In the version of this article initially published, the sample size (n = 794) was incorrect in Fig. 2f and Extended Data Fig. 4a,e; the correct sample size is ‘n = 397’. The sample size (n = 826) was also incorrect in Fig. 2h and Extended Data Fig. 4q,u; the correct sample size is ‘n = 413’. Also, the values in Supplementary Table 2, row ‘TCGA-HNSC’, column ‘Quality OK and tumor on slide’ (424, 424) were incorrect;the correct values are ‘457, 439’. The errors have been corrected in the HTML and PDF versions of the article.