Accumulating genetic and epigenetic modifications lead to alterations in gene expression, resulting in dysregulation of cellular homeostasis. The transcriptional machinery comprises many factors that cooperate to modulate gene expression. “Crosstalk” between DNA-bound transcription factors may have synergistic or antagonistic effects on the rate of transcription. The aberrant expression of several transcription regulators in the vast majority of pathological conditions including neurodegenerative diseases and various malignancies, as well as their involvement in many cancer-related processes such as cell growth regulation, angiogenesis, invasion, and metastasis, renders transcription factors very appealing as potential molecular biomarkers and as candidates for targeted therapy. In the present mini-review, we provide a brief overview of the transcriptional machinery and summarize current knowledge regarding the implication of key transcription factors such as AP-1, NF-κB, STATs, HOX proteins, and histone modifiers, in human diseases, with emphasis on cancer.