Lack of mismatch repair enhances resistance to methylating agents for cells deficient in oxidative demethylation.

The human AlkB homologs, ALKBH2 and ALKBH3, respond to methylation damage to maintain genomic integrity and cellular viability. Both ALKBH2 and ALKBH3 are direct reversal repair (DRR) enzymes that remove 1meA and 3meC lesions commonly generated by alkylating chemotherapeutic agents. Thus, the existence of deficiencies in ALKBH proteins can be exploited in synergy with chemotherapy. In this study, we investigated possible interactions between ALKBH2 and ALKBH3 with other proteins that could alter damage response and discovered an interaction with the mismatch repair (MMR) system. To test whether the lack of active MMR impacts ALKBH2 and/or ALKBH3 response to methylating agents, we generated cells deficient in ALKBH2, ALKBH3, or both in addition to Mlh homolog 1 (MLH1), another MMR protein. We found that MLH1koALKBH3ko cells showed enhanced resistance towards SN1- and SN2-type methylating agents, whereas MLH1koALKBH2ko cells were only resistant to SN1-type methylating agents. Concomitant loss of ALKBH2 and ALKBH3 (ALKBH2ko3ko) rendered cells sensitive to SN1- and SN2-agents, but the additional loss of MLH1 enhanced resistance to both types of damage. We also showed that ALKBH2ko3ko cells have an ATR-dependent arrest at the G2/M checkpoint, increased apoptotic signalling, and replication fork stress in response to methylation. However, these responses were not observed with the loss of functional MLH1 in MLH1koALKBH2ko3ko cells. Finally, in MLH1koALKBH2ko3ko cells, we observed elevated mutant frequency in untreated and temozolomide treated cells. These results suggest that obtaining a more accurate prognosis of chemotherapeutic outcome requires information on the functionality of ALKBH2, ALKBH3, and MLH1.

Molecular features of luminal breast cancer defined through spatial and single-cell transcriptomics.

BACKGROUND: Intratumour heterogeneity is a hallmark of most solid tumours, including breast cancers. We applied spatial transcriptomics and single-cell RNA-sequencing on patient-derived xenografts (PDXs) to profile spatially resolved cell populations within oestrogen receptor-positive (ER+ ) breast cancer and to elucidate their importance in oestrogen-dependent tumour growth. METHODS: Two PDXs of 'ER-high' breast cancers with opposite oestrogen-mediated growth responses were investigated: oestrogen-suppressed GS3 (80-100% ER) and oestrogen-dependent SC31 (40-90% ER) models. The observation was validated via single-cell analyses on an 'ER-low' PDX, GS1 (5% ER). The results from our spatial and single-cell analyses were further supported by a public ER+ breast cancer single-cell dataset and protein-based dual immunohistochemistry (IHC) of SC31 examining important luminal cancer markers (i.e., ER, progesterone receptor and Ki67). The translational implication of our findings was assessed by clinical outcome analyses on publicly available cohorts. RESULTS: Our space-gene-function study revealed four spatially distinct compartments within ER+ breast cancers. These compartments showed functional diversity (oestrogen-responsive, proliferative, hypoxia-induced and inflammation-related). The 'proliferative' population, rather than the 'oestrogen-responsive' compartment, was crucial for oestrogen-dependent tumour growth, leading to the acquisition of luminal B-like features. The cells expressing typical oestrogen-responsive genes like PGR were not directly linked to oestrogen-dependent proliferation. Dual IHC analyses demonstrated the distinct contribution of the Ki67+ proliferative cells toward oestrogen-mediated growth and their response to a CDK4/6 inhibitor. The gene signatures derived from the proliferative, hypoxia-induced and inflammation-related compartments were significantly correlated with worse clinical outcomes, while patients with the oestrogen-responsive signature showed better prognoses, suggesting that this compartment would not be directly associated with oestrogen-dependent tumour progression. CONCLUSIONS: Our study identified the gene signature in our 'proliferative' compartment as an important determinant of luminal cancer subtypes. This 'proliferative' cell population is a causative feature of luminal B breast cancer, contributing toward its aggressive behaviours.

Benzophenone-3 exposure alters composition of tumor infiltrating immune cells and increases lung seeding of 4T1 breast cancer cells.

