TPR and cancer: It is suggested that the differences for the expression levels of Hsp90 client proteins and enhancement of cellular uptake of Antp-TPR by R11-Hsp70 into MCF-10A compared with that of Antp-TPR by R11-Hsp70 toward cancer cells as described below might contribute to the less cytotoxic activity of Antp-TPR or combinational treatment of Antp-TPR with R11-Hsp70 toward MCF-10A than that of these peptides against cancer cell lines.