ALK and gastric cancer: Research into predictive biomarkers has improved, allowing the appropriate selection of patients for some types of treatment, evaluation of Human Epidermal Growth Factor Receptor 2 (HER2) expression in breast and gastric cancer and Epidermal Growth Factor Receptor (EGFR) and Anaplastic Lymphoma Kinase (ALK) mutations in Non-Small Cell Lung Cancer (NSCLC) being examples that enable selection of treatments that have little or no effect in patients lacking these biomarkers.