Clinical and histopathological factors associated with Ki-67 expression in breast cancer patients

The Role of Ki-67 in HR+/HER2- Breast Cancer: A Real-World Study of 956 Patients

Objective

This study determined the cut-off value of Ki-67 expression and discussed the interaction between Ki-67 and histological grade, further explored the prognostic role of Ki-67 in hormone receptor-positive and human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer;.

Materials and Methods

We assessed the Ki-67 expression of 956 patients with HR+/HER2 breast cancer diagnosed in the General Hospital of Ningxia Medical University from 2015 to 2019 by immunohistochemistry (IHC), The disease-free survival (DFS) was defined as the time from postoperative to the first local recurrence, distant metastasis or death of the disease. The follow-up by means of inpatient or outpatient medical records and telephone.

Results

22.5% was used as the cut-off for low/high Ki-67 expression in HR+/HER2- breast cancer. Compared with the value of 14%, which is commonly used in clinic at present, the consistency of the two values is moderate (Kappa = 0.484, P<0.001). The expression of Ki-67 was increased with the grade. (Median: G1:10%; G2:20%; G3:40%. Mean: G1:13%; G2:23%; G3:39%, P <0.001). Survival analysis was based on all patients for a median of 51 months (24-89 months), 63 cases had recurrence or metastasis during the follow-up, which 21 cases had low expression of Ki-67 and 42 cases had high expression. The patients with Ki-67 ≥ 22.5% had a 2.969 higher risk of early recurrence and metastasis than the patients with Ki-67 < 22.5%. There were 4 cases of local recurrence, 7 cases of regional lymph node metastasis, and 52 cases of distant metastasis in all patients, the common distant metastases were bone, liver, and lung, and rare metastases were adrenal gland, bone marrow, and pericardium.

Conclusion

In HR+/HER2- breast cancer, patients with Ki-67 > 22.5% have a worse prognosis and are more likely to have early recurrence and metastasis.

Synthesis and evaluation of novel thiazole moiety-containing compounds as antibreast cancer agents

Progesterone receptor (PR) agonists represent pivotal agents in trapping breast cancer cells through modulating the expression of estrogen receptor (ER). The present investigation aimed to test three novel thiadiazole-containing compounds as antibreast cancer agents. Test compounds were synthesized and abbreviated as 2-{(5-amino-1, 3, 4-thiazole-2-yl) amino}-4-(4-chloro-3-methylphenyl)-4-oxobutanoic acid (TAB), 4-(4-chloro-3-methylphenyl)-4-oxo 2-[(5-sulfanyl-1, 3, 4-thiadiazol-2-yl)] sulfanyl-butanoic acid (TSB) and 4-(4-chloro-3-methylphenyl)-4-oxo 2-[(5-sulfanyl-1, 3, 4-thiadiazol-2-yl)] sulphonyl-botanic acid (TSSB). Molecular docking of the test compounds with PR was simulated. The IC 50 of the test compounds against both Michigan cancer foundation-7 (MCF-7) and HepG2 was determined. Ehrlich solid tumor (EST) was grown in the right thigh of the mouse as a model of breast cancer in vivo . Hepatic and renal functions, besides hematological indicators, were tested. The expression of ER and ER genes in EST was determined using real-time PCR. Immunohistochemistry was carried out for the determination of Ki-67 and cyclin-dependent kinase 1 (CDK-1) in EST. Our results revealed that TAB, TSB and TSSB reduced Ehrlich tumor size by 48, 64 and 52%, respectively, compared to the EST control group. The docking scores achieved by TAB, TSB and TSSB with PR were -9.29, -9.41 and -9.24 kcal/mol, respectively. The most potent compound against MCF-7 was TSB, with an IC 50 of 3.9 g/ml. The administration of test compounds suppressed Ki-67 and CDK1, and the best effect was observed at TSB. Our findings suggest that test compounds are applicants to be antibreast cancer agents.

