Breast conserving surgery (BCS) is an effective treatment for early-stage cancers as long as the margins of the resected tissue are free of disease according to consensus guidelines for patient ...management. However, 15% to 35% of patients undergo a second surgery since malignant cells are found close to or at the margins of the original resection specimen. This review highlights imaging approaches being investigated to reduce the rate of positive margins, and they are reviewed with the assumption that a new system would need high sensitivity near 95% and specificity near 85%. The problem appears to be twofold. The first is for complete, fast surface scanning for cellular, structural, and/or molecular features of cancer, in a lumpectomy volume, which is variable in size, but can be large, irregular, and amorphous. A second is for full, volumetric imaging of the specimen at high spatial resolution, to better guide internal radiologic decision-making about the spiculations and duct tracks, which may inform that surfaces are involved. These two demands are not easily solved by a single tool. Optical methods that scan large surfaces quickly are needed with cellular/molecular sensitivity to solve the first problem, but volumetric imaging with high spatial resolution for soft tissues is largely outside of the optical realm and requires x-ray, micro-CT, or magnetic resonance imaging if they can be achieved efficiently. In summary, it appears that a combination of systems into hybrid platforms may be the optimal solution for these two very different problems. This concept must be cost-effective, image specimens within minutes and be coupled to decision-making tools that help a surgeon without adding to the procedure. The potential for optical systems to be involved in this problem is emerging and clinical trials are underway in several of these technologies to see if they could reduce positive margin rates in BCS.
Presently, the ability to study disease at the most fundamental molecular level has led to a reclassification of human cancers into numerous subtypes that vary in disease progression and response to ...therapy. Similar to most solid tumors, breast cancer is a heterogeneous disease with considerable variation in histologic and biological features. Triple-negative breast cancer (TNBC) is a subtype of breast cancer in which the estrogen receptor and progesterone receptor are not expressed, and human epidermal growth factor-receptor 2 is not amplified or overexpressed. Data derived from highly complex molecular technologies, such as microarrays and next-generation sequencing, have identified gene expression and somatic mutation profile subsets of TNBC that reflect biological behavior more accurately and may lead to further effective therapeutic targets, better prognosis, and improved outcomes. Herein, we review the genomic findings of TNBC and discuss current efforts in precision medicine as they relate to TNBC.
Microwave tomography recovers images of tissue dielectric properties, which appear to be specific for breast cancer, with low-cost technology that does not present an exposure risk, suggesting the ...modality may be a good candidate for monitoring neoadjuvant chemotherapy.
Eight patients undergoing neoadjuvant chemotherapy for locally advanced breast cancer were imaged longitudinally five to eight times during the course of treatment. At the start of therapy, regions of interest (ROIs) were identified from contrast-enhanced magnetic resonance imaging studies. During subsequent microwave examinations, subjects were positioned with their breasts pendant in a coupling fluid and surrounded by an immersed antenna array. Microwave property values were extracted from the ROIs through an automated procedure and statistical analyses were performed to assess short term (30 days) and longer term (four to six months) dielectric property changes.
Two patient cases (one complete and one partial response) are presented in detail and demonstrate changes in microwave properties commensurate with the degree of treatment response observed pathologically. Normalized mean conductivity in ROIs from patients with complete pathological responses was significantly different from that of partial responders (P value = 0.004). In addition, the normalized conductivity measure also correlated well with complete pathological response at 30 days (P value = 0.002).
These preliminary findings suggest that both early and late conductivity property changes correlate well with overall treatment response to neoadjuvant therapy in locally advanced breast cancer. This result is consistent with earlier clinical outcomes that lesion conductivity is specific to differentiating breast cancer from benign lesions and normal tissue.
Background
Malignant phyllodes tumors of the breast are unusual neoplasms, with an incidence of approximately 500 cases annually in the United States. Published local recurrence rates after ...margin-negative breast-conserving resections of borderline malignant and malignant phyllodes tumors are unacceptably high, at 24 and 20%, respectively. It is uncertain whether radiotherapy after resection of phyllodes tumors is beneficial.
Methods
We prospectively enrolled patients who were treated with a margin-negative breast-conserving resection of borderline malignant or malignant phyllodes tumors to adjuvant radiotherapy. The primary endpoint was local recurrence.
