Tailoring radiotherapy according to cancer subtypes

Differential expression of the BCAT isoforms between breast cancer subtypes

Background

Biological characterisation of breast cancer subtypes is essential as it informs treatment regimens especially as different subtypes have distinct locoregional patterns. This is related to metabolic phenotype, where altered cellular metabolism is a fundamental adaptation of cancer cells during rapid proliferation. In this context, the metabolism of the essential branched-chain amino acids (BCAAs), catalysed by the human branched-chain aminotransferase proteins (hBCAT), offers multiple benefits for tumour growth. Upregulation of the cytosolic isoform of hBCAT (hBCATc), regulated by c-Myc, has been demonstrated to increase cell migration, tumour aggressiveness and proliferation in gliomas, ovarian and colorectal cancer but the importance of the mitochondrial isoform, hBCATm has not been fully investigated.

Methods

Using immunohistochemistry, the expression profile of metabolic proteins (hBCAT, IDH) was assessed between breast cancer subtypes, HER2 + , luminal A, luminal B and TNBC. Correlations between the percentage and the intensity of protein expression/co-expression with clinical parameters, such as hormone receptor status, tumour stage, lymph-node metastasis and survival, were determined.

Results

We show that hBCATc expression was found to be significantly associated with the more aggressive HER2 + and luminal B subtypes, whilst hBCATm and IDH1 associated with luminal A subtype. This was concomitant with better prognosis indicating a differential metabolic reliance between these two subtypes, in which enhanced expression of IDH1 may replenish the α-ketoglutarate pool in cells with increased hBCATm expression.

Conclusion

The cytosolic isoform of BCAT is associated with tumours that express HER2 receptors, whereas the mitochondrial isoform is highly expressed in tumours that are ER + , indicating that the BCAT proteins are regulated through different signalling pathways, which may lead to the identification of novel targets for therapeutic applications targeting dysregulated cancer metabolism.

Role of Oxycodone Hydrochloride in Treating Radiotherapy-Related Pain

Radiotherapy is commonly used to treat cancer patients. Besides the curable effect, radiotherapy also could relieve the pain of cancer patients. However, cancer pain is gradually alleviated about two weeks after radiotherapy. In addition, cancer patients who receive radiotherapy may also suffer from pain flare or radiotherapy-induced side effects such as radiation esophagitis, enteritis, and mucositis. Pain control is reported to be inadequate during the whole course of radiotherapy (before, during, and after radiotherapy), and quality of life is seriously affected. Hence, radiotherapy is suggested to be combined with analgesic drugs in clinical guidelines. Previous studies have shown that radiotherapy combined with oxycodone hydrochloride can effectively alleviate cancer pain. In this review, we firstly presented the necessity of analgesia during the whole course of radiotherapy. We also sketched the role of oxycodone hydrochloride in radiotherapy of bone metastases and radiotherapy-induced oral mucositis. Finally, we concluded that oxycodone hydrochloride shows good efficacy and tolerance and could be used for pain management before, during, and after radiotherapy.

Matrix metalloproteases and TIMPs as prognostic biomarkers in breast cancer patients treated with radiotherapy: A pilot study

Breast cancer (BC) is the most common tumour in women and one of the most important causes of cancer death worldwide. Radiation therapy (RT) is widely used for BC treatment. Some proteins have been identified as prognostic factors for BC (Ki67, p53, E‐cadherin, HER2). In the last years, it has been shown that variations in the expression of MMPs and TIMPs may contribute to the development of BC. The aim of this pilot work was to study the effects of RT on different MMPs (‐1, ‐2, ‐3, ‐7, ‐8, ‐9, ‐10, ‐12 and ‐13) and TIMPs (‐1 to ‐4), as well as their relationship with other variables related to patient characteristics and tumour biology. A group of 20 BC patients treated with RT were recruited. MMP and TIMP serum levels were analysed by immunoassay before, during and after RT. Our pilot study showed a slight increase in the levels of most MMP and TIMP with RT. However, RT produced a significantly decrease in TIMP‐1 and TIMP‐3 levels. Significant correlations were found between MMP‐3 and TIMP‐4 levels, and some of the variables studied related to patient characteristics and tumour biology. Moreover, MMP‐9 and TIMP‐3 levels could be predictive of RT toxicity. For this reason, MMP‐3, MMP‐9, TIMP‐3 and TIMP‐4 could be used as potential prognostic and predictive biomarkers for BC patients treated with RT.

Inflammatory breast cancer outcomes by breast cancer subtype: a population-based study

AIM

To assess the outcomes of breast cancer subtype in inflammatory breast cancer (IBC).

METHODS

We retrospectively assessed IBC patients from the SEER program.

RESULTS

We identified 626 patients, including 230 (36.7%),100 (17.6%), 113 (18.1%), and 173 (27.6%) patients with HoR+/HER2-, HoR+/HER2+, HoR-/HER2+, and HoR-/HER2- subtype disease, respectively. Multivariate analysis demonstrated that, using HoR+/HER2- subtype as reference, patients with HoR+/HER2+ subtype had better breast cancer-specific survival (BCSS) and overall survival (OS), and patients with HoR-/HER2- subtype had worse BCSS and OS, while BCSS and OS were comparable for HoR-/HER2+ subtype. Similar trends were observed in patients who received surgery, radiotherapy, chemotherapy or trimodality therapy.

