Notably, a gradual decrease in B7-H4 expression levels was found in breast cancer patients with stage II (n = 609) or stage III (n = 243) as compared to patients with stage I (n = 273) (Fig. 6A), and the similar trend was also observed in cervical cancer and ovarian cancer according to the TCGA database (Additional file 6: Fig. S6A and B). This evidence concerns the gene VTCN1 and breast cancer.