One of the main changes that occur as a consequence of cancer genetic and epigenetic alterations is represented by transcriptional deregulation. Further, these deregulated RNA species can serve as an essential pillar to oncogenesis. Because of this pillar role of several transcriptional deregulations, several research groups have aimed at targeting the affected pathway as a new therapeutic approach in cancer. Here, we discuss the most relevant transcriptional deregulations that can occur in cancer cells, as well as the biological mechanisms of oncogenic addiction. By providing a comprehensive view regarding these aspects, we tried to highlight relevant information about how genetic alterations can govern cancer progression and development.