The use of fluorescence in situ hybridization (FISH) on paraffin-embedded tissue sections for the study of microchimerism

We describe here a simple and versatile method of fluorescence in situ hybr idization (FISH) on paraffin-embedded tissue sections with specific applica tion in the study of microchimerism, that is, the presence of intact foreig n cells within an individual. This is accomplished through the use of X and Y chromosome-specific probes to identify the presence of male nuclei withi n a tissue section from a female, and vice versa. This technique requires o nly minor modification if at first the hybridization does not yield fluores cent signals of high quality Analysis of a wide variety of tissue types is possible with this method, and multiple tissue types from one or more indiv iduals can be processed in the same hybridization reaction. This robust FIS H method has been used successfully in our laboratory to investigate fetal cell microchimerism in the following paraffin-embedded tissue types: skin, lung, thyroid, adrenal gland lymph node, heart, spleen, liver pancreas, kid ney and intestine.