Nature 431, 211–217 (2004).

In the Methods section of this Letter, the published primer sequences used to amplify the E-cadherin and erbB2 promoters for bisulphite sequencing were incorrect. We used two primer sets, one for unconverted DNAs and the other for converted DNAs. Primers for unconverted DNAs were: for the E-cadherin promoter, the forward primer was 5′-TCTAGAAAAATTTTTTAAAAA-3′ and the reverse primer was 5′-CAGCGCCGAGAGGCTGCGGCT-3′; for the erbB2 promoter, the forward primer was 5′-CCTGGAAGCCACAAGGTAAAC-3′ and reverse primer was 5′-TTTCTCCGGTCCCAATGGAGG-3′. Primers for converted DNAs were: for the E-cadherin promoter, the forward primer was 5′-TTTAGAAAAATTTTTTAAAAA-3′ and the reverse primer was 5′-CAACACCAAAAAACTACAACT-3′; for the erbB2 promoter, the forward primer was 5′-TTTGGAAGTTATAAGGTAAAT-3′ and the reverse primer was 5′-TTTCTCCAATCCCAATAAAAA-3′.