Tumor Microenvironment

While genetic changes are critical for the malignant transformation of epithelial cells, the microenvironment in which the cells reside also governs carcinogenesis. Most tumors arise within a cellular microenvironment characterized by suppressed host immunity, dysregulated inflammation, and increased production of cellular growth and survival factors that induce angiogenesis and inhibit apoptosis. The studies highlighted in this chapter indicate that the lung tumor and its microenvironment interact, together informing the process of carcinogenesis. Understanding the molecular mechanisms driving the contributions of the tumor microenvironment to lung carcinogenesis may afford us the opportunity to develop new drugs that target these reversible nonmutational events in the prevention and treatment of lung cancer. Findings from recent microenvironment-related clinical studies have implications for understanding the immunopathobiology of lung cancer, for targeting surgery and adjuvant therapy, and for designing future trials of adjuvant therapy. If the field is to progress and promising leads in the laboratory are to translate into anticancer therapeutics, future trials targeting the tumor microenvironment must incorporate improved patient risk assessment and selection, in addition to the continued evaluation of combination therapies using the optimal biological dose of each compound being tested. Appropriately targeting the tumor microenvironment in a highly selected patient population is a newly emerging strategy that holds unique potential for advancing the current state of lung cancer prevention and treatment.