Breast cancer and its therapeutic targets: A comprehensive review

Breast cancer is a common and deadly disease, so there is a constant need for research to find efficient targets and therapeutic approaches. Breast cancer can be classified on a molecular and histological base. Breast cancer can be divided into ER (estrogen receptor)-positive and ER-negative, HER2 (human epidermal growth factor receptor2)-positive and HER2-negative subtypes based on the presence of specific biomarkers. Targeting hormone receptors, such as the HER2, progesterone receptor (PR), and ER, is very significant and plays a vital role in the onset and progression of breast cancer. Endocrine treatments and HER2-targeted drugs are examples of targeted therapies now being used against these receptors. Emerging immune-based medicines with promising outcomes in the treatment of breast cancer include immune checkpoint inhibitors, cancer vaccines, and adoptive T-cell therapy. It is also explored how immune cells and the tumor microenvironment affect breast cancer development and treatment response. The major biochemical pathways, signaling cascades, and DNA repair mechanisms that are involved in the development and progression of breast cancer, include the PI3K/AKT/mTOR system, the MAPK pathway, and others. These pathways are intended to be inhibited by a variety of targeted drugs, which are then delivered with the goal of restoring normal cellular function. This review aims to shed light on types of breast cancer with the summarization of different therapeutic approaches which can target different pathways for tailored medicines and better patient outcomes.

Naringenin stimulates aromatase expression and alleviates the clinical and histopathological findings of experimental autoimmune encephalomyelitis in C57bl6 mice

This study was conducted to demonstrate the possible protective and therapeutic effects of naringenin, an estrogenically effective flavonoid, in experimental autoimmune encephalomyelitis (EAE), which is the rodent model of multiple sclerosis. For this purpose, 50 12-week-old C57BL6 male mice were divided into five groups; control, naringenin, EAE, prophylactic naringenin + EAE, and EAE + therapeutic naringenin. The EAE model was induced with myelin oligodendrocyte glycoprotein(35-55), and naringenin (50 mg/kg) was administered by oral gavage. The prophylactic and therapeutic effects of naringenin were examined according to clinical, histopathological, immunohistochemical, electron microscopic, and RT-PCR (aromatase, 3βHSD, estrogen receptors, and progesterone receptor expression) parameters. The acute EAE model was successfully induced, along with its clinical and histopathological findings. RT-PCR showed that expression of aromatase, 3βHSD, estrogen receptor-β, and progesterone receptor gene decreased, while estrogen receptor-α increased after EAE induction. Electron microscopic analysis showed mitochondrial damage and degenerative changes in myelinated axons and neurons in EAE, which could be behind the downregulation in the expressions of neurosteroid enzymes. Aromatase immunopositivity rates also decreased in EAE, while estrogen receptor α and β, and progesterone receptor immunopositivity rates increased. Naringenin improved aromatase immunopositivity rates and gene expression in both prophylactic and therapeutic use. Clinical and histopathological findings revealed that EAE findings were alleviated in both prophylactic and therapeutic groups, along with significantly decreased inflammatory cell infiltrations in the white matter of the spinal cords. In conclusion, naringenin could provide long-term beneficial effects even in prophylactic use due to stimulating aromatase expression, but it could not prevent or eliminate the EAE model's lesions completely.

Molecular classification of hormone receptor-positive HER2-negative breast cancer

Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer is the most prevalent type of breast cancer, in which endocrine therapy resistance and distant relapse remain unmet challenges. Accurate molecular classification is urgently required for guiding precision treatment. We established a large-scale multi-omics cohort of 579 patients with HR+/HER2- breast cancer and identified the following four molecular subtypes: canonical luminal, immunogenic, proliferative and receptor tyrosine kinase (RTK)-driven. Tumors of these four subtypes showed distinct biological and clinical features, suggesting subtype-specific therapeutic strategies. The RTK-driven subtype was characterized by the activation of the RTK pathways and associated with poor outcomes. The immunogenic subtype had enriched immune cells and could benefit from immune checkpoint therapy. In addition, we developed convolutional neural network models to discriminate these subtypes based on digital pathology for potential clinical translation. The molecular classification provides insights into molecular heterogeneity and highlights the potential for precision treatment of HR+/HER2- breast cancer.

Complete pathological response in patients with HER2 positive breast cancer treated with neoadjuvant therapy in Colombia

Introduction

Breast cancer is the most common type of cancer and the leading cause of death by cancer in women in Colombia. Approximately 15 to 20% of breast cancers overexpress HER2.

Objective

To analyze the relationship between multiple clinical and histological variables and pathological complete response in patients with HER2-positive breast cancer undergoing neoadjuvant therapy in a specialized cancer center in Colombia.

