**7. Conclusions**

Brain metastasis of NSCLC is most life-threatening for patients and the treatment is a major challenge. Traditional therapies do not eradicate cerebral cancer cells and recurrent disease is common. A significant obstacle in treating patients with brain metastases is the BBB, which prevents chemotherapeutic agents from entering the brain. Due to this obstacle and the failure of conventional therapies, novel therapeutic approaches are being explored. Despite recent advances in lung cancer treatment, a better understanding of the molecular mechanisms and pathways implicated in lung cancer is essential to identify appropriate targets to prevent brain metastasis. It is undeniable that many factors in the tumor microenvironment contribute to the outgrowth of tumor cells, not only at the primary site but also at the sites of seeding in distant organs. The formation of brain metastases is largely the result of tumormicroenvironment interactions. The brain micro-environment not only contributes to colonization by tumor cells but also affects the results of therapeutic interventions. Obviously, detailing the entire spectrum of genomic alterations and molecular mechanisms involved in lung cancer brain metastasis is important to develop effective treatments. Specifically scrutinizing the mechanisms by which cancer cells cross the BBB is important for establishing preventive brain metastases strategies.
