Laser microdissection--a novel approach for accessing the molecular basis of cancer.

Background and aim: It has been known for quite a lot of time that tumours are cellular aggregates of different cells, mainly malignant cells but also immune cells – of which the most well-known are the tumour infiltrating lymphocytes (TIL) and the tumour associated macrophages (TAM). By observing hematoxylin – eosin stained or immunohistochemical stained slides belonging to different areas of the tumour it is clear that there are clusters of malignant cells within the tumour itself that seem to behave differently from the rest of the tumour. Another fact is that different areas of the tumour contain different inflammatory cells which may promote carcinogenesis or may help to confine it. Whereas different immune cells can be recognised by using immunohistochemistry, a satisfactory characterization of the molecular characteristics of the malignant clusters of the tumour cannot be made without further use of different molecular techniques such as different PCR techniques or microarray methods. Laser microdissection thus comes as a valuable aid in choosing exactly which cells will be analyzed further on. Principle of the method: Laser microdissection is based on using the energy of a focused laser beam to cut through the thickness of the tissue that is placed on a microscope slide in order to obtain cell samples previously selected by the pathologist through special software. Conclusions: To be able to cut the cells that you want and analyze them further without having them contaminated with other cells means that you can get more insight into the progression of the mutations that occur in these malignant cells, mutations that cause them to become more aggressive or multidrug-resistant. This could in time lead to the discovery of new molecular targets for cancer therapy.