AIM:The structural and functional characteristics of cellsare dependent on the specific gene expression profile.Theability to study and compare gene expression at the cellularlevel will therefore provide valuable insights into cellphysiology and pathophysiology.METHODS:Individual cells were isolated from frozen colontissue sections using laser microdissection.DNA as well asRNA were extracted,and total RNA was reversely transcribedto complementary DNA (cDNA).Both DNA and cDNA wereanalyzed by nested polymerase chain reaction (PCR).Thequality of isolated DNA and RNA was satisfactory.RESULTS:Single cells were successfully microdissectedusing an ultraviolet laser micromanipulator.Nested PCRamplification products of DNA and cDNA of single cells couldclearly be visualized by agarose gel electrophoresis.CONCLUSION:The combined use of laser microdissectionand nested-PeR provides an opportunity to analyze geneexpression in single cells.This method allows the analysisand identification of specific genes which are involved inphysiological and pathophysiological processes in a complexof variable cell phenotypes. AIM: The structural and functional characteristics of cellsare dependent on the specific gene expression profile. Theability to study and compare gene expression at the cellularlevel will therefore provide valuable insights into cell physiology and pathophysiology. METHODS: Individual cells were isolated from frozen colontissue sections using laser microdissection . DNA as well as RNA were extracted, and total RNA was reversely transcribed complementary DNA (cDNA). The DNA and RNA were was analyzed by nested polymerase chain reaction (PCR). The quality of isolated DNA and RNA was satisfactory. RESULTS: Single cells were successfully microdissected using an ultraviolet laser micromanipulator. Detection of DNA and cDNA of single cells couldclearly be visualized by agarose gel electrophoresis. CONCLUSION: The combined use of laser microdissection and nested-PeR provides an opportunity to analyze geneexpression in single cells. This method allows the analysis and identification of specifi c genes which are involved in physiological and pathophysiological processes in a complex of variable cell phenotypes.