Emi Tokuda

Estrogen receptor-α directly regulates sensitivity to paclitaxel in neoadjuvant chemotherapy for breast cancer

Neoadjuvant chemotherapy (NAC) has become the standard treatment for advanced breast cancer. Several prognostic markers, including estrogen receptor-α (ERα), are used to predict the response to NAC. However, the molecular significance of ERα expression in the efficacy of chemotherapy is not yet fully understood. To examine this issue, we first evaluated ERα transcriptional activity in breast cancer cells derived from pre-NAC specimens using estrogen response element–green fluorescent protein (ERE–GFP) as a reporter gene, and found that, in the cases for which ERα activities determined by GFP expression were not detected or low, pCR (pathological complete response) could be achieved even though ERα protein was expressed. Next, we examined the effects of alterations in ERα expression levels on sensitivity to paclitaxel, a key drug in NAC, by stable expression of ERα in ER-negative SKBR3 cells and by siRNA-mediated down-regulation of ERα in ER-positive MCF-7 cells, and showed that ERα expression and sensitivity to paclitaxel showed an inverse correlation. We also established paclitaxel-resistant MCF-7 cell clones and found that they have higher estrogen-induced ER activity than parent cells. Paclitaxel is a microtubule-stabilizing agent, while HDAC6 (histone deacetylase 6), which we previously identified as an estrogen-regulated gene, enhances cell motility by destabilizing microtubules via deacetylation of α-tubulin. Finally, we demonstrate herein that ERα knockdown in MCF-7 cells prevents deacetylation of α-tubulin, thereby increasing sensitivity to paclitaxel. Taken together, these results suggest that ERα expression directly regulates sensitivity to paclitaxel in NAC for breast cancer via the effect on microtubule stability.

Low FOXA1 expression predicts good response to neo-adjuvant chemotherapy resulting in good outcomes for luminal HER2-negative breast cancer cases

Background:FOXA1 expression is a good prognostic marker for endocrine therapy in hormone-positive breast cancer. We retrospectively examined breast cancer patients with luminal human epidermal growth factor receptor 2 (HER2)-negative tumours, as defined by immunohistochemistry, who received neo-adjuvant chemotherapy (NAC) and investigated the relationship between treatment effects and FOXA1 expression.Methods:Biopsy specimens from 103 luminal HER2-negative tumours were immunohistochemically examined. FOXA1 effects on chemo-sensitivity were also investigated employing in vitro experiments.Results:FOXA1 and Ki67 expressions independently predicted a pathological complete response (pCR). Knockdown of FOXA1 by siRNA boosted the chemo-effect in oestrogen receptor-positive cells. The Cox hazards model revealed a pCR to be the strongest factor predicting a good patient outcome.Conclusions:Our present study showed low FOXA1 expression to be associated with a good response to NAC in luminal HER2-negative breast cancer. Improved outcomes of these patients suggest that NAC should be recommended to patients with low FOXA1 tumours.

Ki67 expression and the effect of neo-adjuvant chemotherapy on luminal HER2-negative breast cancer

BackgroundPatients with luminal HER2-negative tumours have a favourable prognosis. However, there is a subpopulation in which poorer outcomes are obtained with endocrine therapy alone. This subpopulation is considered to benefit from chemotherapy. However, the significance of chemotherapy for those with luminal tumours has decreased due to recent changes in treatment strategies. Thus, it is often difficult to determine whether we should recommend chemotherapy to such patients in clinical practice. We investigated Ki67 expression, as a means of predicting the responses of luminal HER2-negative breast cancer patients to neo-adjuvant chemotherapy (NAC), in order to identify a subpopulation that would benefit from these treatments.MethodsWe enrolled 114 luminal HER2-negative breast cancer patients undergoing surgery after NAC. Biomarkers were examined using biopsy specimens obtained prior to treatment, to avoid any chemotherapy-related effects. Chemotherapy effects were determined employing operative specimens and we defined pathological complete response (pCR) as invasive nest disappearance, based only on the primary breast tumour. We applied receiver operating characteristic curve analysis to data from our 114 patients, to investigate Ki67 expression as a predictor of pCR.ResultsThe pCR rate was significantly higher for tumours with high Ki67 expression (p < 0.01) and all patients who obtained pCR remained recurrence-free during the median 58-month observation period. We identified 35% as the Ki67 cut-off value which distinguishes those with a pCR from other cases. Another dataset, comprised of 196 patients with a median 29-month observation period, was recruited for validation. Disease-free survival was found to be significantly (p < 0.01) lower in the patients with tumours in which Ki67 expression was higher than 35%.ConclusionOur results raise the possibility of the luminal HER2-negative subpopulation with Ki67 expression higher than 35% benefiting from chemotherapy, as evidenced by improved survival.

