Telomerase Activity and Prognosis in Primary Breast Cancers

Abstract

Telomerase activity level was associated with the proliferative index of invasive breast cancers, but its measurement in samples from this group of nonmetastatic breast cancer patients did not predict survival.

Telomerase activity in ductal carcinoma in situ and invasive breast cancer

“…Nevertheless, almost a third of our DCIS samples were telomerase-negative, whereas all invasive cancer samples were telomerase-positive. Thus, telomerase activation may indeed be occurring in DCIS, since invasive breast cancer is usually telomerase positive even in early stages (Carey et al, 1998), and limited data on atypical hyperplasia (Poremba et al, 1998) suggest that earlier lesions are telomerase negative. While the source of low but detectable levels of telomerase in ®broadenomas (Hiyama et al, 1996;Poremba et al, 1998) will need to be investigated further, these lesions do not generally pose diagnostic di culties.…”

“…Telomerase activity has been proposed as a potentially useful tumor marker in breast cancer, since it has been detected in most invasive breast cancers, but not in benign breast lesions, with the possible exception of some ®broadenomas (Kim et al, 1994;Meeker and Co ey, 1997;Nelson, 1996;Shay and Bacchetti, 1997). In several studies of primary invasive breast cancers, approximately 75 ± 95% of tumors demonstrate telomerase activity, while 5 ± 25% are telomerase-negative (Bednarek et al, 1997;Carey et al, 1998;Hiyama et al, 1996;Landberg et al, 1997;Nawaz et al, 1997). Initial results suggested that smaller, lymph nodenegative tumors were more likely to be telomerasenegative than their larger, lymph node-positive counterparts (Hiyama et al, 1996;Kim et al, 1994), and it was postulated that telomerase activity is acquired during tumor progression to metastasis (Hiyama et al, 1996).…”

“…More recently, some studies have found correlations between telomerase activity and stage, traditional prognostic indicators, and clinical outcome in invasive breast cancer (Clark et al, 1997;Hoos et al, 1998). Other studies, however, failed to show a correlation between telomerase activity and prognostic factors or clinical outcome in breast cancer (Bednarek et al, 1997;Carey et al, 1998;Nawaz et al, 1997;Sugino et al, 1996;Tsao et al, 1997) and (Carey et al, in preparation, 1999).…”

“…Previous reports have detected telomerase activity in anywhere form 60 ± 100% of ductal carcinoma in situ (DCIS) of the breast (Bednarek et al, 1997;Poremba et al, 1998;Tsao et al, 1997;Yashima et al, 1998), but the studies have been limited by small sample sizes (n=5 ± 17). The large proportion of invasive breast cancers that are telomerase positive (Carey et al, 1998) also suggest that telomerase activation may occur in early stages of the disease. We have therefore focused our attention on ductal carcinoma in situ (DCIS), a preinvasive lesion of the breast, as a possible stage in carcinogenesis in which telomerase activation occurs.…”

DNA Flow Cytometry but Not Telomerase Activity as Predictor of Disease-Free Survival in pT1–2/N0/G2 Breast Cancer

“…Mokbel et al [22] , using a PCR-based assay, showed that telomerase activity in breast cancer is not associated with nodal status or disease outcome. Carey et al [23] , studying 203 invasive breast cancers by the TRAP method, found that telomerase activity was associated with the proliferative index but did not predict survival. Nawaz et al [24] reported no significant difference in telomerase expression between node-negative and nodepositive breast carcinoma, as well as with tumor size and hormonal status.…”