The clinical impact of mean vessel size and solidity in breast carcinoma patients

The specific shapes of capillaries are associated with worse prognosis in patients with invasive breast cancer

Angiogenesis is considered essential for tumor progression; however, whether histological counting of blood vessel numbers, expressed as microvessel density (MVD), can be a prognostic factor in breast cancer remains controversial. It has been suggested that the specific morphology of blood vessels such as glomeruloid microvascular proliferation (GMP) is associated with clinical parameters. Here, we aimed to clarify the significance of MVD with revised immunohistochemistry and to identify new blood vessel shapes that predict prognosis in breast cancer. Four hundred and eleven primary breast cancer specimens were collected, and the sections were immunohistochemically stained with CD31 (single staining) and CD31 and Collagen IV (double staining). The prognosis of patients was examined based on the MVD value, and the presence of GMP and other blood vessels with other specific shapes. As a result, high MVD value and the presence of GMP were not associated with worse prognosis. By contrast, patients with deep-curved capillaries surrounding tumor cell nests (C-shaped) or excessively branched capillaries near tumor cell nests showed a significantly poor prognosis. The presence of these capillaries was also correlated with clinicopathological parameters such as Ki-67 index. Thus, the morphology of capillaries rather than MVD can be a better indicator of tumor aggressiveness.

Vessel size as a marker of survival in estrogen receptor positive breast cancer

PURPOSE

Angiogenesis is crucial for tumor growth and is one of the hallmarks of cancer. In this study, we analyzed microvessel density, vessel median size, and perivascular a-SMA expression as prognostic biomarkers in breast cancer.

METHODS

Dual IHC staining was performed where alpha-SMA antibodies were used together with antibodies against the endothelial cell marker CD34. Digital images of stainings were analyzed to extract quantitative data on vessel density, vessel size, and perivascular alpha-SMA status.

RESULTS

The analyses in the discovery cohort (n = 108) revealed a statistically significant relationship between large vessel size and shorter disease-specific survival (p = 0.007, log-rank test; p = 0.01, HR 3.1; 95% CI 1.3-7.4, Cox-regression analyses). Subset analyses indicated that the survival association of vessel size was strengthened in ER + breast cancer. To consolidate these findings, additional analyses were performed on a validation cohort (n = 267) where an association between large vessel size and reduced survival was also detected in ER + breast cancer (p = 0.016, log-rank test; p = 0.02; HR 2.3, 95% CI 1.1-4.7, Cox-regression analyses).

CONCLUSION

Alpha-SMA/CD34 dual-IHC staining revealed breast cancer heterogeneity regarding vessel size, vessel density, and perivascular a-SMA status. Large vessel size was linked to shorter survival in ER + breast cancer.

Angiogenic role of miR-20a in breast cancer

Background

Angiogenesis is a key process for tumor progression and a target for treatment. However, the regulation of breast cancer angiogenesis and its relevance for clinical resistance to antiangiogenic drugs is still incompletely understood. Recent developments on the contribution of microRNA to tumor angiogenesis and on the oncogenic effects of miR-17-92, a miRNA cluster, point to their potential role on breast cancer angiogenesis. The aim of this work was to establish the contribution of miR-20a, a member of miR-17-92 cluster, to tumor angiogenesis in patients with invasive breast carcinoma.

Methods

Tube-formation in vitro assays with conditioned medium from MCF7 and MDA-MB-231 breast cancer cell lines were performed after transfection with miR-20a and anti-miR20a. For clinical validation of the experimental findings, we performed a retrospective analysis of a series of consecutive breast cancer patients (n = 108) treated with neoadjuvant chemotherapy and with a full characterization of their vessel pattern and expression of angiogenic markers in pre-treatment biopsies. Expression of members of the cluster miR-17-92 and of angiogenic markers was determined by RT-qPCR after RNA purification from FFPE samples.

Results

In vitro angiogenesis assays with endothelial cells and conditioned media from breast cancer cell lines showed that transfection with anti-miR20a in MDA-MB-231 significantly decreased mean mesh size and total mesh area, while transfection with miR-20a in MCF7 cells increased mean mesh size. MiR-20a angiogenic effects were abrogated by treatment with aflibercept, a VEGF trap. These results were supported by clinical data showing that mir-20a expression was higher in tumors with no estrogen receptor or with more extensive nodal involvement (cN2-3). A higher miR-20a expression was associated with higher mean vessel size (p = 0.015) and with an angiogenic pattern consisting in larger vessels, higher VEGFA expression and presence of glomeruloid microvascular proliferations (p<0.001). This association was independent of tumor subtype and VEGFA expression.

