Objective  To explore the expression of bone morphogenetic protein 9 (BMP-9)and insulin-like growth factor-1(IGF-1) in different molecular subtypes of breast cancer and their correlations with clinical features.

  Methods  A total of 98 breast cancer patients were divided into Luminal A type group (n=23), Luminal B type group (n=26), HER-2 overexpression type group (n=24), Basal-like type group (n=25) according to different molecular subtypes of breast cancer. The expression levels of BMP-9 and IGF-1 of four groups were compared, and the relationships between the expression levels of BMP-9 as well as IGF-1 and clinical signs were analyzed.

  Results  In 98 cases of breast cancer, BMP-9 was negatively expressed in 36 cases and positively expressed in 62 cases. BMP-9 mRNA level and BMP-9 protein positive rate in the HER-2 overexpression type group and the Basal-like type group were significantly lower than those in the Luminal A type group and the Luminal B type group, and the Luminal B type group was significantly lower than that in the Luminal A type group (P < 0.05). In 98 cases of breast cancer, IGF-1 was negatively expressed in 36 cases and positively expressed in 62 cases. IGF-1 mRNA level and IGF-1 protein positive rate in the HER-2 overexpression type group and the Basal-like type group were significantly higher than those in the Luminal A and Luminal B type groups, and the Luminal B type group was significantly higher than that in the Luminal A type group (P < 0.05). The expression of BMP-9 was negatively correlated with tumor diameter, the number of lymph node metastasis and TNM staging; the expression of IGF-1 was positively correlated with tumor diameter, the number of lymph node metastasis and TNM staging.

  Conclusion  The expressions of BMP-9 and IGF-1 are related to the clinical molecular subtypes of breast cancer patients. In clinical practice, BMP-9 and IGF-1 can be included in the detection of breast cancer to predict the clinical treatment effect of patients.