytotoxins of the invention and pharmaceutical compositions for treating human cancer.