We are all aware of the recent rapid changes in cancer management mostly achieved with emerging new data regarding tumor biology. Currently, research in oncology is mainly focused on identifying the unique molecular characteristics of neoplasms and developing new targeted drugs to treat them. Although some tumors have specific genetic alterations that set off a cause-and-effect process after targeted treatment, those who work in the lung cancer field recognize that this is a more complex disease in which various genetic disorders carry its distinctive aggressiveness. At this time, the efforts of the scientific community are directed toward the identification of predictive markers to customize treatment based on specific genomic or protein expression profiles of individual tumors. This report provides a review on the breast cancer susceptibility gene 1, a promising gene determinant of response to different types of chemotherapy and its potential applications as a new molecular marker in lung cancer.