High levels at baseline of serum pyridinoline crosslinked carboxyterminal telopeptide of type I collagen are associated with worse prognosis for breast cancer patients.

It is speculated that adjuvant use of bisphosphonate reduces recurrence in breast cancer patients through suppression of bone resorption. To determine the prognostic impact of bone resorption markers, we investigated serum levels of the pyridinoline crosslinked carboxyterminal telopeptide of type I collagen (1CTP) and N-terminal crosslinking telopeptides of type I collagen (NTX). 1CTP and NTX were measured at baseline (before operation or neoadjuvant therapies) and afterward in 469 patients operated on breast cancer. The optimal cutoff value of 1CTP for relapse-free survival (RFS) was set at 3.6 ng/ml with an area under the receiver operating characteristics curve of 0.641 [95% confidence interval (CI) = 0.560-0.721; p = 0.0011]. However, we were unable to determine a significant cutoff value for NTX. RFS was significantly worse for 1CTP-high patients with than for those with low levels of 1CTP (p = 0.0002). Multivariate analysis with tumor size, lymph node metastasis, and nuclear grade showed that 1CTP was a significant independent prognostic factor (hazard ratio = 2.04, 95% CI = 1.13-3.68; p = 0.018). Worse prognosis for the subset with high 1CTP levels applied only to postmenopausal patients (p = 0.0002). RFS of 130 patients whose 1CTP changed from low at baseline to high at 6 months postoperatively showed RFS almost as poor as that for patients with high 1CTP throughout. These findings suggest that 1CTP may be useful not only for identifying patients with unfavorable prognosis, but also for selecting patients who may benefit from administration of bone-modifying agents in an adjuvant setting.

High Ki-67 Expression and Low Progesterone Receptor Expression Could Independently Lead to a Worse Prognosis for Postmenopausal Patients With Estrogen Receptor-Positive and HER2-Negative Breast Cancer.

UNLABELLED: We examined the prognostic significance of progesterone receptor (PgR) expression in immunohistochemical-based luminal subtypes defined by Ki-67 expression, taking menopausal status into consideration. The study included 327 surgically removed estrogen receptor-positive and human epidermal growth factor receptor 2-negative breast cancers. High Ki-67 expression (> 15%) and low PgR expression (£ 20%) were significant independent factors resulting in worse distant relapse-free survival. This association was observed in postmenopausalwomen but not in premenopausal women. BACKGROUND: Accurate classification of luminal A and luminal B characteristics of estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is considered clinically important for determining effective adjuvant treatment. Although Ki-67 expression has been identified as an essential constituent for this classification, the role of progesterone receptor (PgR) expression has yet to be fully elucidated. Because PgR expression is influenced by the estrogen milieu, we examined the prognostic significance of PgR expression in immunohistochemical (IHC)-based luminal subtypes defined by Ki-67 expression, taking menopausal status into consideration. MATERIALS AND METHODS: We examined 327 surgically removed ER(+) and HER2(-) breast cancer specimens. ER, PgR, and Ki67 expression was determined IHC for semiquantitative measurement. We used 1%, 20%, and 15% as the cutoff value for ER, PgR, and Ki-67, respectively. RESULTS: Breast cancer with low PgR (≤ 20%) expression was significantly associated with postmenopausal status, a large tumor size, and low ER expression. The low PgR expression subset had significantly worse distant relapse-free survival (DRFS) than the high PgR expression subset (P = .0067). This association was observed consistently in postmenopausal women but not in the premenopausal women. Multivariate analysis demonstrated that high Ki-67 expression (hazard ratio [HR], 3.80; 95% confidence interval [CI], 1.57-10.58; P = .003) and low PgR expression (HR, 2.54; 95% CI, 1.08-6.40; P = .038) were significant independent factors affecting DRFS. CONCLUSION: Low PgR expression was independently associated with a poorer prognosis for ER(+) and HER2(-) breast cancer. Determination of PgR expression combined with that of Ki-67 could thus improve the accuracy of IHC-based classification of luminal A and luminal B breast cancer, especially for postmenopausal women.

Association of body mass index with risk of luminal A but not luminal B estrogen receptor-positive and HER2-negative breast cancer for postmenopausal Japanese women.

BACKGROUND: The impact of body mass index (BMI) on the risk of postmenopausal estrogen receptor (ER)-positive breast cancers has been well documented. However, the mechanism for the impact of BMI on the etiology of luminal A and luminal B subtypes has not yet been identified. METHODS: We analyzed associations between BMI and breast cancers stratified by immunohistochemically defined intrinsic subtypes, and 1,297 Japanese women (615 breast cancer patients and 682 healthy women from a breast cancer screening program) were enrolled in a case-control study. ER-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancers were classified into luminal A and B subtypes according to Ki67 expression levels. RESULTS: Higher BMI was significantly positively associated with postmenopausal breast cancer risk for one-unit increase in BMI (adjusted odds ratio (aOR) 1.09, 95 % confidence interval (CI) 1.04-1.15; P = 0.0008). Analyses of postmenopausal women revealed that BMI was consistently and exclusively associated with luminal A incidence (aOR 1.18, 95 % CI 1.10-1.26; P < 0.0001). When BMI was divided into three categories corresponding to those of controls, among postmenopausal women, the observed positive association was confined to luminal A (high vs low, aOR 2.98, 95 % CI 1.53-5.80; P < 0.005), but not luminal B (aOR 0.95, 95 % CI 0.47-1.91) subtypes. CONCLUSIONS: We observed that BMI was significantly positively associated with increased risk of postmenopausal breast cancer for Japanese women with luminal A, but not with luminal B tumor subtype.

Biological characteristics of luminal subtypes in pre- and postmenopausal estrogen receptor-positive and HER2-negative breast cancers.

BACKGROUND: Estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancers can be divided into luminal A and luminal B subtypes based on Ki67 expression levels. However, the biological differences in ER and progesterone receptor (PR) expression levels between these luminal subtypes are not clear. METHODS: We examined immunohistochemical expression levels of ER, PR, and Ki67 in 180 ER-positive/HER2-negative breast cancers while taking menopausal status into account. Breast cancers were divided according to ER and PR levels (H: >50%, L: ≤ 50%), and luminal A and B were classified by the Ki67 labeling index (A: Ki67 <14%, B: Ki67 ≥ 14%). RESULTS: When breast cancers were classified based on ER and PR levels, the distribution of pre- and postmenopausals was significantly different for luminal A (P < 0.0001), but not for luminal B cancers. As for luminal A, ER-H/PR-L cancers were rare among premenopausals (8%), but frequent among postmenopausals (54%). Correlation between ER and PR levels among luminal A cancers was strong in premenopausals but weak in postmenopausals. Since crosstalk with growth factor signaling is unlikely in luminal A, we speculate that intratumoral estrogen insufficiency contributed to the characteristics of postmenopausal ER-H/PR-L cancers. CONCLUSION: We speculate that the biological characteristics of luminal A cancers are influenced by the estrogen environment, but its influence on luminal B cancers may be limited. We believe these considerations constitute useful information for a better understanding of the biology of ER-positive-HER2-negetive breast cancers.