Results
Forty-six women were treated at 30 different institutions. The mean patient age was 49 years (range, 18–76 years). Thirty patients (65%) had malignant phyllodes tumors; the rest were borderline malignant. The mean tumor diameter was 3.7 cm (range, .8–11 cm). Eighteen patients had a negative margin on the first excision. The median size of the negative margin was .35 cm (range, <.1–2 cm). Twenty-eight patients underwent a re-excision because of positive margins in the initial resection. Two patients died of metastatic phyllodes tumor. During a median follow-up of 56 months (range, 12–129 months), none of the 46 patients developed a local recurrence (local recurrence rate, 0%; 95% confidence interval, 0–8).
Conclusions
Margin-negative resection combined with adjuvant radiotherapy is very effective therapy for local control of borderline and malignant phyllodes tumors. The local recurrence rate with adjuvant radiotherapy was significantly less than that observed in reported patients treated with margin-negative resection alone.
We previously described the expression of CD36 and LPL by breast cancer (BC) cells and tissues and the growth-promoting effect of VLDL observed only in the presence of LPL. We now report a model in ...which LPL is bound to a heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to internalize VLDLs via receptor-mediated endocytosis. We also demonstrate that gene-expression programs for lipid synthesis versus uptake respond robustly to triglyceride-rich lipoprotein availability. The literature emphasizes de novo FA synthesis and exogenous free FA uptake using CD36 as paramount mechanisms for lipid acquisition by cancer cells. We find that the uptake of intact lipoproteins is also an important mechanism for lipid acquisition and that the relative reliance on lipid synthesis versus uptake varies among BC cell lines and in response to VLDL availability. This metabolic plasticity has important implications for the development of therapies aimed at the lipid dependence of many types of cancer, in that the inhibition of FA synthesis may elicit compensatory upregulation of lipid uptake. Moreover, the mechanism that we have elucidated provides a direct connection between dietary fat and tumor biology..
Somatic mutation analysis is standard of practice for solid tumors in order to identify therapeutic sensitizing and resistance mutations. Our laboratory routinely performed standalone PCR-based ...methods for mutations in several genes. Rapid discovery and introduction of new therapeutics has demanded additional genomic information for adequate management of the cancer patient. We evaluated a next generation sequencing assay, the Ion Torrent AmpliSeq Cancer Hotspot Panelv2 (CHPv2), capable of identifying multiple somatic mutations in 50 genes in a single assay.
Accuracy, precision, limit of detection, and specificity were evaluated using DNA from well-characterized cell lines, genetically engineered cell lines fixed and embedded in paraffin, and previously tested mutation positive or negative, formalin-fixed, paraffin-embedded (FFPE) tissues. Normal kidney, tonsil and colon FFPE tissues were used as controls.
Accuracy studies showed 100% concordance in each patient sample between previous PCR results and the corresponding variants identified using the Ion Torrent panel. Precision studies gave consistent results when libraries were prepared from the same original DNA and were run on multiple 316 chips. The limit of detection was determined to be 5% for single nucleotide variants (SNVs) and 20% for insertions and deletions (indels). Specificity studies using normal FFPE tissue previously tested by PCR methods were also 100%.
We have evaluated the performance of the AmpliSeq Cancer Panel Hotspotv2 and show that it is suitable for clinical testing. This next generation sequencing panel has allowed the laboratory to consolidate a broader range of molecular oncology testing to a single platform and single assay.
Although it is established that fatty acid (FA) synthesis supports anabolic growth in cancer, the role of exogenous FA uptake remains elusive. Here we show that, during acquisition of resistance to ...HER2 inhibition, metabolic rewiring of breast cancer cells favors reliance on exogenous FA uptake over de novo FA synthesis. Through cDNA microarray analysis, we identify the FA transporter CD36 as a critical gene upregulated in cells with acquired resistance to the HER2 inhibitor lapatinib. Accordingly, resistant cells exhibit increased exogenous FA uptake and metabolic plasticity. Genetic or pharmacological inhibition of CD36 suppresses the growth of lapatinib-resistant but not lapatinib-sensitive cells in vitro and in vivo. Deletion of Cd36 in mammary tissues of MMTV-neu mice significantly attenuates tumorigenesis. In breast cancer patients, CD36 expression increases following anti-HER2 therapy, which correlates with a poor prognosis. Our results define CD36-mediated metabolic rewiring as an essential survival mechanism in HER2-positive breast cancer.