Correlations between serum lipid and Ki-67 levels in different breast cancer molecular subcategories

Breast cancer has the highest incidence rate among all cancer types worldwide, seriously threatening women's health. The present retrospective study explored differences in serum lipid contents in different breast cancer (BC) subcategories and their correlation with Ki-67 expression levels in patients with invasive BC with the aim of identifying novel diagnostic and prognostic indicators for personalized BC treatment. The study included 170 patients diagnosed with BC who were diagnosed with invasive BC by postoperative pathological examination. Data on patient age, body mass index and menopausal status were collected, in addition to estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 (HER2) and antigen Ki-67 expression levels and pathological tumor type. Preoperative circulating lipid levels, specifically the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and apolipoproteins A1 (ApoA1) and B (ApoB) were also obtained. Molecular subcategories of BC were grouped based on their immunohistochemistry. Differences in serum lipid levels between the groups were assessed, and correlations between serum lipid and Ki-67 expression levels were explored. While TC, LDL-C, HDL-C and ApoA1 levels differed significantly among molecular subcategories. TG and ApoB levels did not. Circulating TC and LDL-C levels were considerably higher in patients with triple-negative BC (TNBC) and HER2-positive [hormone receptor (HR)-negative] BC than in those with luminal A and B (HER2-negative) BC. Serum HDL-C levels were significantly diminished in the TNBC and HER2-positive (HR-negative) groups compared with the luminal A and B (HER2-negative) groups. ApoA1 levels were significantly reduced in cases of TNBC and HER2-positive (HR-negative) BC compared with luminal A and B BC. Ki-67 expression levels were positively correlated with circulating TC and LDL-C levels and inversely correlated with circulating HDL-C and ApoA1 levels but exhibited no correlation with serum ApoB and TG levels. The results indicate that elevated TC and LDL-C levels and diminished HDL-C and ApoA1 levels were high-risk factors in patients with TNBC and HER2-positive (HR-negative) BC, but not patients with luminal subcategories of BC. Abnormal serum lipid levels were correlated with Ki-67 expression levels, with elevated circulating TC and LDL-C levels and reduced circulating HDL-C and ApoA1 levels indicating a poor prognosis in patients with BC.

Association between epidemiological and clinico-pathological features of breast cancer with prognosis, family history, Ki-67 proliferation index and survival in Tunisian breast cancer patients

Breast cancer has different epidemio-clinical characteristics in Middle East and North-African populations compared to those reported in the Western countries. The aim of this study is to analyze the epidemiological and clinico-pathological features of breast cancer in Tunisia and to determine prognostic factors with special interest to family history, Ki-67 proliferation index and comorbidity. We retrospectively reviewed epidemiological and clinico-pathological data from patients’ medical records, treated in the Medical Oncology Department at Abderrahmane Mami Hospital, in the period 2011–2015. Data has been collected on 602 breast cancer patients and analyzed using SPSS software V.23.0. Our study showed high fractions of young breast cancer patients and cases with dense breasts. The most prevalent comorbidities observed in the studied cohort were cardiovascular diseases and diabetes. Familial breast cancer was found in 23.3% of cases and was associated with younger age at diagnosis (p<0.001) and advanced stage (p = 0.015). Ki-67 index >20% was significantly associated with early age at diagnosis, lymph node involvement (p = 0.002), advanced tumor grade (p<0.001) and high risk of relapse (p = 0.007). Ki-67 cut-off 30% predicted survival in luminal cases. Survival was worse in patients with triple negative breast cancer compared to non-triple negative breast cancer, inflammatory breast cancer compared to non-inflammatory breast cancer, moderately to poorly differentiated tumors compared to well-differentiated tumors and with positive lymph nodes compared to pN0 (p<0.05). Our study showed new insights into epidemiological and clinico-pathological characteristics of breast cancer that are not well explored in Tunisian population. Considering our findings along with the implementation of electronic health record system may improve patient health care quality and disease management.

Visual and digital assessment of Ki-67 in breast cancer tissue - a comparison of methods

Background

In breast cancer (BC) Ki-67 cut-off levels, counting methods and inter- and intraobserver variation are still unresolved. To reduce inter-laboratory differences, it has been proposed that cut-off levels for Ki-67 should be determined based on the in-house median of 500 counted tumour cell nuclei. Digital image analysis (DIA) has been proposed as a means to standardize assessment of Ki-67 staining in tumour tissue. In this study we compared digital and visual assessment (VA) of Ki-67 protein expression levels in full-face sections from a consecutive series of BCs. The aim was to identify the number of tumour cells necessary to count in order to reflect the growth potential of a given tumour in both methods, as measured by tumour grade, mitotic count and patient outcome.

