Rapid Immunostaining of Frozen Sections

Rapid immunohistochemical study of frozen sections is necessary for intraoperative diagnosis in some cases. Rapid immunostaining is also helpful in confirming or excluding tumor clearance in resection margins or in detecting micrometastases in sentinel lymph nodes in breast cancer patients. Two methods to immunostain frozen sections are the enhanced polymer one-step staining (EPOS) system and the EnVision system both systems are detailed later. 

Staining method Conventional time (hr) Microwave time (min) 

In contrast to the EPOS system, a modification of the highly sensitive two-step immunohistochemical EnVision system allows the detection of a broad spectrum of antigens in frozen sections in less than 13 min (Kammerer et al., 2001). In this study 38 out of 45 antibodies tested showed specific staining. In fact, the modified EnVision procedure allows the use of any suitable primary antibody, preferably monoclonal antibodies. Like the EPOS system, EnVision employs a dextran polymer coupled to horseradish peroxidase molecules for detection. No attempt was made to block endogenous peroxidase, nor was any antigen retrieval pretreatment used. Because of the very short incubation durations, a humid chamber is not required to avoid evaporation of immunoreagents. 

A minor disadvantage of the modified EnVision system is that it requires primary antibody concentrations four- to tenfold higher than those used in the conventional immunohistochemical procedures. Another limitation of this modified method is that only two slides with two sections each can be processed at any one time. 

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MICROWAVE HEAT-ASSISTED RAPID IMMUNOSTAINING OF FROZEN SECTIONS... 

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