Environmental chemicals are a persistent and pervasive part of everyday life. A subset of environmental chemicals are xenoestrogens, compounds that bind to the estrogen receptor (ER) and drive estrogen-related processes. One such chemical, benzophenone-3 (BP3), is a common chemical in sunscreen. It is a potent UV protectant but also is quickly absorbed through the skin. While it has been approved by the FDA, there is a renewed interest in the safety of BP3, particularly in relation to breast cancer. The focus of this study was to examine the impact that BP3 has on triple negative breast cancer (TNBC) through alterations to cells in the immune microenvironment. In this study, we exposed female mice to one of two doses of BP3 before injecting them with a TNBC cell line. Several immune endpoints were examined both in the primary tissues and from in vitro studies of T cell behavior. Our studies revealed that in the lung tumor microenvironment, exposure to BP3 not only increased the number of metastases, but also the total area of tumor coverage. We also found that BP3 caused alterations in immune populations in a tissue-dependent manner, particularly in T cells. Taken together, our data suggest that while BP3 may not directly affect the proliferation of TNBC, growth and metastasis of TNBC-derived tumors can be altered by BP3 exposures via the alterations in the immune populations of the tumor microenvironment.

Castasterone, a Plant Steroid Hormone, Affects Human Small-Cell Lung Cancer Cells and Reverses Multi-Drug Resistance.

Small-cell lung cancer (SCLC) has a dismal prognosis, in part because of the development of multi-drug resistance. Castasterone (CAS) is the metabolic precursor of the plant steroid hormone epibrassinolide (EB). In some plants, EB accounts for the total hormone activity, whereas in other plants, CAS is the active form. The effects of CAS, a BR present in most plants, on animal cells in general and cancer cells in particular have not been described. Here, we report the effects of CAS on drug-sensitive (H69) and drug-resistant (VPA17) SCLC cells. CAS was equally cytotoxic to both cell lines (IC50 = 1 µM), indicating a lack of cross-resistance. Pre-incubation of VPA17 cells with CAS for 96 h reversed drug resistance to etoposide and doxorubicin. Synergism between CAS and EB, as well as with chemotherapy drugs, was investigated by exposure of VPA17 cells to 1:1 ratios of CAS and the other drugs at the respective IC50 values, with dilutions at 0.25 to 2.0 × IC50 and determination of the combination index (CI). CAS and EB were additive, indicating that the two drugs act on the same pathway, whereas CAS-etoposide (CI = 0.77) and CAS-doxorubicin were synergistic, indicating that CAS and the two chemotherapeutic drugs act on different pathways. Apoptosis in SCLC cells was measured by immuno-detection of single-strand DNA breaks. Following 96 h incubation of SCLC H69 cells in CAS, the level of DNA breaks was similar to measurements made after incubation in EB and etoposide, indicating that CAS is pro-apoptotic. Incubation of SCLC cells in CAS led to a time-dependent reduction (by 80%) in the transcriptional activator ß-catenin. These data indicate that CAS may act via Wnt signaling. Taken together, our study reveals that CAS is pharmacologically active in both drug-sensitive and drug-resistant SCLC cells.

Identification and characterization of a proliferative cell population in estrogen receptor-positive metastatic breast cancer through spatial and single-cell transcriptomics.

Background: Intratumor heterogeneity is a hallmark of most solid tumors, including breast cancers. We applied spatial transcriptomics and single-cell RNA-sequencing technologies to profile spatially resolved cell populations within estrogen receptor-positive (ER + ) metastatic breast cancers and elucidate their importance in estrogen-dependent tumor growth. Methods: Spatial transcriptomics and single-cell RNA-sequencing were performed on two patient-derived xenografts (PDXs) of "ER-high" metastatic breast cancers with opposite estrogen-mediated growth responses: estrogen-suppressed GS3 (80-100% ER) and estrogen-stimulated SC31 (30-75% ER) models. The analyses included samples treated with and without 17ß-estradiol. The findings were validated via scRNA-seq analyses on "ER-low" estrogen-accelerating PDX, GS1 (5% ER). The results from our spatial and single-cell analyses were further supported by the analysis of a publicly available single cell dataset and a protein-based dual immunohistochemical (IHC) evaluation using three important clinical markers [i.e., ER, progesterone receptor (PR), and Ki67]. The translational implication of these results was assessed by clinical outcome analyses on public breast cancer cohorts. Results: Our novel space-gene-function study revealed a "proliferative" cell population in addition to three major spatially distinct compartments within ER + metastatic breast cancers. These compartments showed functional diversity (i.e., estrogen-responsive, proliferative, hypoxia-induced, and inflammation-related). The "proliferative ( MKI67 + )" population, not "estrogen-responsive" compartment, was crucial for estrogen-dependent tumor growth, leading to the acquisition of luminal B features. The cells with induction of typical estrogen-responsive genes such as PGR were not directly linked to estrogen-dependent proliferation. Additionally, the dual IHC analyses demonstrated the distinct contribution of the Ki67 + proliferative cells toward estrogen-mediated growth and their response to palbociclib, a CDK4/6 inhibitor. The gene signatures developed from the proliferative, hypoxia-induced, and inflammation-related compartments were significantly correlated with worse clinical outcomes, while patients with the high estrogen-responsive scores showed better prognosis, confirming that the estrogen-responsive compartment would not be directly associated with estrogen-dependent tumor progression. Conclusions: For the first time, our study elucidated a "proliferative" cell population distinctly distributed in ER + metastatic breast cancers. They contribute differently toward progression of these cancers, and the gene signature in the "proliferative" compartment is an important determinant of luminal cancer subtypes.

