Fusion genes in epithelial neoplasia

Recurrent chromosomal rearrangements with the formation of fusion genes have been traditionally associated with haematological and mesenchymal neoplasms. This view has cultivated the erroneous impression that the oncogenic mechanisms present in these tumours are fundamentally different from those found in epithelial neoplasms. In spite of the fact that, as a group, most epithelial tumours apparently show a higher degree of chromosomal instability, a careful and critical analysis of relatively older findings and several more recent discoveries has shown that some common mechanistic denominators occur in all forms of neoplasms independent of their line of differentiation. The aim of this review is to briefly review and discuss the occurrence, mechanisms and biological relevance of chromosomal rearrangements and fusion genes in epithelial neoplasia, with a special emphasis in thyroid, head and neck, kidney, breast, prostate and lung neoplasms.