Hormonal manipulations and breast cancer

Short-term outcome of primary operated early breast cancer by hormone and HER-2 receptors

INTRODUCTION

Prognostic subgroup classification of operable breast cancers using cDNA clustering of breast cancer-related genes resembles the classification based on the combined immunohistochemical (IHC) expression of the hormone and HER-2 receptors. We here report the short-term disease-free interval (DFI) of operable breast cancers by their joint hormone receptor/HER-2 phenotype.

PATIENTS AND METHODS

Short-term follow-up (FU) of a prospective cohort of 1,958 breast-cancer patients primary operated at our institution between 2000 and 2005. Receptors were evaluated using IHC. Steroid receptors were considered positive for any nuclear staining; HER-2 for strong (3+) membrane staining or positive fluorescence in situ hybridization (FISH). Kaplan-Meier (KM) DFI curves were calculated for any relapse defined as a local, regional, contralateral, or distant breast cancer event for the six predefined breast cancer subgroups: ER + PR + HER-2 - (PPN), ER + PR - HER-2 - (PNN), ER + PR + HER-2 + (PPP), ER - PR - HER-2 - (NNN), ER - PR - HER-2 + (NNP), and ER + PR - HER-2 + (PNP). P-values were calculated for comparison of the six different survival curves using two possible adaptations for multiple testing. A multivariate model for the receptors predicting DFI did incorporate local and systemic adjuvant therapy.

RESULTS

Median patient age was 57 years (ranges 26-96) and median FU was 3.35 years. Overall, DFI at median FU was 91%; 94% for PPN, 89% for PNN, 86% for NNN, 81% for PPP, 80% for PNP, and 76% for NNP cases. Some receptor subgroups had a significantly better DFI than others based on multiple testing, especially when the PPN group was compared against the four most frequent subtypes. The multivariate model with local and systemic adjuvant therapy confirmed the prognostic value of ER, PR, and HER-2 for short-term DFI.

CONCLUSION

It is possible to distinguish short-term prognostic breast cancer subgroups only on the basis of ER, PR, and HER-2 even when stratified for local and systemic adjuvant therapy. While gene expression profiles based on microarray data of over hundreds of genes will probably teach us much about breast cancer biology, heterogeneity, and prognosis, we emphasize the important short-term prognostic value of currently used IHC markers for ER, PR, and HER-2.

Saliva versus serum estradiol: implications for research studies using postmenopausal women

OBJECTIVE

The authors investigated saliva as a potentially reliable medium for estradiol (E2) measurements in postmenopausal women. The goal of this study was to determine whether or not saliva could be used in studies of postmenopausal women in place of serum samples. Specifically, the authors wondered whether or not saliva and serum E2, obtained simultaneously from samples collected from postmenopausal women, would correlate.

DESIGN

Samples of saliva and serum were collected simultaneously from 43 postmenopausal women. 31 were regular users of estrogen therapy (ET), 12 used no ET. Pearson's correlation coefficients were conducted to determine the degree of relationship between saliva and serum samples among ET users and non-users.

RESULTS

Among ET users saliva and serum E2 levels were significantly and positively correlated (r = 0.81, p < 0.0001). The two E2 values were not significantly correlated among ET non-users (r = 0.32, p < 0.31).

CONCLUSIONS

These data suggest that saliva E2 may be a fairly robust predictor of serum E2, but only among postmenopausal women who use ET.

Combining trastuzumab (Herceptin) with hormonal therapy in breast cancer: what can be expected and why?

Hormonal therapy and the humanised anti-HER2 monoclonal antibody trastuzumab (Herceptin) represent one of the oldest and one of the newest treatment modalities for breast cancer, respectively. Recent data have suggested that HER2 overexpression is associated with resistance to hormonal therapy and there is considerable preclinical evidence to support the existence of interaction or 'cross talk' between HER2 and estrogen-receptor (ER) signalling pathways in breast cancer. Preclinical data also demonstrate that adding trastuzumab to hormonal therapy results in greater antitumour activity than either agent alone. The existence of an inverse relationship between ER expression and HER2 overexpression has also been well established clinically. Thus, a range of clinical trials are now ongoing to determine whether the addition of trastuzumab to hormonal therapy will provide breast cancer patients with benefits in clinical practice. This review describes the rationale for these trials and discusses the potential of therapeutic regimens combining trastuzumab with hormonal therapy.

Kinetics of Inhibition of Glutamate Uptake by Antioestrogens

The antioestrogens, tamoxifen and its more recent homologue toremifene, are used in the therapy of breast cancer. Tamoxifen has been reported to cause retinal changes as side effects. Both compounds inhibited glutamate uptake in retinal pigment epithelial cells, and the present study was conducted to clarify the mechanism of this inhibition. Retinal pigment epithelial cells are part of the blood-retina barrier, and their glutamate transporters are essential for retinal glutamate homeostasis. Glutamate uptake was investigated in human retinal pigment epithelial cell line D407 and in cultured pig retinal pigment epithelial cells using L-[3H]glutamate as a tracer. The cells were exposed to 7.5 microM tamoxifen and toremifene. beta-Hydroxyaspartate, a transportable inhibitor of glutamate transport, was used as a reference compound. In kinetic analyses, beta-hydroxyaspartate increased the Km constant for glutamate transport. Tamoxifen and toremifene exhibited the same effect, which indicates that inhibition evoked by them is also competitive in nature. Both drugs were more effective in the human retinal pigment epithelial cell line than in the pig retinal pigment epithelial cells. The results show for the first time that the antioestrogens tamoxifen and toremifene could possibly hamper glutamate transport by replacing glutamate as the substrate.