Characterization of the MCT-1 pseudogene: Identification and implication of its location in a highly amplified region of chromosome 20

The MCT-1 oncogene was initially identified as an amplified gene on chromosome Xq22–24 in a T-cell lymphoma. MCT-1 is over-expressed in a subset of diffuse large B-cell lymphoma (DLBCL), a common form of Non-Hodgkin's Lymphoma (NHL). We have identified a pseudogene for MCT-1 (ΨMCT-1) that is located on chromosome 20q11.2, a region within an amplicon containing several important genes frequently amplified in certain breast and ovarian cancers. Genomic analysis revealed that ΨMCT-1 is a processed pseudogene. Interestingly, both MCT-1 and its pseudogene are located on regions of the genome that are frequently amplified in several different human malignancies. MCT-1 is the oldest known oncogene and its insertion as a pseudogene occurred at a later time point in evolution. Existence of ΨMCT-1 should be considered when analyzing genomic amplification and or expression of MCT-1. Analysis of MCT-1 and ΨMCT-1 might provide clues to cancer genes and their evolution across species.