Methods

A series of whole sections from 248 invasive carcinomas of no special type were immunohistochemically stained for Ki-67 and then assessed by VA and DIA. Five 100-cell increments were counted in hot spot areas using both VA and DIA. The median numbers of Ki-67 positive tumour cells were used to calculate cut-off levels for Low, Intermediate and High Ki-67 protein expression in both methods.

Results

We found that the percentage of Ki-67 positive tumour cells was higher in DIA compared to VA (medians after 500 tumour cells counted were 22.3% for VA and 30% for DIA). While the median Ki-67% values remained largely unchanged across the 100-cell increments for VA, median values were highest in the first 1-200 cells counted using DIA. We also found that the DIA100 High group identified the largest proportion of histopathological grade 3 tumours 70/101 (69.3%).

Conclusions

We show that assessment of Ki-67 in breast tumours using DIA identifies a greater proportion of cases with high Ki-67 levels compared to VA of the same tumours. Furthermore, we show that diagnostic cut-off levels should be calibrated appropriately on the introduction of new methodology.

Correlation between semiquantitative and volumetric 18F-FDG PET/computed tomography parameters and Ki-67 expression in breast cancer

OBJECTIVES

To evaluate the relationship between semiquantitative and volumetric parameters on 18F-FDG PET/computed tomography (CT), including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), tumor to liver ratio (TLR) and tumor to mediastinum ratio (TMR) with the level of Ki-67 expression in breast cancer.

PATIENT AND METHODS

We retrospectively reviewed 105 female patients with newly diagnosed breast cancer who underwent baseline 18F-FDG PET/CT and had immunohistochemical staining to determine the level of Ki-67 expression. The following PET parameters were measured (SUVmax, SUVmean, MTV, TLG, TLR and TMR) and correlated with level of Ki-67 expression.

RESULTS

Significant moderate positive correlations were found between the PET parameters (primary SUVmax, SUVmean, TLG, TLR and TMR) and level of Ki-67 expression. The primary SUVmax had the highest correlation coefficient (r = 0.461) followed by TMR (r = 0.455) and P value of <0.001 for both. In ROC analysis, primary SUVmax had the largest area under the curve (0.806, P = 0.0001), with sensitivity of 76.5 % and specificity of 75% for prediction of high Ki-67 level. In univariate analysis, all PET parameters, patient age, tumor grade, molecular subtype, estrogen receptor and progesterone receptor status were significantly associated with Ki-67 level. In multivariate regression analysis, only tumor grade [odds ratio (OR) = 20.460, 95% confidence interval (CI): 11.360-29.559, P = <0.0001], molecular subtype (OR = -21.894, 95% CI: -37.921 to -5.866, P = 0.008), SUVmax (OR = 2.299, 95% CI: 0.703-3.895, P = 0.005) and TLR (OR = -4.908, 95% CI: -9.476 to -0.340, P = 0.035) were found to be the strongest independent predictor factors for the level of Ki-67 expression and hence proliferative activity of malignant cells in breast cancer.

CONCLUSION

The semiquantitative parameters and volumetric 18F-FDG PET/CT parameter, that is, TLG correlated well with proliferation marker Ki-67 in breast cancer. 18F-FDG PET/CT imaging can be used as a useful noninvasive diagnostic tool in imaging cellular proliferation and hence may substitute for in vitro testing of molecular markers in the diagnoses and staging of breast cancer.

A novel culture method that sustains ERα signaling in human breast cancer tissue microstructures

BACKGROUND

Estrogen receptor α (ERα) signaling is a defining and driving event in most breast cancers; ERα is detected in malignant epithelial cells of 75% of all breast cancers (classified as ER-positive breast cancer) and, in these cases, ERα targeting is the main therapeutic strategy. However, the biological determinants of ERα heterogeneity and the mechanisms underlying therapeutic resistance are still elusive, hampered by the challenges in developing experimental models recapitulative of intra-tumoral heterogeneity and in which ERα signaling is sustained. Ex vivo cultures of human breast cancer tissue have been proposed to retain the original tissue architecture, epithelial and stromal cell components and ERα. However, loss of cellularity, viability and ERα expression are well-known culture-related phenomena.

