Molecular testing of non-small cell lung carcinoma biopsy and cytology specimens.

During the past decade, substantial progress has been made in the characterization of molecular abnormalities in non-small cell carcinoma (NSCLC) tumors that are being used as molecular targets and predictive biomarkers for selection of targeted therapy. These recent advances in NSCLC targeted therapy require the analysis of a panel of molecular abnormalities in tumor specimens, including gene mutations (e.g., EGFR, KRAS, BRAF, DDR2), gene amplifications (e.g., MET, FGFR1), and fusions (e.g., EML4-ALK) by applying different methods to tumor tissue (biopsy) and cell (cytology) samples. However, the biopsy and cytology samples available for molecular testing in advanced metastatic NSCLC tumors are likely to be small specimens, including core needle biopsies and/or fine needle aspiration, which may limit the molecular and genomic analysis with currently available methods and technologies. In this process, the role of the pathologist is becoming increasingly important to adequately integrate both routine histopathologic assessment and molecular testing into the clinical pathology for proper tumor diagnosis and subsequent selection of the most appropriate therapy.