Materials and methods

We performed a retrospective analysis of non-metastatic HER2-positive breast cancer patients who received neoadjuvant therapy between 2007 and 2020 at the Instituto de Cancerología Las Americas Auna (Medellín, Colombia). Assessed parameters were tumor grade, proliferation index, estrogen receptor, progesterone receptor, HER2 status, type of neoadjuvant therapy, pathologic complete response rates, and overall survival.

Results

Variables associated with low pathologic complete response rates were tumor grades 1-2 (OR = 0.55; 95% CI = 0.37-0.81; p = 0.03), estrogen receptor positivity (OR =0.65; 95%; CI = 0.43-0.97; p=0.04), and progesterone receptor positivity (OR = 0.44; 95% CI = 0.29-0.65; p = 0.0001). HER2 strong positivity (score 3+) was associated with high pathological complete response rates (OR = 3.3; 95% CI = 1.3-8.35; p=0.013). Five-year overall survival was 91.5% (95% CI = 82.6-95.9) in patients with pathological complete response and 73.6% (95% CI = 66.4-79.6) in patients who did not achieve pathological complete response (p = 0.001). Additionally, the pathological complete response rate was three times higher in patients receiving combined neoadjuvant chemotherapy with anti-HER2 therapy than in those with chemotherapy alone (48% versus 16%).

Conclusions

In patients with HER2-positive breast cancer, tumor grade 3, estrogen receptor negativity, progesterone receptor negativity, strong HER2 positivity (score 3+), and the use of the neoadjuvant trastuzumab are associated with higher pathological complete response rates.

Systemic therapy for hormone receptor-positive/human epidermal growth factor receptor 2-negative early stage and metastatic breast cancer

Hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is defined by the presence of the estrogen receptor and/or the progesterone receptor and the absence of HER2 gene amplification. HR-positive/HER2-negative breast cancer accounts for 65%-70% of all breast cancers, and incidence increases with increasing age. Treatment varies by stage, and endocrine therapy is the mainstay of treatment in both early stage and late-stage disease. Combinations with cyclin-dependent kinase 4/6 inhibitors have reduced distant recurrence in the early stage setting and improved overall survival in the metastatic setting. Chemotherapy is used based on stage and tumor biology in the early stage setting and after endocrine resistance for advanced disease. New therapies, including novel endocrine agents and antibody-drug conjugates, are now changing the treatment landscape. With the availability of new treatment options, it is important to define the optimal sequence of treatment to maximize clinical benefit while minimizing toxicity. In this review, the authors first discuss the pathologic and molecular features of HR-positive/HER2-negative breast cancer and mechanisms of endocrine resistance. Then, they discuss current and emerging therapies for both early stage and metastatic HR-positive/HER2-negative breast cancer, including treatment algorithms based on current data.

Breast Cancer Recurrence by Subtype in a Diverse, Contemporary Cohort of Young Women

BACKGROUND

Young breast cancer (YBC) patients are a unique subpopulation that are often underrepresented in randomized clinical trials. Furthermore, large national cancer databases lack detailed information on recurrence, a meaningful oncologic outcome for young patients.

STUDY DESIGN

A retrospective review of YBC patients (age 40 years or younger) with stage I to III breast cancer diagnosed from 2008 to 2018 was performed. Information on clinicopathologic characteristics, demographics, and outcomes was obtained from the electronic health record and chart review. Chi-square and Fisher's exact tests were used for comparisons of categorical variables and parametric and nonparametric tests for continuous variables.

RESULTS

The cohort included 1,431 women with a median follow-up of 4.8 years (range 0.3 to 12.9 years). The median age was 37 years (interquartile range 34 to 39). The study population included 598 (41.8%) White, 112 (7.8%) Black, 420 (29.4%) Asian/Pacific Islander, 281 (19.6%) Hispanic, and 20 (1.4%) "other" race/ethnicity patients. Tumor subtype was as follows: [1] hormone receptor (HR) + /human epidermal growth factor 2 (HER2 - ), grade (G) 1 to 2 = 541 (37.8%); [2] HR + /HER2 - , G3 = 268 (18.7%); [3] HR + /HER2 + = 262 (18.3%); [4] HR - /HER2 + = 101 (7.1%); [5] HR - /HER2 - = 259 (18.1%). The majority (64.2%) presented with stage II/III disease. There were 230 (16.1%) recurrences during follow-up; 74.8% were distant. Locoregional-only recurrence was seen in 17 of 463 (3.7%) patients who underwent breast conservation vs 41 of 968 (4.2%) patients undergoing mastectomy (p < 0.001). Recurrence varied by tumor subtype: [1] HR + /HER2 - , G1 to 2 (14.0%); [2] HR + /HER2 - , G3 (20.9%); [3] HR + /HER2 + (11.1%); [4] HR - /HER2 + (22.8%); [5] HR - /HER2 - (17.8%) (p = 0.005).