METHODS

BC samples were collected and brought to the laboratory. Then they were minced, enzymatically digested, entrapped in alginate and cultured for 1 month. The histological architecture, cellular composition and cell proliferation of tissue microstructures were assessed by immunohistochemistry. Cell viability was assessed by measurement of cell metabolic activity and histological evaluation. The presence of ERα was accessed by immunohistochemistry and RT-qPCR and its functionality evaluated by challenge with 17-β-estradiol and fulvestrant.

RESULTS

We describe a strategy based on entrapment of breast cancer tissue microstructures in alginate capsules and their long-term culture under agitation, successfully applied to tissue obtained from 63 breast cancer patients. After 1 month in culture, the architectural features of the encapsulated tissue microstructures were similar to the original patient tumors: epithelial, stromal and endothelial compartments were maintained, with an average of 97% of cell viability compared to day 0. In ERα-positive cases, fibers of collagen, the main extracellular matrix component in vivo, were preserved. ERα expression was at least partially retained at gene and protein levels and response to ERα stimulation and inhibition was observed at the level of downstream targets, demonstrating active ER signaling.

CONCLUSIONS

The proposed model system is a new methodology to study ex vivo breast cancer biology, in particular ERα signaling. It is suitable for interrogating the long-term effects of anti-endocrine drugs in a set-up that closely resembles the original tumor microenvironment, with potential application in pre- and co-clinical assays of ERα-positive breast cancer.

Prognostic Importance of Ki-67 in Breast Cancer and Its Relationship with Other Prognostic Factors

Objective

The clinical feature of breast cancer is very heterogeneous because of the variable prognostic factors impact its behaviour. The aim of study is to find the prognostic importance of Ki-67 and to analyse the correlation between Ki-67 index and the other conventional prognostic factors in breast cancer patients.

Materials and Methods

Between 2010 and 2017, patients with invasive ductal carcinoma who received radiotherapy after surgery were included in study. A single pathologist re-defined of all cases retrospectively. Ki-67 were established three categories based on Ki-67 levels: low (<10%), intermediate (10-25%) and high (>25%).

Results

A total of 258 patients were included. 46 of 258 (18%) patients were in low, 82 of 258 (32%) patients were in intermediate and 130 of 258 (50%) patients were in high Ki-67 group. There were no correlations between menopausal status, age, and Ki-67 level. Low-pT stages tended to have low Ki-67 expression (p=0.07). Low-pN stages correlated with low Ki-67 values (p=0.007). Patients with ECE (+) were prone to have higher Ki-67 values (p=0.02). The significant correlation was seen between Ki-67 and tumour grading (p=<0.0001). Patients with LVI (+) had higher Ki-67 expression (p=0.007). Luminal A tumours were correlated with low Ki-67 group (p=<0.0001). Ki-67 values had significant effect on DFS (p=0.03) but not OS (p=0.09).

Conclusion

This study showed that high Ki-67 expression is associated with higher pT-stage, higher pN-stage, higher grade, ER/PR negativity, HER2/neu positivity, ECE and LVI positivity. The prognostic impact of Ki-67 was only demonstrated for DFS.

Breast Cancer in Turkey; An Analysis of 20.000 Patients with Breast Cancer

Objective

Breast cancer is the most common type of cancer and the leading cause of cancer-related deaths in women in Turkey. This study presents the characteristics of patients registered in National Breast Cancer Registry Program of Turkish Federation of Breast Diseases Societies.

Materials and Methods

The registry contains 242 variables under 10 categories and 699 questions. Patients were recorded (online and offline) from nationwide breast centers around Turkey.

