Role of ancillary studies in fine-needle aspiration from selected tumors.

The routine use of ancillary studies is reshaping the practice of cytopathology. Currently, most cytopathologists recognize the importance of immunocytochemistry and molecular techniques as adjuncts to morphology to achieve a precise diagnosis. Cytopathologists also are expected to include specific prognostic and predictive information in their reports. The objective of this review was to address the use of immunocytochemistry and molecular techniques to refine the preoperative diagnosis and classification of lung cancer, thyroid cancer, kidney cancer, gastrointestinal cancer, and soft tissue tumors. Fine-needle aspiration also offers a suitable alternative to biopsy in a variety of clinical settings, in particular, when it may be useful to obtain material to study prognostic and predictive markers. This is particularly relevant to obtain material from metastatic sites. The study of KRAS in colon cancer, CKIT in gastrointestinal stromal tumors, and epidermal growth factor receptor mutational status in lung cancer also are addressed particularly in this report.