Mechanism-Driven and Clinically Focused Development of Botanical Foods as Multitarget Anticancer Medicine: Collective Perspectives and Insights from Preclinical Studies, IND Applications and Early-Phase Clinical Trials.

Cancer progression and mortality remain challenging because of current obstacles and limitations in cancer treatment. Continuous efforts are being made to explore complementary and alternative approaches to alleviate the suffering of cancer patients. Epidemiological and nutritional studies have indicated that consuming botanical foods is linked to a lower risk of cancer incidence and/or improved cancer prognosis after diagnosis. From these observations, a variety of preclinical and clinical studies have been carried out to evaluate the potential of botanical food products as anticancer medicines. Unfortunately, many investigations have been poorly designed, and encouraging preclinical results have not been translated into clinical success. Botanical products contain a wide variety of chemicals, making them more difficult to study than traditional drugs. In this review, with the consideration of the regulatory framework of the USFDA, we share our collective experiences and lessons learned from 20 years of defining anticancer foods, focusing on the critical aspects of preclinical studies that are required for an IND application, as well as the checkpoints needed for early-phase clinical trials. We recommend a developmental pipeline that is based on mechanisms and clinical considerations.

Obesity-mediated upregulation of the YAP/IL33 signaling axis promotes aggressiveness and induces an immunosuppressive tumor microenvironment in breast cancer.

Obesity is a well-known risk factor for breast cancer formation and is associated with elevated mortality and a poor prognosis. An obesity-mediated inflammatory microenvironment is conducive to the malignant progression of tumors. However, the detailed molecular mechanism is still needed to be clarified. Herein, we identified that breast cancer cells from mice with diet-induced obesity exhibited increased growth, invasiveness, and stemness capacities. A transcriptome analysis revealed that expressions of interleukin 33 (IL33) signaling pathway-related genes were elevated in obesity-associated breast cancer cells. Importantly, IL33 expression was significantly associated with the yes-associated protein (YAP) signature, and IL33 was transcriptionally regulated by YAP. Suppression of IL33 reduced tumor migration and invasion, while the addition of IL33 activated nuclear factor (NF)-κB signaling and revived tumor mobility in YAP-silenced cells. Furthermore, suppression of YAP attenuated IL33 expression which was accompanied by relief of obesity-mediated immunosuppression. Clinical analyses showed that IL33 expression was markedly associated with macrophage and regulatory T cell infiltration. These findings reveal a crucial role of the YAP/IL33 axis in promoting aggressiveness and immunosuppression of obesity-associated breast cancer progression.

Low-dose exposure to PBDE disrupts genomic integrity and innate immunity in mammary tissue.

The low-dose mixture hypothesis of carcinogenesis proposes that exposure to an environmental chemical that is not individually oncogenic may nonetheless be capable of enabling carcinogenesis when it acts in concert with other factors. A class of ubiquitous environmental chemicals that are hypothesized to potentially function in this low-dose capacity are synthesized polybrominated diphenyl ethers (PBDEs). PBDEs can affect correlates of carcinogenesis that include genomic instability and inflammation. However, the effect of low-dose PBDE exposure on such correlates in mammary tissue has not been examined. In the present study, low-dose long-term (16 weeks) administration of PBDE to mice modulated transcriptomic indicators of genomic integrity and innate immunity in normal mammary tissue. PBDE increased transcriptome signatures for the Nuclear Factor Erythroid 2 Like 2 (NFE2L2) response to oxidative stress and decreased signatures for non-homologous end joining DNA repair (NHEJ). PBDE also decreased transcriptome signatures for the cyclic GMP-AMP Synthase - Stimulator of Interferon Genes (cGAS-STING) response, decreased indication of Interferon Stimulated Gene Factor 3 (ISGF3) and Nuclear Factor Kappa B (NF-κB) transcription factor activity, and increased digital cytometry estimates of immature dendritic cells (DCs) in mammary tissue. Replication of the PBDE exposure protocol in mice susceptible to mammary carcinogenesis resulted in greater tumor development. The results support the notion that ongoing exposure to low levels of PBDE can disrupt facets of genomic integrity and innate immunity in mammary tissue. Such effects affirm that synthesized PBDEs are a class of environmental chemicals that reasonably fit the low-dose mixture hypothesis.

