The study looked at the KiSS1 gene (which makes the peptide kisspeptin) in breast cancer tissue and found that higher levels are seen in tumors compared to normal tissue, but lower levels are linked to metastasis and worse survival.

Breast cancer is the commonest female cancer worldwide and its propensity to metastasize negatively impacts on therapeutic outcome. Several clinicopathological parameters with prognostic/predictive significance have been associated with metastatic suppressor expression levels. The role of metastatic suppressor gene (MSG) KiSS1 in breast cancer remains unclear. Our goal was to investigate the possible clinical significance of KiSS1 breast cancer. The study was conducted on 87 histologically proven cases of breast cancer and background normal tiisue. Quantitative reverse transcriptase polymerase chain reaction (qRT PCR) and immunohistochemistry (IHC) were used to investigate KiSS1 at gene and protein levels, respectively, for correlation with several patient characteristics including age, family history, hormonal receptor status, stage, tumor size, nodal involvement and metastatic manifestation and finally with median overall survival (OS). Our study revealed (i) KiSS1 levels were generally elevated in breast cancer vs normal tissue (< 0.05). (ii) however, a statistically significant lower expression of KiSS1 was observed in metastatic vs non metastatic cases (P = 0.04). (iii) KiSS1 levels strongly correlated with T,N,M category, histological grade and advanced stage (<0.001) but not other studied parameters. (iv) Lastly, a significant correlation between expression of KiSS1 and median OS was found (P = 0.04). Conclusively, less elevated KiSS1 expression is a negative prognostic factor for OS, advancing tumor stage, axillary lymph node status, metastatic propensity and advancing grade of the breast cancer patient. Patients with negative KiSS1 expression may require a more intensive therapeutic strategy.