Analysis of tumour-specific alterations in native specimens by PCR

Native tumours, in contrast to cell lines, are usually heterogeneous, consisting of tumour cells, stroma, infiltrating leukocytes, necrotic cells, and surrounding normal tissue. Therefore, when using non-linear amplification and detection methods such as the PCR, the verification of the DNA from the tumour cells is mandatory to avoid equivocal or false results. Here, current methods to isolate tumour cells from native tumours are reviewed. The methods are: i) a variety of microdissection techniques including microdissection of membrane-mounted native tissue (MOMeNT), ii) Selective ultraviolet radiation fractionation (SURF), iii) antibody-based tumour cell selection and flow cytometric cell or cell nucleus sorting, and iv) in situ PCR. Each of the methods has been used, and overall preference cannot be given to any of them. Accuracy, reproducibility, documentation, cost, and applicability in a routine setting are discussed, from which fields of preferencial use may emerge for the different methods.