|
 |
|||||||||||||||||||
|
|||||||||||||||||||
|
|||||||||||||||||||
 |
 |
|
|
 -NB Is the Human Isoform of Rat Thymosin 15
a Vascular Biology Program, Department of Surgery, Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
Key Words: thymosin  15 • thymosin NB • prostate cancer
Address for correspondence: Bruce R. Zetter, Vascular Biology Program, Department of Surgery, Karp Family Research Laboratories, 11-125, Children's Hospital, 300 Longwood Ave, Boston, MA 02115. Voice: 617-919-2320; fax: 617-730-0268. bruce.zetter{at}childrens.harvard.edu
Thymosin
15 is a small actin-binding protein upregulated in highly metastatic rat prostate cancer cells, relative to low metastatic cells. We have previously established an important role for thymosin 15 as a diagnostic marker in human prostate cancer, with potential as a prognostic indicator. We here review the data supporting increased thymosin 15 expression in other cancer types, including breast, brain, and lung. Human NB thymosin is a -thymosin originally found in neuroblastoma. New data demonstrate that NB thymosin represents the human homolog of rat thymosin 15; thus we suggest classification as human thymosin 15. In addition to the previously described gene, thymosin 15a, we report the discovery of a new isoform of human thymosin 15, thymosin 15b, which is transcribed from an independent gene on human chromosome X. The gene structure of thymosin 15a and 15b is conserved and the isoforms show 87% identity across the nucleotide sequence. Across the coding sequence the nucleotide differences are silent, resulting in identical proteins. Other thymosin family members have recently been shown to exert potent clinical effects. The functional data available for thymosin 15, combined with the tumor expression pattern, suggest that thymosin 15 may play an important role in tumor development and progression in addition to its value as a biomarker in prostate cancer.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