Significance of HER2 Protein Examination in Ductal Carcinoma In Situ

BACKGROUND HER2 expression is routinely checked in ductal carcinoma in situ, as in invasive ductal carcinoma. However, the effect of HER2 status in ductal carcinoma in situ on the development of malignancy and the significance of overexpression of HER2 are still not clear. MATERIALS AND METHODS We experienced 103 cases that were diagnosed as pure ductal carcinoma in situ from operative specimens in the 2-y period from 2006 to 2007. We examined their HER2 status and other markers. We added 38 cases of ductal carcinoma in situ with small invasive disease 5mm or less in diameter as subjects. We also examined how accurately HER2 status in biopsy specimens predicted the existence of an invasive component. RESULTS In pure ductal carcinoma in situ, tumors that were comedo type, high grade, or ER negative showed a high frequency of HER2 overexpression. In cases with small invasion, HER2 expression was higher than that in pure ductal carcinoma in situ. Among cases that were diagnosed as ductal carcinoma in situ by biopsy, 28% had invasive disease in operative specimens. In tumors that were palpable, large, or expressed HER2 3+ in biopsy samples, invasive disease was frequently observed in operative specimens. CONCLUSIONS Overexpression of HER2 in ductal carcinoma in situ might not always be necessary for progression to invasive ductal carcinoma. To clarify the significance of HER2 examination in DCIS, further investigations of the potential for invasive ductal carcinoma and the prognosis are still needed.

Differences in Ki67 expressions between pre- and post-neoadjuvant chemotherapy specimens might predict early recurrence of breast cancer

The prognosis of breast cancer patients not obtaining a pathological complete response (pCR) with neoadjuvant chemotherapy (NAC) is poorer than that of pCR patients. Identifying new prognostic factors for non-pCR patients is important because fractions of this population might benefit from novel adjuvant treatments currently under development. High Ki67 expression in remnant disease after NAC has been described as a poor prognostic factor. Studies have shown that a reduction in Ki67 expression is more often observed in good responders to chemotherapy. We hypothesized that the change in Ki67 expression might be useful for predicting patient outcomes and thus retrospectively examined pairs of biopsy and surgical specimens of breast tissue from individual patients. One hundred sixteen patients with remnant invasive disease in the breast, who received NAC and underwent surgery at our institution, were retrospectively examined. Differences in Ki67 expression between pre- and post-NAC specimens were analyzed in relation to patient outcomes. The mean Ki67 expression value after NAC was higher in patients who developed metastasis than in those without metastasis (P<.01). Tumors showing higher Ki67 expression in the surgical than in the biopsy specimen were more frequent in patients with metastasis (P<.01). This trend was more obvious in patients who developed metastasis within 1 year after surgery. Our results indicate that a difference in Ki67 expressions after versus before NAC might be an important predictor of early metastasis. Evaluating not only absolute Ki67 values, but also any changes in response to NAC, may improve the prediction of patient outcomes.

Activated Caspase 3 Expression in Remnant Disease After Neoadjuvant Chemotherapy May Predict Outcomes of Breast Cancer Patients

BackgroundA number of studies have indicated that patients obtaining a pathological complete response (pCR) from neoadjuvant chemotherapy (NAC) have a good prognosis; however, prognostic factors for non-pCR patients are not yet well-established. By examining remnant cancer in non-pCR patients, the expression of cleaved Caspase 3 (Casp3), an activated apoptotic marker, was immunohistochemically investigated to determine whether this protein has the potential to serve as a novel marker for predicting patient outcomes.MethodsWe investigated 218 patients with invasive breast cancer who received NAC and underwent surgery during the 2006 through 2008 period at our institution. Following surgery, standard adjuvant endocrine therapy was administered if a tumor was hormone receptor-positive. Casp3 was evaluated in remnant cancer based on the number of positive cells in five high-power fields.ResultspCR was obtained in 49 patients, and 50 of the 169 non-pCR patients developed recurrences during the median 82-month observation period. We found large tumor size, lymph node involvement, lymph vessel invasion, estrogen receptor-negative, progesterone receptor-negative, high Ki67 and high Casp3 expression to be factors related to tumor recurrence. A logistic regression model revealed that lymph node involvement, as well as high Ki67 and Casp3, to be factors independently predicting recurrence, while lymph vessel invasion and high Ki67 expression were found to be related to breast cancer mortality.ConclusionsPatients with remnant cancer showing high Casp3 expression had poor outcomes. Our results showed that Casp3 is a potential prognostic marker for non-pCR patients.