CONCLUSIONS

In this large, diverse YBC cohort, recurrences were most frequent among HR + /HER2 - , G3, or HR - /HER2 + invasive tumors; most were distant. There were numerically similar locoregional-only recurrences after breast conservation vs mastectomy. Additional research is needed to identify predictors of recurrence.

The role of progesterone and the progesterone receptor in cancer: progress in the last 5 years

INTRODUCTION

Patients with various advanced cancers devoid of nuclear progesterone receptors (nPR) have demonstrated increased quality and length of life when treated with the PR modulator mifepristone, which likely works by interacting with membrane PRs (mPR).

AREAS COVERED

Two immunomodulatory proteins are discussed that seem to play a role in cancers that proliferate whether the malignant tumor is positive or negative for the nPR. These two proteins are the progesterone receptor membrane component-1 (PGRMC-1) and the progesterone-induced blocking factor (PIBF). Both PGRMC-1 and the parent form of PIBF foster increased tumor aggressiveness, whereas splice variants of the 90 kDa form of PIBF inhibit immune response against cancer cells.

EXPERT OPINION

The marked clinical improvement following 200-300 mg of mifepristone is likely related to blocking PIBF. In the low dosage used, mifepristone likely acts as an agonist for PGRMC-1 protein. Mifepristone may be less effective for cancers positive for the nPR because the nPR may be protective and blocking it may have detrimental effects. Based on this hypothetical model, the development of other potential treatment options to provide even greater efficacy for treating cancer are discussed.

Glucocorticoid receptor blockers

Mifepristone is the only glucocorticoid receptor antagonist currently approved for the treatment of Cushing's syndrome. Although originally developed as an abortifacient due to its blockade of the progesterone receptor, a number of case reports documented its efficacy as a glucocorticoid receptor blocker going back to 1985. The SEISMIC trial, published in 2012, provided sufficient data on efficacy and adverse effects for regulatory approval. Mifepristone provides clear benefits on glycemia, blood pressure, muscle weakness, body weight and the other myriad clinical manifestations of Cushing's syndrome. However, because it blocks the glucocorticoid receptor, blood cortisol and ACTH levels actually rise, rather than fall; this complicates patient management. Doses are adjusted based on clinical manifestations rather than hormone levels. Adverse effects include adrenal insufficiency due to overdosage, hypokalemia, and menorrhagia. Treatment of severe adrenal insufficiency requires high doses of dexamethasone. Other glucocorticoid receptor blockers without effects on the progesterone receptor are being developed. Because mifepristone inhibits CYP3A and CYP2C8/2C9, drug-drug interactions can occur. These potential adverse effects can largely be avoided with careful attention to detail. My opinion is that its current place in therapy is in patients with severe disease and in those not responding to other treatments.

The relationship of patients, giving or not giving a pathological full response, wıth YAP (Yes Associated Protein) in breast cancer cases to which neo-adjuvant chemotherapy is applied

AIM

We aimed to evaluate (immunohistochemically) the YAP expression in breast cancer patients undergoing neoadjuvant chemotherapy and to clarify the relationship between the molecular characteristics, treatment response and survival data and the YAP expression, and hence, to clarify the prognostic significance.

MATERIAL AND METHODS

One hundred and four patients who were diagnosed with Breast Cancer between 2015-2020 and underwent Neo Adjuvant Chemotherapy were included in the study. Estrogen Receptor(ER), Progesterone Receptor(PR), Human Epidermal Growth Receptor-2(HER2) and Ki-67. Expression are routinely stained immunohistochemically. In this study, existing immunohistochemical markers were reviewed and also, the relationship of YAP with these biological markers was evaluated by using immunohistochemistry and its effect on prognosis has been investigated.

RESULTS

The average age of the patients was 52.37. While YAP was positive in 78 patients (75%), it was negative in 26 patients (25%). In the evaluation after neoadjuvant therapy, pathological complete response (MillerPayne Grade5 response) in 28 patients (26.9%), relapse in 6 patients (5.8%), and exitus in 6 patients (5.8%) were detected. In the pathological evaluation, invasive Ductal Carcinoma was the most common one observed in 88 patients (84.6%). As a result of the statistical evaluation, no significant result was obtained between the parameters and YAP negative/positive.

CONCLUSION

As a result of staining with additional YAP in patients who were diagnosed with breast cancer and routinely stained with ER, PR, Cerb B2 and Ki-67 in pathology samples, we could not reach a result that would contribute positively to survival. Longer studies to be conducted prospectively will be meaningful.

KEY WORDS

Breast Cancer, Chemotherapy, Neoadjuvant, Yes Associated Protein.