Conclusions

Transfection of breast cancer cells with miR-20a induces vascular changes in endothelial tube-formation assays. Expression of miR-20a in breast invasive carcinomas is associated with a distinctive angiogenic pattern consisting in large vessels, anomalous glomeruloid microvascular proliferations and high VEGFA expression. Our results suggest a role for miR-20a in the regulation of breast cancer angiogenesis, and raise the possibility of its use as an angiogenic biomarker.

Reversible p53 inhibition prevents cisplatin ototoxicity without blocking chemotherapeutic efficacy

Cisplatin is a widely used chemotherapy drug, despite its significant ototoxic side effects. To date, the mechanism of cisplatin‐induced ototoxicity remains unclear, and hearing preservation during cisplatin‐based chemotherapy in patients is lacking. We found activation of the ATM‐Chk2‐p53 pathway to be a major determinant of cisplatin ototoxicity. However, prevention of cisplatin‐induced ototoxicity is hampered by opposite effects of ATM activation upon sensory hair cells: promoting both outer hair cell death and inner hair cell survival. Encouragingly, however, genetic or pharmacological ablation of p53 substantially attenuated cochlear cell apoptosis, thus preserving hearing. Importantly, systemic administration of a p53 inhibitor in mice bearing patient‐derived triple‐negative breast cancer protected auditory function, without compromising the anti‐tumor efficacy of cisplatin. Altogether, these findings highlight a novel and effective strategy for hearing protection in cisplatin‐based chemotherapy.

Continuous representation of tumor microvessel density and detection of angiogenic hotspots in histological whole-slide images

Blood vessels in solid tumors are not randomly distributed, but are clustered in angiogenic hotspots. Tumor microvessel density (MVD) within these hotspots correlates with patient survival and is widely used both in diagnostic routine and in clinical trials. Still, these hotspots are usually subjectively defined. There is no unbiased, continuous and explicit representation of tumor vessel distribution in histological whole slide images. This shortcoming distorts angiogenesis measurements and may account for ambiguous results in the literature. In the present study, we describe and evaluate a new method that eliminates this bias and makes angiogenesis quantification more objective and more efficient. Our approach involves automatic slide scanning, automatic image analysis and spatial statistical analysis. By comparing a continuous MVD function of the actual sample to random point patterns, we introduce an objective criterion for hotspot detection: An angiogenic hotspot is defined as a clustering of blood vessels that is very unlikely to occur randomly. We evaluate the proposed method in N=11 images of human colorectal carcinoma samples and compare the results to a blinded human observer. For the first time, we demonstrate the existence of statistically significant hotspots in tumor images and provide a tool to accurately detect these hotspots.

Assessing Tumor Angiogenesis in Histological Samples

Tumor neovascularization acquires their vessels through a number of processes including angiogenesis, vasculogenesis, vascular remodeling, intussusception, and possibly vascular mimicry in certain tumors. The end result of the tumor vasculature has been quantified by counting the number of immunohistochemically identified microvessels in areas of maximal vascularity, so-called hot spot. Other techniques have been developed such as Chalkley counting and the use of image analysis systems that are robust and reproducible as well as being more objective. Many of the molecular pathways that govern tumor neovascularization have been identified and many reagents are now available to study these tissue sections. These include angiogenic growth factors and their receptors and cell adhesion molecules, proteases, and markers of activated, proliferating, cytokine-stimulated, or angiogenic vessels, such as CD105. It is also possible to differentiate quiescent from active vessels. Other reagents that can identify proteins involved in microenvironmental influences such as hypoxia have also been generated. Although the histological assessment of tumor vascularity is used mostly in the research context, it may also have clinical applications if appropriate methodology and trained observers perform the studies.

A Heuristic Framework for Image Filtering and Segmentation: Application to Blood Vessel Immunohistochemistry

The blood vessel density in a cancerous tissue sample may represent increased levels of tumor growth. However, identifying blood vessels in the histological (tissue) image is difficult and time-consuming and depends heavily on the observer's experience. To overcome this drawback, computer-aided image analysis frameworks have been investigated in order to boost object identification in histological images. We present a novel algorithm to automatically abstract the salient regions in blood vessel images. Experimental results show that the proposed framework is capable of deriving vessel boundaries that are comparable to those demarcated manually, even for vessel regions with weak contrast between the object boundaries and background clutter.