CONCLUSION

Breast cancer subtype is clinically useful for predicting survival outcome in IBC. The HoR+/HER2- subtype shows poorer survival outcome than HoR+/HER2+ subtype.

Comparison of Local Recurrence Among Early Breast Cancer Patients Treated With Electron Intraoperative Radiotherapy vs Hypofractionated Photon Radiotherapy an Observational Study

Purpose

To evaluate local recurrence (LR) in women with early breast cancer (BC) who underwent intraoperative radiation therapy with electrons particles (IORT-E) or adjuvant hypofractionated external radiotherapy (HYPOFX).

Materials and methods

We retrospectively analyzed 470 patients with early BC treated at our center from September 2009 to December 2012. 235 women were treated with breast-conserving surgery and immediate IORT-E (21 Gy/1 fraction) while 235 patients underwent wide excision followed by hypofractionated whole-breast irradiation. Radiotherapy modality was chosen according to an individualized decision based on tumor features, stage, technical feasibility, age, and acceptance to be enrolled in the IORT-E group.

Results

After a median follow-up of 6 years, we observed 8 (3.4%) and 1 (0.42%) LR in the IORT-E and in the HYPOFX group (p = 0.02), respectively. The two groups differed in the prevalence of clinical characteristics (p < 0.05): age, tumor size, surgical margins, receptors, ki67, and histology. 4 and 1 woman in the IORT-E and HYPOFX group died of BC, respectively (p = 0.167). OS and DFS hazard ratio [HR] were 2.14 (95% IC, 1.10–4.15) and 2.09 (95% IC, 1.17–3.73), respectively.

Conclusion

Our comparison showed that IORT-E and HYPOFX are two effective radiotherapy modalities after conservative surgery in early BC. However, at 6 years a significant higher rate of LR occurred in patients submitted to IORT-E with respect to HYPOFX. This finding may be correlated to some subsets of patients who, depending on the biological characteristics of the BC, may be less suitable to IORT-E.

Protein biomarkers for subtyping breast cancer and implications for future research

INTRODUCTION

Breast cancer subtypes are currently defined by a combination of morphologic, genomic, and proteomic characteristics. These subtypes provide a molecular portrait of the tumor that aids diagnosis, prognosis, and treatment escalation/de-escalation options. Gene expression signatures describing intrinsic breast cancer subtypes for predicting risk of recurrence have been rapidly adopted in the clinic. Despite the use of subtype classifications, many patients develop drug resistance, breast cancer recurrence, or therapy failure. Areas covered: This review provides a summary of immunohistochemistry, reverse phase protein array, mass spectrometry, and integrative studies that are revealing differences in biological functions within and between breast cancer subtypes. We conclude with a discussion of rigor and reproducibility for proteomic-based biomarker discovery. Expert commentary: Innovations in proteomics, including implementation of assay guidelines and standards, are facilitating refinement of breast cancer subtypes. Proteomic and phosphoproteomic information distinguish biologically functional subtypes, are predictive of recurrence, and indicate likelihood of drug resistance. Actionable, activated signal transduction pathways can now be quantified and characterized. Proteomic biomarker validation in large, well-designed studies should become a public health priority to capitalize on the wealth of information gleaned from the proteome.

Lymphovascular invasion as a negative prognostic factor for triple-negative breast cancer after surgery

Purpose

This study aimed to evaluate the prognostic effects of lymphovascular invasion (LVI) in triple-negative breast cancer (TNBC) patients who underwent surgical resection.

Materials and Methods

A total of 63 non-metastatic TNBC patients who underwent surgical resection were retrospectively investigated from 2007 to 2016 in Inje University Busan Paik Hospital. Pathological tests revealed that 12 patients (19.0%) had LVI. Approximately 61.9% (n = 39) of the patients’ samples stained positive for p53. Additional chemotherapy and radiotherapy (RT) were performed in 53 (84.1%) and 47 (74.6%) patients, respectively.

Results

The median follow-up period was 39.5 months (range, 5.9 to 123.0 months). The pathological T stage (p = 0.008), N stage (p = 0.014), and p53 positivity (p = 0.044) were associated with LVI. Overall, the 3-year disease-free survival (DFS) rate and overall survival (OS) rate were 85.4% and 90.2%, respectively. Ten patients (15.9%) experienced relapse. LVI (n = 12) was associated with relapses (p = 0.016). p53 positivity was correlated with poor DFS (p = 0.048). Furthermore, LVI was related to poor DFS (p = 0.011) and OS (p = 0.001) and considered as an independent prognostic factor for DFS (p = 0.039). The 3-year DFS of patients with LVI (n = 12) was only 58.3%. Adjuvant RT minimized the negative prognostic effect of LVI on DFS (p = 0.068 [with RT] vs. p = 0.011 [without RT]).

Conclusion

LVI was related to the detrimental effects of disease progression and survival of TNBC patients. Thus, a more effective treatment strategy is needed for TNBC patients with LVI.