Is telomerase reactivation associated with the down-regulation of TGF beta receptor-II expression in human breast cancer?
BACKGROUND: Telomerase is a ribonucleoprotein that synthesizes telomeres and plays an important role in chromosomal stability and cellular immortalisation. Telomerase activity is detectable in most human cancers but not in normal somatic cells. TGF beta (transforming growth factor beta) is a member of a family of cytokines that are essential for cell survival and seems to be down-regulated in human cancer. Recent in vitro work using human breast cancer cell lines has suggested that TGF beta down-regulates the expression of hTERT (human telomerase reverse transcriptase) : the catalytic subunit of telomerase. We have therefore hypothesised that telomerase reactivation is associated with reduced immunohisto-chemical expression of TGF beta type II receptor (RII) in human breast cancer. METHODS: TGF beta RII immunohistochemical expression was determined in 24 infiltrating breast carcinomas with known telomerase activity (17 telomerase-positive and 7 telomerase-negative). Immunohistochemical expression of TGF beta RII was determined by a breast pathologist who was blinded to telomerase data. RESULTS: TGF beta RII was detected in all lesions. The percentage of stained cells ranged from 1-100%. The difference in TGF beta RII expression between telomerase positive and negative tumours was not statistically significant (p = 1.0). CONCLUSION: The results of this pilot study suggest that there is no significant association between telomerase reactivation and TGF-beta RII down-regulation in human breast cancer.
Elkak
Abd E
AE
St George's Hospital and Medical School, London, UK. kefahmokbel@hotmail.com
Newbold
Robert F
RF
Thomas
Valene
V
Mokbel
Kefah
K