Different types of tumor vessels in breast cancer: morphology and clinical value

Angiogenesis is a key factor of tumor progression. Considering, that the tumor vessels are heterogeneous and differ in morphology and clinical significance, the purpose of this research was to study of the morphological features of tumor vessels and their relationship with the clinical characteristics and morphological features of breast cancer (BC). In this pilot study the tumor samples received from 59 patients with T1–T2 stages of ductal invasive carcinomas were included. The sections were stained with hematoxylin and eosin and immunohistochemically using antibodies to CD34. The morphological features and the number of different types of tumor vessels were assessed microscopically and were compared with grade, lymph node metastasis, hormone receptors, HER2/neu status and with the presence of tumor emboli in vessels (lymphovascular invasion). We identified the following types of tumor vessels in BC: the normal microvessels, the dilated capillaries of peritumoral stroma, the atypical dilated capillaries and the “cavitary” structures (CS) type-1 and type-2 relating to the “cavitary” type of angiogenesis that was described by us earlier. The number of dilated capillaries correlated with CS type-1 (p = 0.003), CS type-2 (p = 0.002), atypical dilated capillaries (p = 0.0008) and with lymphovascular invasion (p = 0.005); the presence of atypical dilated capillaries—with CS type-1 (p < 0.00001), CS type-2 (p = 0.00004), lymphovascular invasion (p = 0.0002) and with the tumor grade (p = 0.003); the number of CS type-1—with estrogen receptor (p = 0.002) and progesterone receptor (p = 0.002) status and with lymphovascular invasion (p = 0.004); the presence of CS type-2—with positive Her2/new status (p = 0.0002) and lymphovascular invasion (p = 0.01). The density of normal microvessels was not associated with other types of tumor vessels and with clinical characteristics of BC. These data indicate that varied types of tumor vessels are associated with different morphological characteristics of BC, such as hormone receptors and HER2/neu status, lymphovascular invasion. We believe that the atypical dilated capillaries are related to the “cavitary” type of angiogenesis. The strong correlations of lymphovascular invasion with CS type-1 and atypical dilated capillaries testify that the “cavitary” type of angiogenesis may play a significant role in the formation of tumor emboli in the vessels.

Effects of conventional neoadjuvant chemotherapy for breast cancer on tumor angiogenesis

The effects of breast cancer conventional chemotherapy on tumor angiogenesis need to be further characterized. Neoadjuvant chemotherapy is an ideal model to evaluate the results of chemotherapy, allowing intra-patient direct comparison of antitumor and antiangiogenic effects. We sought to analyze the effect of neoadjuvant chemotherapy on tumor angiogenesis and its clinical significance in breast cancer. Breast cancer patients (n = 108) treated with neoadjuvant sequential anthracyclines and taxanes were studied. Pre- and post-chemotherapy microvessel density (MVD) and mean vessel size (MVS) were analyzed after CD34 immunohistochemistry and correlated with tumor expression of pro- and antiangiogenic factors (VEGFA, THBS1, HIF1A, CTGF, and PDGFA) by qRT-PCR. Angiogenic measures at diagnosis varied among breast cancer subtypes. Pre-treatment higher MVS was associated with triple-negative subtype and more advanced disease. Higher MVS was correlated with higher VEGFA (p = 0.003), while higher MVD was correlated with lower antiangiogenic factors expression (THBS1, p < 0.0001; CTGF, p = 0.001). Increased angiogenesis at diagnosis (high MVS and glomeruloid microvascular proliferation) and higher VEGFA expression were associated with tumor recurrence (p = 0.048 and 0.009, respectively). Chemotherapy-induced angiogenic response (defined as decreased MVD) was present in 35.2 % of patients. This response correlated with an increase in antiangiogenic factors (THBS1) without changes in VEGFA expression, and it was associated with tumor downstaging, but not with clinical response, pathologic complete response, or prognosis. Global effects of chemotherapy mainly consisted in an increased expression of antiangiogenic factors (THBS1, CTGF), with significant changes neither of tumor VEGFA nor of MVS. Conventionally scheduled neoadjuvant chemotherapy exerts antiangiogenic effects, through an increase in antiangiogenic factors, THBS1 and CTGF, but the expression of VEGFA is maintained after treatment. Better markers of angiogenic response and a better understanding of the cooperation of chemotherapy and antiangiogenic therapy in the neoadjuvant clinical scenario are needed.

Contrast enhanced computed tomography is indicative for angiogenesis pattern and display prognostic significance in breast cancer

Background

The Prognostic value of microvessel density in cancer remains unclear. Recent studies have suggested that the uneven distribution of microvessels in tumours caused the variation in sample selection which led to different prognostic outcome. The enhancement pattern of Contrast-enhanced computed tomography (CECT) is determined in part by the microvessel distribution in solid tumors. Therefore, survival analysis of tumors grouping by the enhancement pattern and the pattern of microvessel distribution is important.

Methods

Survival analysis grouped by the tumor enhancement pattern and the microvessel distribution was carried out in 255 patients with invasive ductal carcinoma.

Results

There were significant differences in overall survival (OS) and disease-free survival (DFS) among the homogeneous, heterogeneous and peripheral enhancement groups. There were significant differences between OS and DFS groups with uniform and uneven distributions of microvessels.

Conclusions

The distribution of microvessels in a tumor is a potential prognostic indicator in patients with breast cancer, and can be assessed by CECT prior the operation.