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•Lapatinib-resistant breast cancer cells upregulate CD36 expression for survival•Targeting CD36 re-sensitizes lapatinib-resistant cells to HER2-inhibition•Deletion of Cd36 significantly attenuates MMTV-neu-driven mammary tumor growth•CD36 is induced by HER2-targeted therapy and predicts poor clinical prognosis
The functional significance of lipid metabolism in cancer cells is not fully understood. Feng et al. show that the fatty acid transporter CD36 is essential for survival of breast cancer cells during anti-HER2 therapy, highlighting the role of lipid metabolism in acquired resistance to targeted therapy.
Historically, ductal carcinoma in situ (DCIS) of the breast has been managed aggressively with surgery and radiotherapy because of a risk of progression to invasive ductal carcinoma. However, this ...treatment paradigm has been challenged by overtreatment concerns and evidence that suggests that DCIS can be stratified according to risk of recurrence or risk of progression to invasive disease. Traditional methods of risk stratification include histologic grade and hormone receptor status. Recent technological advancements have enabled an era of precision medicine, where DCIS can be molecularly analyzed by tools, such as next-generation DNA and RNA sequencing, to identify molecular biomarkers for risk stratification. These findings have led to the development of tools such as the Oncotype DX Breast DCIS Score, a gene expression-based assay with the potential to prevent overtreatment in low-risk disease.
High positive margin rates in oncologic breast-conserving surgery are a pressing clinical problem. Volumetric X-ray scanning is emerging as a powerful ex vivo specimen imaging technique for analyzing ...resection margins, but X-rays lack contrast between non-malignant and malignant fibrous tissues. In this study, combined micro-CT and wide-field optical image radiomics were developed to classify malignancy of breast cancer tissues, demonstrating that X-ray/optical radiomics improve malignancy classification. Ninety-two standardized features were extracted from co-registered micro-CT and optical spatial frequency domain imaging samples extracted from 54 breast tumors exhibiting seven tissue subtypes confirmed by microscopic histological analysis. Multimodal feature sets improved classification performance versus micro-CT alone when adipose samples were included (AUC = 0.88 vs. 0.90; p-value = 3.65e-11) and excluded, focusing the classification task on exclusively non-malignant fibrous versus malignant tissues (AUC = 0.78 vs. 0.85; p-value = 9.33e-14). Extending the radiomics approach to high-dimensional optical data-termed "optomics" in this study-offers a promising optical image analysis technique for cancer detection. Radiomic feature data and classification source code are publicly available.
Many types of cancer cells require a supply of fatty acids (FA) for growth and survival, and interrupting de novo FA synthesis in model systems causes potent anticancer effects. We hypothesized that, ...in addition to synthesis, cancer cells may obtain preformed, diet-derived FA by uptake from the bloodstream. This would require hydrolytic release of FA from triglyceride in circulating lipoprotein particles by the secreted enzyme lipoprotein lipase (LPL), and the expression of CD36, the channel for cellular FA uptake. We find that selected breast cancer and sarcoma cells express and secrete active LPL, and all express CD36. We further show that LPL, in the presence of triglyceride-rich lipoproteins, accelerates the growth of these cells. Providing LPL to prostate cancer cells, which express low levels of the enzyme, did not augment growth, but did prevent the cytotoxic effect of FA synthesis inhibition. Moreover, LPL knockdown inhibited HeLa cell growth. In contrast to the cell lines, immunohistochemical analysis confirmed the presence of LPL and CD36 in the majority of breast, liposarcoma, and prostate tumor tissues examined (n = 181). These findings suggest that, in addition to de novo lipogenesis, cancer cells can use LPL and CD36 to acquire FA from the circulation by lipolysis, and this can fuel their growth. Interfering with dietary fat intake, lipolysis, and/or FA uptake will be necessary to target the requirement of cancer cells for FA.
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