title: Telomerase activity in normal and neoplastic breast.
abstract: Telomerase activity is detected in the majority of human tumors and provides a mechanism to escape from proliferative limitations due to telomere loss. Similar to other studies, telomerase activity was detected with a modified telomeric repeat amplification protocol in the majority (76%) of 49 human breast cancer specimens, including most (75%) ductal carcinoma in situ specimens. There were no correlations between telomerase activity and tumor stage or estrogen/progesterone receptor status. In four of seven invasive tumors, telomerase expression seemed to be heterogeneous because not all microdissected regions were telomerase positive. Low levels of telomerase activity were also detected in a minority (17%) of breast specimens from patients without evidence of cancer. These findings suggest that telomerase activation can occur early in breast cancer progression and may be periodically down-regulated during subsequent progression.
authors.affiliation: Department of Pathology, University of Southern California School of Medicine, Los Angeles, California 90033, USA.
authors.forename: J l
authors.initials: Jl
authors.lastname: Tsao
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: J
authors.initials: J
authors.lastname: Lukas
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: A
authors.initials: A
authors.lastname: Shah
authors.forename: M
authors.initials: M
authors.lastname: Press
authors.forename: D
authors.initials: D
authors.lastname: Shibata
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D001940:Breast / Q000201:enzymology*; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D002278:Carcinoma in Situ / Q000201:enzymology / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000201:enzymology / Q000473:pathology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008597:Menstrual Cycle; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011247:Pregnancy; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012016:Reference Values; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D019098:Telomerase