Assessment of interleukin-6 and cathepsin-B gene expression in breast cancer women

Breast cancer (BC) is the most prevalent cancer and the leading cause of cancer-related deaths in women globally. Cysteine protease cathepsin-B has been implicated in various human malignancies and is involved in malignancy progression and metastasis. This study aimed to evaluate the circulating levels of cathepsin-B, interleukin-6 (IL-6), and CA15-3, a cancer antigen, as biomarkers for tumors in women with both localized and metastatic BC. The study employed a case-control design, enrolling 108 participants categorized into three groups: healthy individuals, those with localized BC, and those with metastatic BC. The relative mRNA expression of cathepsin-B in blood samples was assessed using qRT-PCR. Additionally, serum levels of IL-6 and CA15-3 were quantified using ELISA. The relative mRNA expression of cathepsin-B, IL-6 levels, and CA15-3 levels were significantly higher in metastatic BC cases than in localized BC cases and the control group (p-value < 0.001). A statistically significant positive correlation was also found between cathepsin-B and both IL-6 and CA15-3 (r = 0.905, r = 0.667, and p < 0.001), respectively. The findings indicate a strong correlation between the interaction of the proteolytic enzyme cathepsin-B and IL-6 with the unfavorable prognosis of BC. This relationship may serve as a potential indicator and a promising target for therapy in BC treatment.