FFPE stands for Formalin-Fixed Paraffin-Embedded. This is a process used in pathology and research to preserve tissue samples. First, the tissue is treated with formaldehyde to preserve its structure and prevent degradation. Then, it is embedded in paraffin wax to provide a stable block that can be easily sliced into thin sections for microscopic analysis. FFPE is commonly used for long-term storage at room temperature of biological samples for histological studies and molecular analysis.