Results

Twenty-thousand patients were registered between May 2005 and April 2017 at 36 centers. After data cleaning, 19,503 women were included in the study. The median age at diagnosis was 51 [14-97]; 17.2% were younger than 40 and 37.2% were premenopausal; 13.6% were nulliparous. Breast conserving surgery rate was 39.3%. Histopathology was invasive ductal cancer in 77%. Majority of patients had stage II cancer (48.3%). Estrogen, progesterone and HER-2 receptor positivity rates in invasive breast cancer were 72.5%, 62.5% and 21.8%, respectively. The mean tumor diameter was 2.5±1.7 cm. During the mean 51.6 months of follow-up, the local/regional and systemic recurrence rates were 3.7% and 5.2%, respectively; five and 10-year overall survival rates were 86% and 76%.

Conclusion

Despite increasing number of screening centers and free-of-charge mammography (ages 40 to 69) and mobile screening systems in recent years, a significant portion of patients were diagnosed at advanced stage due to lack of breast cancer awareness. In contrast with the study published 5 years ago, there was a decrease in the rate of pre-menopausal women and an increase in the breast conserving surgery.

Use of clinical nomograms for predicting survival outcomes in young women with breast cancer

Early-onset breast cancer (BC) has been recognized to be more aggressive compared with its later counterparts. Survival models of BC in young patients have rarely been reported in previous studies. The current study aimed to establish and validate prediction models with clinicopathological variables for visceral metastasis-free survival (VFS), disease-free-survival (DFS) and overall survival (OS) time in young patients with BC. Clinicopathological data were obtained for 351 patients with primary breast tumors who were ≤40 years old. Univariate and multivariate analyses were performed and nomograms were established to screen and illustrate the prognostic factors. Risk scores were calculated based on coefficients from the Cox regression analysis. Internal validation of the prediction models was conducted by predicting the prognosis of cases randomly sampled from the cohort used in the current study. Multivariate analysis demonstrated that N stage (P=0.004), molecular subtype (P=0.007) and age (P=0.005) were significant independent prognostic factors for VFS. Similarly, N stage (P=0.002) and molecular subtype (P=0.001) were significantly associated with DFS. In addition, N stage (P=0.006), molecular subtype (P=0.006) and the presence of an initially inoperable tumor (P=0.005) were significant independent prognostic factors for OS. According to the Cox regression analysis, nomograms were generated to illustrate the effect of independent prognostic factors on VFS, DFS and OS. Risk scores were calculated and internal validation demonstrated the reliability of the prediction models. In conclusion, N stage and molecular subtype were identified as predictors for VFS, DFS and OS in early-onset BC. Furthermore, an age of <35 years at diagnosis was revealed to be unfavorable for VFS and the presence of an initially inoperable tumor was identified to reduce OS time.

Inverse correlation between Ki67 expression as a continuous variable and outcomes in luminal HER2-negative breast cancer

OBJECTIVES

Few studies to date have investigated the prognostic significance of Ki67 expression as a continuous variable in breast cancer. This study aimed to evaluate the impact of Ki67 expression as a dichotomous or continuous variable on outcomes in estrogen receptor (ER)+ and human epidermal growth factor receptor 2 (HER2)- breast cancer.

METHODS

Survival analysis was performed to estimate the likelihood of distant recurrence and death in retrospective data from 794 patients with ER+/HER2- breast cancer. We assessed the relationship between outcomes and two Ki67 cutoffs, 14% and 20%, and the Ki67 labeling index as a continuous variable.

RESULTS

In univariate analysis, T stage, lymph node involvement, histological grade, progesterone receptor status, and Ki67 expression at the two cutoffs and as a continuous variable were identified as significant prognostic factors for distant disease-free survival (DDFS) and overall survival (OS). There were no statistical differences in DDFS and OS between women with Ki67 expression of <14% and 14-<20%. Multivariate analysis showed that Ki67 expression ≥20% was an independent prognostic indicator for DDFS. Regarding the risk of distant metastasis, the 20% cutoff was more reliable than 14%. We also found that Ki67 expression as a continuous variable was an independent prognostic factor for DDFS and OS in multivariate analyses.

CONCLUSIONS

High Ki67 expression is associated with a survival disadvantage in patients with ER+/HER2- breast cancer, indicating that these patients might have a higher risk of recurrence after primary treatment and might therefore benefit from individualized treatment.