Menstrual cycle could affect Ki67 expression in estrogen receptor-positive breast cancer patients

Background Ki67 is a potent prognostic marker for determining systemic treatment of patients with hormone receptor-positive breast cancer. However, evaluation of Ki67 expression can be difficult, due mostly to its heterogeneity. The Ki67 expression level, which indicates that a cell is undergoing division (cell cycle), rises when proliferation activity increases. Thus, Ki67 expression might be affected by hormonal stimuli. We hypothesised that Ki67 expression level might change during the menstrual cycle. We examined pairs of biopsy and surgical specimens from individual patients to evaluate this hypothesis. Methods First, the effects of estradiol on Ki67 expression in breast cancer cell lines were examined employing immunocytochemistry and Western blotting. Next, differences in Ki67 expression between biopsy and surgical specimens from 131 patients with estrogen receptor-positive tumours were retrospectively examined. Results In vitro experiments showed Ki67 expression in estrogen receptor-positive cancer cells to be dependent on estradiol stimulation. Ki67 expression was higher in biopsy samples collected in the luteal phase than in those from other phases. When biopsy and surgical samples were obtained at different times during the menstrual cycle in the same individual, there were differences in Ki67 expression between these samples. Those collected in the luteal phase showed higher Ki67 expression than samples obtained during other phases (p<0.01). Conclusions Ki67 expression varied in the same patients according to menstrual cycle phase. Our results suggest that Ki67 expression in estrogen receptor-positive breast cancer should be carefully assessed bearing in mind the patients menstrual cycle, since the interpretation of expression could affect treatment decisions.

Application of a 70-Gene Expression Profile to Japanese Breast Cancer Patients.

Background: As data on using MammaPrint®, a 70-gene expression profile for molecular subtyping of breast cancer, are limited in Japanese patients, we aimed to determine the gene profiles of Japanese patients using MammaPrint and to investigate its possible clinical application for selecting adjuvant treatments. Patients and Methods: 50 women treated surgically at our institution were examined. The MammaPrint results were compared with the St Gallen 2007 and intrinsic subtype risk categorizations. Results: Of 38 cases judged to be at intermediate risk based on the St Gallen 2007 Consensus, 11 (29%) were in the high-risk group based on MammaPrint. 1 of the 30 luminal A-like tumors (3%) was judged as high risk based on MammaPrint results, whereas 7 of the 20 tumors (35%) categorized as luminal B-like or triple negative were in the low-risk group. There have been no recurrences to date in the MammaPrint group, and this is possibly attributable to most of the high-risk patients receiving chemotherapy that had been recommended on the basis of their MammaPrint results. Conclusions: Our results indicate that MammaPrint is applicable to Japanese patients and that it is of potential value in current clinical practice for devising individualized treatments.

Overcoming the Adverse Effects of Everolimus to Achieve Maximum Efficacy in the Treatment of Inoperable Breast Cancer: A Review of 11 Cases at Our Hospital

Everolimus is an effective treatment for advanced and/or metastatic breast cancer, especially in hormone receptor-positive cases. However, adverse events have prevented considerable numbers of clinicians from using this drug. Herein, we reviewed our clinical experiences and endeavored to identify patients in whom the benefits of everolimus treatment would outweigh these adverse events. If measures were available to prevent or minimize adverse effects prior to treatment, everolimus would be a more widely applicable drug. This retrospective study involved 11 patients in whom nonresectable or recurrent breast cancers were treated with everolimus between April 2014 and January 2016. Two patients achieved a partial response (PR) and 4 showed stable disease (SD) (1 showed long SD, i.e., > 24 weeks). The response rate was 18%, and the clinical benefit rate (PR + long SD) was 27%. Regarding adverse events, interstitial pneumonia (grade 3) developed in 3 patients (18%), necessitating treatment discontinuation. When using everolimus, it may be important to select suitable patients for whom this treatment can be continued with sufficient control of adverse events. Herein, we provide information relevant to the clinical use of everolimus based on our daily practice experiences with this agent.