Before revision:  However, tissue sections are stained with a mixture of antibodies , DNA and RNA markers, the detection of weak or broken edges due to fluorescent membrane staining artifacts between touching or overlapping cells is a long term studied problem, and is an active research topic in biomedical image analysis.
After revision:  However, tissue sections are stained with a mixture of antibodies , DNA and RNA biomarkers are introducing various complexities, including spurious edges due to fluorescent membrane staining artifacts between touching or overlapping cells is a long term studied problem, and is an active research topic in biomedical image analysis.