High glucose induces epithelial-mesenchymal transition and results in the migration and invasion of colorectal cancer cells

Diabetes mellitus (DM) is associated with an increased risk of colorectal cancer (CRC). Hyperglycemia, a chronic abnormality in diabetes, is an independent predictor of cancer-associated mortality in CRC. However, the underlying biological mechanism of hyperglycemia in CRC cells is largely unknown. In the present study, HCT-116 and HT-29 cell proliferation, apoptosis, migration and invasion were assessed. In addition, the expression of epithelial (E)-cadherin, vimentin and high-mobility group A protein 2 (HMGA2) were assessed using western blotting. The results demonstrated that high glucose (HG; 30 mmol/l) caused CRC cells to lose their epithelial morphology, with a decrease in E-cadherin and an increase in vimentin, suggesting epithelial-mesenchymal transition (EMT). Furthermore, HG significantly enhanced the cell migration and invasion of CRC cells and the expression of HMGA2. Transfection with HMGA2 small interfering RNA reversed the HG-induced changes to CRC cells. In addition, HG promoted CRC cell proliferation and suppressed apoptosis. The results of the present study suggest that hyperglycemia promotes EMT, proliferation, migration and invasion in CRC cells and may provide novel insights into the link between HG and CRC.

Inverse relationship between Ki67 and survival in early luminal breast cancer: confirmation in a multivariate analysis

INTRODUCTION

Ki67 is a prognostic marker in early breast cancer, but its real usefulness remains controversial. The standard cut-off values for Ki67 have not been universally accepted and different values may be used depending on the type of biopsy (fine needle biopsy versus surgical specimen biopsy). The objective of this study was to evaluate the prognostic significance of Ki67 and to determine the most accurate prognostic cut-off.

MATERIALS AND METHODS

495 tissue samples from patients with luminal tumours who underwent breast surgery between 2005 and 2011 were collected from the Department of Pathology at Hospital de la Santa Creu i Sant Pau, Barcelona. Patients with stage IV, HER2-positive tumours or triple-negative breast carcinoma were excluded from the study. Pathology data including tumour grading and ki67 percentage were obtained retrospectively from clinical records. In all cases, the percentage of ki67 was evaluated in fine needle biopsies.

RESULTS

In the multivariate analysis, Ki67 as a continuous variable was associated with poor overall survival (OS) and cancer-specific survival (CSS) (OS p = 0.0001, HR 1.037, CI 1.014-1.059; CSS p = 0.0001, HR 1.063, CI 1.031-1.096) (Cox regression model). CSS was poor when associated with a KI67 cut-off point >14% (p = 0.013, HR 14.85; CI 1.074-120.53) (Cox regression model). Disease-free survival (DFS) was not associated with Ki67 CONCLUSIONS: Prognosis of luminal breast carcinoma can be predicted using Ki67 as a continuous variable and a standard cut-off value of 14%. Information about the specimen type used to determine ki67 should be recorded in the pathological report.

Comparative study of Her-2, p53, Ki-67 expression and clinicopathological characteristics of breast cancer in a cohort of northern China female patients

The objective was to study the relationship among Her-2, Ki-67, p53 expression and the clinicopathologic characteristics of breast cancer in the patients of northern China. Expression of Her-2, Ki-67, p53 and clinical characteristics of 260 breast cancer patients were retrospectively studied. Her-2 overexpression led to higher incidence rates of infiltrating ductal carcinoma and axillary lymph node metastasis, bigger diameters of the primary tumors, later pTNM staging, and a lower incidence rate of ductal carcinoma in situ (p < 0.05). High expression of ER and PR led to fewer patients classified histologically in higher grade (p = 0.001), while high expression of Ki-67 and p53 caused more patients classified histologically in higher grade (p = 0.001). In patients histologically classified in grade 1 and 2, the expression of Ki-67 and p53 was significantly (p = 0.001) higher, and the expression of ER and PR was significantly lower, in Her-2 positive patients than Her-2 negative patients. Breast cancer with Her-2 overexpression was more likely to recur and metastasize than Her-2 negative breast cancer. Higher coincidence of high expression of p53 and Ki-67 with Her-2 overexpression and more progressed tumors suggested that in addition to p53, Ki-67 might also be a prognostic biomarker of breast cancer.

