Haber's laboratory interests have focused on the area of cancer genetics, including the etiology of the pediatric kidney cancer Wilms tumor and genetic predisposition to breast cancer. Recently, his laboratory reported that lung cancers with activating mutations in the epidermal growth factor receptor (EGFR) define a subset of "nonsmokers' lung cancer" that are uniquely sensitive to new targeted therapies that target this receptor (tyrosine kinase inhibitors including erlotinib (Tarceva) and gefitinib (Iressa)). This observation has had important implications for the genotype-directed treatment of non-small cell lung cancer, and more broadly for strategies to identify critical genetic lesions in cancers that may serve as an "Achilles heel" and be suitable for molecular targeting. In a collaboration with MGH bioengineering professor Dr. Mehmet Toner, Dr. Haber’s group has recently established the application of a novel microfluidic technology for quantifying and purifying rare circulating tumor cells (CTCs) from the blood of patients with various epithelial cancers. This new application has potentially profound implications for early diagnosis of cancer and for noninvasive molecular profiling of cancers during the course of therapy.