- Topical colchicine selection of keratinocytes transduced with the multidrug resistance gene (MDR1) can sustain and enhance transgene expression in vivo. Pfutzner, W., Terunuma, A., Tock, C.L., Snead, E.K., Kolodka, T.M., Gottesman, M.M., Taichman, L., Vogel, J.C. Proc. Natl. Acad. Sci. U.S.A. (2002)