Neoadjuvant chemotherapy in hormone receptor-positive/HER2-negative early breast cancer: When, why and what?

Indication for neoadjuvant chemotherapy (NACT) in HR+/HER2-negative tumors is controversial. Pathological complete response (pCR) rates range from 0 to 18 % while breast-conserving surgery (BCS) is achievable in up to 60 % of tumors. No pathological feature definitely predicts pCR; lobular and molecular luminal A tumors are less likely to achieve pCR although experiencing better outcomes. Luminal B subtype, high proliferation, lack of progesterone receptor, high tumor-infiltrating lymphocytes are positively associated with increased pCR rates but worse outcomes and the prognostic role of pCR is inconsistent across studies. Molecular intrinsic subtyping and genomic signatures appear as more accurate predictors of benefit from NACT, but larger studies are needed. Anthracycline and taxane-based chemotherapy remains the standard NACT; however, CDK 4/6 inhibitors and immune checkpoint inhibitors are under evaluation. In conclusion, NACT may be proposed for luminal tumors requiring downsizing for BCS after multidisciplinary evaluation, provided that other contraindications to BCS are excluded.

Estrogen Receptor Positive and Progesterone Receptor Negative Breast Cancer: the Role of Hormone Therapy

ER+/PR- (estrogen receptor positive and progesterone receptor negative) tumors constitute only a small portion of the breast cancer population. Patients with ER+/PR- tumors, however, are characterized by worse survival compared to patients with ER+/PR+ (estrogen receptor positive and progesterone receptor positive) tumors. Controversy exists regarding the efficacy of hormone blocking therapy for patients with ER+/PR- tumors. The NCDB was queried between 2004 and 2015, and patients with invasive ER+/PR- tumors were identified. We employed univariate Cox proportional hazards to compare outcomes among patients that did or did not receive hormone blocking therapy. We identified 138,398 patients with invasive ER+/PR- tumors, 32,044 (23%) of whom did not receive hormone blocking therapy. The reasons for not receiving hormone blocking therapy included contraindications to treatment, death, patient refusal, and unknown. There were no significant differences in race, income quartile, or education quartile between patients who did and did not receive hormone blocking therapy. Patients who did not receive hormone blocking therapy underwent surgical assessment of the axilla more frequently than those who did receive hormone therapy. Our analysis demonstrated that hormone blocking therapy administration was associated with increased overall survival for up to 10 years of follow up (HR: 0.58; 95% CI: 0.56-0.59, p < 0.001). Hormone blocking therapy may be associated with increased survival for breast cancer patients with ER+/PR- tumors. Although this benefit may last for years after completion of the course, up to 25% of patients do not receive this treatment. Strategies to increase the utilization and adherence to hormone blocking therapy regimens may improve patient survival outcomes.

Menorrhagia, mechanisms and targeted therapies

PURPOSE OF REVIEW

Efficient treatment options for the increasing complaint of heavy menstrual bleeding are required to avoid the morbidity associated with major surgery. This review summarizes recent developments in the nonsurgical approach to treating menorrhagia.

RECENT FINDINGS

Even though the mechanism of menstruation has still not been fully elucidated, there have been promising developments in the attempt to reduce menstrual blood loss. The levonorgestrel-releasing intrauterine system has proven very efficient, and there is a frameless device suitable for enlarged uterine cavities. The side effect of breakthrough bleeding has been the main reason for discontinuing treatment. Recent studies have investigated options of concomitant therapy with antiprogestogens to counter this effect. Another group of novel compounds are selective progesterone receptor modulators, which thus far have been shown to reduce menstrual bleeding without the unwanted effect of unscheduled bleeding episodes.

SUMMARY

As menorrhagia is largely a subjective complaint, it is important for successful therapy to be based on an informed patient's choice. Currently, lack of evidence-based practice, poor compliance and unpleasant side effects limit the success of medical therapies contributing to the amount of major surgery performed for this indication. If concomitant therapies succeeded in minimizing the episodes of breakthrough bleeding with the levonorgestrel-releasing intrauterine system, its recommendation as a first choice treatment may be confounded. Further research is needed into efficiency and safety of selective progesterone receptor modulators, which appear to have great potential in reducing menstrual blood loss.

Progesterone receptor activation. an alternative to SERMs in breast cancer

Data regarding the effects of progesterone and a progestagen on human normal breast epithelial cell proliferation and apoptosis are presented here. In postmenopausal women, adding progesterone to percutaneously administrated oestradiol significantly reduces the proliferation induced by oestradiol. In vitro and in premenopausal women, stopping the administration of nomegestrol acetate triggers a peak of apoptosis. Fibro-adenoma and cancerous cells do not show this regulation of apoptosis. Progesterone seems to be important in normal breast homeostasis.