Amann JM et al. (2006) Selective profiling of proteins in lung cancer cells from fine-needle aspirates by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Clin Cancer Res 12: 5142–5150

There are several subtypes of lung cancer, which are difficult to differentiate between using current pathologic criteria. Currently, all subtypes of non-small-cell lung cancer receive the same treatment, although there is wide variability in clinical outcome. Thus, improved differentiation could have an important impact on clinical decision-making and patient outcomes.

Mass spectrometry has been considered particularly well suited as a diagnostic tool in cancer. Amann and co-workers investigated whether combining existing simple laboratory techniques with matrix-assisted laser desorption/ionization–time of flight (MALDI-TOF) mass spectrometry enabled selective profiling of proteins in lung cancer cells in mixed clinical samples, such as fine-needle aspirates.

Lung cancer cell lines were cytocentrifuged onto metal-coated glass slides and then fixed and stained for optimal morphologic identification. Fine-needle aspirates from murine allograft tumors and resected human tumors were also used to test the reproducibility of the method. An erythrocyte lysis protocol was added to reduce the hemoglobin content in the aspirates before cytocentrifugation, because hemoglobin suppresses any other protein signatures in clinical samples.

This simple method resulted in reproducible, sensitive, and selective cancer-cell-specific protein profiling, suggesting that this approach has the potential to refine the diagnosis of cancer, determine the cancer type, and predict both prognosis and response to treatment in clinical practice.