TKT and breast cancer: In addition to the marked inhibition of transplanted SHZ-88 breast cancer cells in the free SIEA flap, our study showed that CD/TK fusion gene expression was limited to the free SIEA flap tissue, and no viral sequence was detected in either the flap-bed interface or major internal organs following transfection of the SIEA flaps with LV-CDglyTK by intra-arterial perfusion.