Medical Sciences. In the article “A multidrug resistance transporter from human MCF-7 breast cancer cells” by L. Austin Doyle, Weidong Yang, Lynne V. Abruzzo, Tammy Krogmann, Yongming Gao, Arun K. Rishi, and Douglas D. Ross, which appeared in number 26, December 22, 1998, of Proc. Natl. Acad. Sci. USA (95, 15665–15670), the following corrections should be noted. In the abstract and text, later analyses reveals that BCRP is a 655 amino acid peptide, not 663 amino acids as stated in the article. The first 8 amino acids displayed in Fig. 2A on page 15667 should be removed, making the initial sequence of the peptide MSSSNVEVFI. . . . .

On page 15665 in the data deposition footnote, the GenBank database accession number for BCRP is incorrect. The correct accession number is AF098951.

On page 15670 in the “Note Added in Proof,” the accession number for the human EST clone that was homologous to BCRP is incorrect. The correct number is HUEST157481.