Ramona F. Swaby

Activity of Suberoylanilide Hydroxamic Acid Against Human Breast Cancer Cells with Amplification of Her-2

Purpose: We determined the effects of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, on hsp90 and its client proteins Her-2, AKT, and c-Raf, as well as evaluated the cytotoxic effects of cotreatment of SAHA with trastuzumab or docetaxel in human breast cancer BT-474 and SKBR-3 cells containing amplification of Her-2. Experimental Design: The cells were treated with SAHA (1.0-5.0 μmol/L) and/or trastuzumab (5-40 μg/mL) or docetaxel (5-20 nmol/L). Following this, apoptosis and the levels of p21WAF1, p27KIP1, AKT, c-Raf, and Her-2, as well as of the key regulators of apoptosis were determined. Synergistic interaction between drugs was evaluated by median dose-effect analysis. Results: Treatment with SAHA up-regulated p21WAF1 and p27KIP1 levels, increased the percentage of cells in G2-M phase of the cell cycle, as well as induced apoptosis in a dose-dependent manner. This was associated with up-regulation of the pro-death Bak and Bim, as well as with attenuation of the levels of Her-2 and XIAP, survivin, Bcl-2, and Bcl-xL proteins. SAHA treatment induced acetylation of hsp90. This reduced the chaperone association of Her-2 with hsp90, promoting polyubiquitylation and degradation of Her-2. SAHA also attenuated the levels of c-Raf and AKT. Cotreatment with SAHA significantly increased trastuzumab or docetaxel-induced apoptosis of BT-474 and SKBR-3 cells. Additionally, median dose-effect analysis revealed that cotreatment with SAHA and trastuzumab or docetaxel induced synergistic cytotoxic effects against the breast cancer cells. Conclusions: These preclinical findings support the development of SAHA in combination with docetaxel and/or trastuzumab against Her-2-amplified breast cancer.

Determination of cancer risk associated with germ line BRCA1 missense variants by functional analysis

Germ line inactivating mutations in BRCA1 confer susceptibility for breast and ovarian cancer. However, the relevance of the many missense changes in the gene for which the effect on protein function is unknown remains unclear. Determination of which variants are causally associated with cancer is important for assessment of individual risk. We used a functional assay that measures the transactivation activity of BRCA1 in combination with analysis of protein modeling based on the structure of BRCA1 BRCT domains. In addition, the information generated was interpreted in light of genetic data. We determined the predicted cancer association of 22 BRCA1 variants and verified that the common polymorphism S1613G has no effect on BRCA1 function, even when combined with other rare variants. We estimated the specificity and sensitivity of the assay, and by meta-analysis of 47 variants, we show that variants with <45% of wild-type activity can be classified as deleterious whereas variants with >50% can be classified as neutral. In conclusion, we did functional and structure-based analyses on a large series of BRCA1 missense variants and defined a tentative threshold activity for the classification missense variants. By interpreting the validated functional data in light of additional clinical and structural evidence, we conclude that it is possible to classify all missense variants in the BRCA1 COOH-terminal region. These results bring functional assays for BRCA1 closer to clinical applicability.

Circulating tumor cells in breast cancer: A tool whose time has come of age

Circulating tumor cells (CTCs) are isolated tumor cells disseminated from the site of disease in metastatic and/or primary cancers, including breast cancer, that can be identified and measured in the peripheral blood of patients. As recent technical advances have rendered it easier to reproducibly and repeatedly sample this population of cells with a high degree of accuracy, these cells represent an attractive surrogate marker of the site of disease.Currently, CTCs are being integrated into clinical trial design as a surrogate for phenotypic and genotypic markers in correlation with development of molecularly targeted therapies. As CTCs play a crucial role in tumor dissemination, translational research is implicating CTCs in several biological processes, including epithelial to mesenchymal transition. In this mini-review, we review CTCs in metastatic breast cancer, and discuss their clinical utility for assessing prognosis and monitoring response to therapy. We will also introduce their utility in pharmacodynamic monitoring for rational selection of molecularly targeted therapies and briefly address how they can help elucidate the biology of cancer metastasis.

