Microwave oven heating for antigen unmasking in routinely processed tissue sections

In 1962, following a thorough investigation of fixation protocols suitable for immunofluorescent studies, Sainte Marie concluded that 'antigen and antibody activity is inactivated by conventional methods', thereby dismissing the hope of immunohistochemical demonstration of antigens in routinely fixed and processed surgical biopsy specimens.' Thirty years on, this has proved to be far from the case. Improved techniques for the detection of antibody bound to target antigen, coupled with the improved quality and range of commercial reagents, have played significant roles. Pivotal to the application of many antibodies to routine diagnostic work was the discovery that predigestion of tissue sections by proteolytic enzymes could expose antigen binding sites concealed by the process of formalin fixation with its attendant alteration of protein tertiary structure.