["New cytology" and diagnosis of malignant tumors]

Cytology is an old method of diagnosis: it is the microscopical observation of cells in the aim of their identification, of the recognition of morphological abnormalities to obtain diagnosis or prognosis informations. During the last 20 years, new technics have been developed: 1) Immunocytochemistry permits the identification of the tissue or the organ of which a tumoral cell population is born, the determination of its stage of differentiation, its kinetic and the diagnosis of bone marrow or lymph node metastasis. 2) With in situ molecular biology, it becomes possible to detect, at the cell level, virus, oncogenes or chromosomic abnormalities. 3) Flow and image cytometry are easy means for DNA content determination and for an objective and reproducible cell definition. None of these methods are able, at this time, to replace the cytological analysis, but they are useful, sometimes necessary, for the diagnosis and the prognosis evaluation of malignancy.