Applied molecular profiling: evidence-based decision-making for anticancer therapy

Applied molecular profiling is a method for helping clinicians select the most appropriate therapy for a patient with cancer by determining the level of gene and/or protein expression within the cancer and comparing that expression pattern with the expression profiles of cancers with known outcomes. This approach facilitates the development and selection of tumor-specific therapies based on the identification of biomarkers within a tumor. Molecular characterization techniques such as immunohistochemistry, microarray analysis, and fluorescence in situ hybridization have facilitated identification and validation of a number of important solid tumor biomarkers, including HER2/neu, EGFR, EML4/ALK, and KIT, and can also be used to identify biomarkers (eg, BCR-ABL, CD20, CD30) in various hematologic malignancies. It is of note that molecular profiling can be used to identify targets in tumors for which a therapeutic agent may already be available, thus avoiding the administration of an unproven investigational agent. As the field of molecular profiling continues to evolve and next-generation techniques such as exome sequencing – sequencing 1% of the genome – and whole gene sequencing gain currency, biomarker identification and analysis will become less expensive and more efficient, and possibly allow for a pathway-oriented approach to treatment selection. Wider acceptance and use of molecular profiling should therefore help practicing physicians and oncology researchers keep pace with advances in the understanding of oncogenic expression in various malignancies and encourage the use of molecular profiling in earlier stages of cancer rather than as an option of last resort.