Triple negative breast cancer chemosensitivity and chemoresistance: current advances in biomarkers indentification

INTRODUCTION

Triple negative breast cancer (TNBC) is a heterogeneous clinicopathological entity constituting approximately 15 - 20% of all breast cancer (BC) patients. It shows high recurrence rate and poor prognosis. At this juncture, because of the lack of specific targeted therapies available and the development in patients of resistance to some therapeutic agents, clinical and translational settings have gained importance over the past decades.

AREAS COVERED

The development of novel, safe and effective alternatives for the treatment of TNBC are in high demand. Therefore, this review aims to summarize the state of the art of TNBC, its current therapies and potential therapeutic targets. In particular, focus is put on recent advances regarding the identification of emerging biomarkers as prognostic and/or predictive markers, including surrogate markers for molecular tumor subtyping and identifying potential responders to new therapies.

EXPERT OPINION

Effective development of informative markers could constitute an important armamentarium tool for identifying appropriate therapies to challenge the aggressiveness of TNBC.

Reduction of global 5-hydroxymethylcytosine is a poor prognostic factor in breast cancer patients, especially for an ER/PR-negative subtype

DNA methylation at the 5 position of cytosine (5 mC) is an epigenetic hallmark in cancer. The 5 mC can be converted to 5-hydroxymethylcytosine (5 hmC) through a ten-eleven-translocation (TET). We investigated the impact of 5 mC, 5 hmC, TET1, and TET2 on tumorigenesis and prognosis of breast cancer. Immunohistochemistry was used to assess the levels of 5 mC, 5 hmC, TET1, and TET2 in the corresponding tumor adjacent normal (n = 309), ductal carcinoma in situ (DCIS, n = 120), and invasive ductal carcinoma (IDC, n = 309) tissues for 309 breast ductal carcinoma patients. 5 mC, 5 hmC, TET1-n, and TET2-n were significantly decreased during DCIS and IDC progression. In IDC, the decrease of 5 hmC was correlated with the cytoplasmic mislocalization of TET1 (p < 0.001) as well as poor disease-specific survival (DSS) (adjusted hazard ratio [AHR] 1.95, p = 0.003) and disease-free survival (DFS) (AHR 1.91, p = 0.006). The combined decrease of 5 mC and 5 hmC was correlated with worse DSS (AHR 2.19, p = 0.008) and DFS (AHR 1.99, p = 0.036). Stratification analysis revealed that the low level of 5 mC was associated with poor DSS (AHR 1.89, p = 0.044) and DFS (AHR 2.02, p = 0.035) for the ER/PR-positive subtype. Conversely, the low level of 5 hmC was associated with worse DSS (AHR 2.77, p = 0.002) and DFS (AHR 2.69, p = 0.006) for the ER/PR-negative subtype. The decreases of 5 mC, 5 hmC, TET1-n, and TET2-n were biomarkers of tumor development. The global reduction of 5 hmC was a poor prognostic factor for IDC, especially for ER/PR-negative subtype.

Exosomes in development, metastasis and drug resistance of breast cancer

Transport through the cell membrane can be divided into active, passive and vesicular types (exosomes). Exosomes are nano-sized vesicles released by a variety of cells. Emerging evidence shows that exosomes play a critical role in cancers. Exosomes mediate communication between stroma and cancer cells through the transfer of nucleic acid and proteins. It is demonstrated that the contents and the quantity of exosomes will change after occurrence of cancers. Over the last decade, growing attention has been paid to the role of exosomes in the development of breast cancer, the most life-threatening cancer in women. Breast cancer could induce salivary glands to secret specific exosomes, which could be used as biomarkers in the diagnosis of early breast cancer. Exosome-delivered nucleic acid and proteins partly facilitate the tumorigenesis, metastasis and resistance of breast cancer. Exosomes could also transmit anti-cancer drugs outside breast cancer cells, therefore leading to drug resistance. However, exosomes are effective tools for transportation of anti-cancer drugs with lower immunogenicity and toxicity. This is a promising way to establish a drug delivery system.