High ESR1 expression is not associated with IDO1 promoter methylation and reduced IDO1 expression in cervical and endometrial carcinoma. (A) IDO1 mRNA expression is higher in ESR1 high (n = 152, higher than the median ESR1 expression) than ESR1 low (n = 153, equal or lower than the median ESR1 expression) cervical cancers (TCGA, cervical squamous cell carcinoma and endocervical adenocarcinoma; Student's t-test, **p < 0.01). (B) The DNA methylation at cg10262052 inversely correlates with IDO1 mRNA expression derived from TCGA (n = 305, Spearman's rank correlation). (C) The DNA methylation level of cg10262052 does not differ between ESR1 low (n = 153) compared with ESR1 high (n = 152) cervical cancers (TCGA, cervical squamous cell carcinoma and endocervical adenocarcinoma, Mann–Whitney U test). (D) IDO1 mRNA expression does not differ between ESR1 low (n = 87, equal and lower than the median ESR1 expression) compared with ESR1 high (n = 86, higher than the median ESR1 expression) human endometrial carcinoma tissues derived from TCGA uterine corpus endometrial carcinoma RNASeq data; Student's t-test. (E) The DNA methylation at cg10262052 does not correlate with IDO1 mRNA expression derived from TCGA uterine corpus endometrial carcinoma (n = 173, Spearman's rank correlation). (F) The DNA methylation level of cg10262052 is lower in ESR1 high (n = 86) compared with ESR1 low (n = 87) endometrial carcinomas (TCGA, uterine corpus endometrial carcinoma, Mann–Whitney U test). Box plots represent the medians and the 75% and 25% percentiles. Whiskers extend to min and max values.