[Cytopathology--current trends]

Modern imaging techniques help to detect minute tumours, even in remote locations of the body. This increases the demand to sample cellular material by minimal invasive procedures, such as fine needle aspiration (FNA). For optimal treatment, tumour cells should be characterized for prognostically relevant features. Primary and metastatic neoplasms, and individual disseminated cells of solid tumours are targets for FNA and exfoliative cytology. Recognition and typing of tumour cells is aided by immunochemistry and PCR based molecular studies. Especially immunostaining requires laboratory procedures adapted to cytology samples. Screening for precancerous lesions, highly successful in cervical cancer prevention, extends into areas such as bladder and lung cancer in selected patient groups. Cell image analysis, especially for DNA ploidy, and chromosomal FISH of interphase cells can have predictive value enhancing the information derived from the purely morphologic assessment. Prognostic tumour cell markers are studied using immunochemistry and PCR on cytological material. Cytology has to foster translational research and test the results from molecular cytogenetics, including comparative genomic hybridisation (CGH) and cDNA microarray techniques on dissociated solid tumour cells. Newly identified genetic abnormalities can be evaluated for their functional relevance and may correlate with distinct structural alterations of the tumour cells. Proper training, dedication to diagnostic cytologic work and molecular studies, and sufficient staffing will enable cytology to get the most for the patient out of limited cell material. This approach helps to distinguish genetically defined tumour subtypes by recognizing properties of the cell gestalt.