Absence of lipopolysccharide (LPS) expression in breast cancer cells.

The relationship between bacterial activity and tumorigenesis has gained attention in recent years, complementing the well-established association between viruses and cancer. A recent study employed immunodetection of lipopolysaccharide (LPS) to demonstrate the presence of intracellular bacteria within cancer cells across various cancer types, including breast cancer. The authors proposed that these bacteria might play a role in tumor development. We sought to replicate these findings using the same experimental methods on an independent cohort of breast cancer cases. Our analysis of 129 samples revealed no evidence of LPS expression within cancer cells. Instead, LPS immunoreactivity was observed in ducts or immune cells, specifically macrophages, as expected. These discrepancies in LPS immunodetection warrant caution in interpreting the original findings, and further research is needed to clarify the potential role of intracellular bacteria in cancer development.