The study found that the proteins Kiss‑1 and its receptor GPR54 are present at higher levels in breast cancer tissue compared to non‑cancerous breast tissue, but these levels don’t predict how aggressive the tumor is.

Numerous studies have shown that the Kiss-1 gene countervails the metastatic aptitude of several cancer cell lines and solid-tumor neoplasias. However, there still remains ambiguity regarding its role in breast cancer and literature has arisen asserting that Kiss-1 expression may be linked to an aggressive phenotype and malignant progression. Herein, we investigated the protein expression of Kiss-1 and its receptor GPR54 in breast cancer tissues compared to non-cancerous mammary tissues. Paraffin-fixed cancer tissues from 43 women with resected breast adenocarcinomas and 11 specimens derived from women suffering from fibrocystic disease, serving as controls, were immunostained with Kiss-1 and GPR54 antibodies. Kiss-1 and GPR54 protein expression levels were significantly higher in breast cancer compared to fibrocystic tissues (p<0.05). No significant correlation was established between Kiss-1 or GRP54 expression and tumor grade, tumor size, lymph node positivity, histological type or ER status. Kiss-1 expression significantly and positively correlated with GPR54 expression in both breast cancer and fibrocystic disease specimens. Kiss-1/GPR54 expression was found to be significantly higher in breast cancer compared to non-malignant mammary tissues.