To facilitate the immunological reaction of antibodies with antigens in fixed tissues, it is necessary to unmask or retrieve the antigens through pretreatment of the specimens. However, adjustment of heat-induced antigen retrieval is always required for different tissues and antigens. Using a low-power antigen retrieval technique, with appropriate dilution of antibodies, we successfully immunostained key antigens in the pancreas such as insulin, PDX-1, glucagon, cytokeratin, and CD31, which have presented a particular challenge for investigators in the past, because of the rapid autodigestion and high nonspecific antibody binding in the tissue. Satisfactory results were obtained when immunohistochemistry and fluorescence in situ hybridization analysis were combined in the same slides.