Impact of the radiation boost on outcomes after breast-conserving surgery and radiation.

PURPOSE We examined the impact of radiation tumor bed boost parameters in early-stage breast cancer on local control and cosmetic outcomes. METHODS AND MATERIALS A total of 3,186 women underwent postlumpectomy whole-breast radiation with a tumor bed boost for Tis to T2 breast cancer from 1970 to 2008. Boost parameters analyzed included size, energy, dose, and technique. Endpoints were local control, cosmesis, and fibrosis. The Kaplan-Meier method was used to estimate actuarial incidence, and a Cox proportional hazard model was used to determine independent predictors of outcomes on multivariate analysis (MVA). The median follow-up was 78 months (range, 1-305 months). RESULTS The crude cosmetic results were excellent in 54%, good in 41%, and fair/poor in 5% of patients. The 10-year estimate of an excellent cosmesis was 66%. On MVA, independent predictors for excellent cosmesis were use of electron boost, lower electron energy, adjuvant systemic therapy, and whole-breast IMRT. Fibrosis was reported in 8.4% of patients. The actuarial incidence of fibrosis was 11% at 5 years and 17% at 10 years. On MVA, independent predictors of fibrosis were larger cup size and higher boost energy. The 10-year actuarial local failure was 6.3%. There was no significant difference in local control by boost method, cut-out size, dose, or energy. CONCLUSIONS Likelihood of excellent cosmesis or fibrosis are associated with boost technique, electron energy, and cup size. However, because of high local control and rare incidence of fair/poor cosmesis with a boost, the anatomy of the patient and tumor cavity should ultimately determine the necessary boost parameters.

Five-year Local Control in a Phase II Study of Hypofractionated Intensity Modulated Radiation Therapy With an Incorporated Boost for Early Stage Breast Cancer

PURPOSE Conventional radiation fractionation of 1.8-2 Gy per day for early stage breast cancer requires daily treatment for 6-7 weeks. We report the 5-year results of a phase II study of intensity modulated radiation therapy (IMRT), hypofractionation, and incorporated boost that shortened treatment time to 4 weeks. METHODS AND MATERIALS The study design was phase II with a planned accrual of 75 patients. Eligibility included patients aged≥18 years, Tis-T2, stage 0-II, and breast conservation. Photon IMRT and an incorporated boost was used, and the whole breast received 2.25 Gy per fraction for a total of 45 Gy, and the tumor bed received 2.8 Gy per fraction for a total of 56 Gy in 20 treatments over 4 weeks. Patients were followed every 6 months for 5 years. RESULTS Seventy-five patients were treated from December 2003 to November 2005. The median follow-up was 69 months. Median age was 52 years (range, 31-81). Median tumor size was 1.4 cm (range, 0.1-3.5). Eighty percent of tumors were node negative; 93% of patients had negative margins, and 7% of patients had close (>0 and <2 mm) margins; 76% of cancers were invasive ductal type: 15% were ductal carcinoma in situ, 5% were lobular, and 4% were other histology types. Twenty-nine percent of patients 29% had grade 3 carcinoma, and 20% of patients had extensive in situ carcinoma; 11% of patients received chemotherapy, 36% received endocrine therapy, 33% received both, and 20% received neither. There were 3 instances of local recurrence for a 5-year actuarial rate of 2.7%. CONCLUSIONS This 4-week course of hypofractionated radiation with incorporated boost was associated with excellent local control, comparable to historical results of 6-7 weeks of conventional whole-breast fractionation with sequential boost.

Young age is not associated with increased local recurrence for DCIS treated by breast-conserving surgery and radiation†

We report local recurrence (LR) after breast‐conserving surgery and radiation (BCS + RT) for ductal carcinoma in situ (DCIS) to determine outcomes for patients aged ≤40 years compared with older women.

