The Role of Prostaglandin D2 Reseptor DP and PPARγ in Bone Metastasis of Breast Cancer

The prevalence of breast cancer is one the highest among all groups of cancers in women around the world, causing many bone metastases cases. Prostaglandin D2 (PGD2) DP and PPARã are known to have a substantial effect in inhibiting bone metastasis in breast cancer. This research aims to analyze the expression of PGD2 (DP) and PPARã in bone metastasis in breast cancer. An observational analytic research with a cross sectional retrospective approach was done on 44 FFPE tissues from breast cancer in the Anatomical Pathology Laboratory at Dr. Soetomo General Hospital, Surabaya. The samples were divided into 2 groups based on whether bone metastasis is present or not, then the samples were immunostained using PGD2 (DP) and PPARã antibodies. The difference of PGD2 (DP) and PPARã expression were analyzed using Mann-Whitney and the correlation of PGD2 (DP) and PPARã were analyzed using the Spearman test. Results in this study showed a significantly lower expression of PGD2 (DP) in breast cancer where bone metastasis is present in comparison to breast cancer where bone metastasis is not present (p=0.002). Significant expression of PPARã was also revealed to be lower in breast cancer cases with bone metastasis in comparison with breast cancer cases where bone metastasis is not present (p=0.001). Statistical analysis demonstrated a significant relationship between the PGD2 expression (DP) and PPARã in bone metastasis breast cancer (rs = 0.780, p = 0.000). In conclusion, PGD2 (DP) and PPARã expression were revealed to be significantly lower in breast cancer cases with bone metastasis in comparison to breast cancer cases where bone metastasis is not present. The significant correlation between PGD2 (DP) and PPARã expression proves that these two proteins play a substantial part in bone metastasis found in breast cancer cases.