Several histological techniques are employed to study drug resistance: - Light Microscopy: Allows for the observation of cellular and tissue architecture. - Immunohistochemistry: Utilizes antibodies to detect specific proteins, providing insights into the expression of resistance markers. - Electron Microscopy: Offers high-resolution images to observe ultrastructural details of cells. - In Situ Hybridization: Detects specific nucleic acid sequences to understand gene expression related to resistance.