Lymphatic Space Invasion is Not an Independent Predictor of Outcomes in Early Stage Breast Cancer Treated by Breast-Conserving Surgery and Radiation

Abstract:  To study the prognostic importance of lymphovascular invasion (LVI) in early stage breast cancer after conservative surgery and radiation. From 2/80 to 8/07, 1,478 patients were treated with breast‐conserving surgery and radiation with or without systemic therapy. Study eligibility included breast conservation, whole breast postoperative radiation, T1–T2 disease, and known LVI status. Endpoints were 5‐ and 10‐year actuarial outcomes for local control and survival. LVI was present in 427 patients and absent in 1,051 patients. Median follow‐up was 68 and 69 months, respectively. Patients with LVI had a younger median age, were more often pre‐ or perimenopausal, T2, physically palpable, invasive ductal, node positive, grade 3, and treated with chemotherapy compared with patients without LVI. The 5‐ and 10‐year local‐regional recurrence was 4.5% and 9.6% with LVI compared with 1.6% and 5.6% without LVI (p = 0.01). The 5‐ and 10‐year overall survival was 83% and 68% for LVI and 91% and 80% for no LVI, respectively (p < 0.0001). Multivariate analysis showed that LVI was not an independent predictor of local‐regional control (p = 0.0697) or survival (p = 0.1184). LVI in breast cancer is found in association with other worse prognostic factors for outcome, is associated with a modest increase in local‐regional recurrence, but is not an independent predictor of local‐regional recurrence or survival on multivariate analysis.

History of Smoking is Associated with Younger Age at Diagnosis of Breast Cancer

Abstract:  Smoking tobacco has been associated with incidence, response and outcomes after treatment of some cancers. We hypothesized that tobacco use could result in an observable effect on breast cancer stage and characteristics at diagnosis. There were 6,000 patients with Tis‐4, N0‐3 breast cancers who presented to a comprehensive cancer center at initial diagnosis between 1970 and 2006. Patients were included who had a known smoking history, and subdivided into any tobacco use 2683 (45%) or never tobacco use 3317 (55%). Analyses were performed to evaluate the association of smoking with clinical, pathologic and treatment‐related factors at cancer presentation. Median age at diagnosis for all breast cancers was 55 years, for nonsmokers was 56 years, for any smoking history was 55 years, and the subgroup of current smokers was 52 years. The difference in median age for current smokers versus nonsmokers was statistically significant (p < 0.0001). The probability of age <55 years at breast cancer diagnosis for any smoking history compared to nonsmokers was 1.2 for white patients (p < 0.0003) but 0.81 for black patients (p = 0.25). There was no statistically significant association between smoking and T stage, N stage, ER/PR status, or Her‐2/neu status, although smokers were less likely to utilize breast‐conserving treatment. Smoking was associated with a younger age at diagnosis and lower utilization of breast conservation, and observed in the subgroup of white patients but not black patients. Further efforts to clarify potential reasons for any racial differences and lower utilization of breast conservation with smoking are warranted.

Identifying breast cancer patients most likely to benefit from aromatase inhibitor therapy after adjuvant radiation and tamoxifen

The purpose of the current study was to examine patient selection for an aromatase inhibitor in breast cancer patients who were free from adverse events 5 years after treatment with tamoxifen.

By looking back we can see the way forward: enhancing the gains achieved with antihormone therapy

Sir Alexander Haddow discovered the first chemical therapy to treat cancer [1]. Based on Paul Ehrlich’s pioneering work that resulted in chemical therapy or chemotherapy to treat bacterial infections [2], Haddow investigated the therapeutic potential of numerous polycyclic hydrocarbons to cause tumour regression in experimental animals. Some compounds were effective, but the fact that they were known carcinogens prohibited further exploration in humans. Nevertheless, the triphenylethylene-based oestrogens [3] have a structural similarity to polycyclic hydrocarbons and they were also observed to cause tumour regression in animals. This was the translational basis of Haddow’s landmark clinical experiments to evaluate the efficacy of high-dose oestrogen on the growth of breast and prostate cancer. Responses were noted but Haddow later commented [4] in 1970 during the inaugural David A Karnofsky lecture that, ‘The extraordinary extent of tumour regression observed in perhaps 1% of postmenopausal cases has always been regarded as of major theoretical importance and it is a matter of some disappointment that so much of the underlying mechanisms continue to elude us.’