Laser capture microdissection (LCM) Characterization of the complex molecular interactions that take place during various cell functions is the goal of all molecular biologists. Most recently, several techiques have been developed to get a glimpse on these molecular expression profiles. Serial analysis of gene expression (SAGE) and DNA array technology are the initial attempts that are turning this goal into reality. Tissues are made of a complex admixture of cells. Therefore, application of such technologies to tissues requires methods for precise selection of cells or structures. In the November 6 issue of Science, a group headed by Lance Liotta, report on a technique that would allow precise retrieval of cells or structures from tissue sections. The technique consists of the following steps: 1. Mount the tissue section on slide. 2. Apply a transparent EVA thermoplastic film over the section. 3. Place the section on the microscope slide. 4. Position the structure or cell of interest in the center of the field of view. 5. Apply a carbon dioxide laser pulse, coaxial with the microscope optics, to the point of interest to activate the film. This will cause the film to become adhesive at the pulse field. As a result, the cells at the pulse field will selectively adhere to the film. 6. Remove the film. 7. The cells adherent to the film can be viewed under the microscope to assure that they are correctly procured. 8. The selected cells can be used for PCR, RT-PCR or any other application. When combined with other tools available for global characterization of gene expression, this method is likely to give us an indepth insight on the molecular expression profile of various cells. This method would alsoallow obtaining a specific genetic fingerprint that can be used in molecular diagnostics. Reference: Emmert-Buck MR, Bonner RF, Simth PD, Chuaqui RF, Zhuang Z, Goldstein SR, Weiss RA, Liotta LA: Laser capture microdissection. Science, 274, 996-1001, 1996