HOXB9 and breast carcinoma: [16] In this study, IHC staining of 139 breast cancer patients' tissues was performed to assess the connection between E2F1 and HOXB9 in clinical samples, and E2F1 positivity and negativity was found to associate significantly (p<0.001) with HOXB9 staining, which was expected from our in vitro study.