Single-Cell Transcriptomics Identifies Heterogeneity of Mouse Mammary Gland Fibroblasts With Distinct Functions, Estrogen Responses, Differentiation Processes, and Crosstalks With Epithelium.

Fibroblasts have been shown to be one of the essential players for mammary gland organization. Here, we identify two major types of mouse mammary gland fibroblasts through single-cell RNA sequencing analysis: Dpp4 + fibroblasts and Dpp4 - fibroblasts. Each population exhibits unique functional characteristics as well as discrete localization in normal mouse mammary glands. Remarkably, estrogen, a crucial mediator of mammary gland organization, alters the gene expression profiles of fibroblasts in a population-specific manner, without distinct activation of estrogen receptor signaling. Further integrative analysis with the inclusion of five other publicly available datasets reveals a directional differentiation among the mammary gland fibroblast populations. Moreover, the combination with the mouse mammary epithelium atlas allows us to infer multiple potential interactions between epithelial cells and fibroblasts in mammary glands. This study provides a comprehensive view of mouse mammary gland fibroblasts at the single-cell level.

TXNIP Links Anticipatory Unfolded Protein Response to Estrogen Reprogramming Glucose Metabolism in Breast Cancer Cells.

Estrogen and estrogen receptor (ER) play a fundamental role in breast cancer. To support the rapid proliferation of ER+ breast cancer cells, estrogen increases glucose uptake and reprograms glucose metabolism. Meanwhile, estrogen/ER activates the anticipatory unfolded protein response (UPR) preparing cancer cells for the increased protein production required for subsequent cell proliferation. Here, we report that thioredoxin-interacting protein (TXNIP) is an important regulator of glucose metabolism in ER+ breast cancer cells, and estrogen/ER increases glucose uptake and reprograms glucose metabolism via activating anticipatory UPR and subsequently repressing TXNIP expression. In 2 widely used ER+ breast cancer cell lines, MCF7 and T47D, we showed that MCF7 cells express high TXNIP levels and exhibit mitochondrial oxidative phosphorylation (OXPHOS) phenotype, while T47D cells express low TXNIP levels and display aerobic glycolysis (Warburg effect) phenotype. Knockdown of TXNIP promoted glucose uptake and Warburg effect, while forced overexpression of TXNIP inhibited glucose uptake and Warburg effect. We further showed that estrogen represses TXNIP expression and activates UPR sensor inositol-requiring enzyme 1 (IRE1) via ER in the breast cancer cells, and IRE1 activity is required for estrogen suppression of TXNIP expression and estrogen-induced cell proliferation. Our study suggests that TXNIP is involved in estrogen-induced glucose uptake and metabolic reprogramming in ER+ breast cancer cells and links anticipatory UPR to estrogen reprogramming glucose metabolism.

Influence of Estrogen Treatment on ESR1+ and ESR1- Cells in ER+ Breast Cancer: Insights from Single-Cell Analysis of Patient-Derived Xenograft Models.

A 100% ER positivity is not required for an endocrine therapy response. Furthermore, while estrogen typically promotes the progression of hormone-dependent breast cancer via the activation of estrogen receptor (ER)-α, estrogen-induced tumor suppression in ER+ breast cancer has been clinically observed. With the success in establishing estrogen-stimulated (SC31) and estrogen-suppressed (GS3) patient-derived xenograft (PDX) models, single-cell RNA sequencing analysis was performed to determine the impact of estrogen on ESR1+ and ESR1- tumor cells. We found that 17ß-estradiol (E2)-induced suppression of GS3 transpired through wild-type and unamplified ERα. E2 upregulated the expression of estrogen-dependent genes in both SC31 and GS3; however, E2 induced cell cycle advance in SC31, while it resulted in cell cycle arrest in GS3. Importantly, these gene expression changes occurred in both ESR1+ and ESR1- cells within the same breast tumors, demonstrating for the first time a differential effect of estrogen on ESR1- cells. E2 also upregulated a tumor-suppressor gene, IL-24, in GS3. The apoptosis gene set was upregulated and the G2M checkpoint gene set was downregulated in most IL-24+ cells after E2 treatment. In summary, estrogen affected pathologically defined ER+ tumors differently, influencing both ESR1+ and ESR1- cells. Our results also suggest IL-24 to be a potential marker of estrogen-suppressed tumors.

Mitochondrial stress adaptation promotes resistance to aromatase inhibitor in human breast cancer cells via ROS/calcium up-regulated amphiregulin-estrogen receptor loop signaling.

Many breast cancer patients harbor high estrogen receptor (ER) expression in tumors that can be treated with endocrine therapy, which includes aromatase inhibitors (AI); unfortunately, resistance often occurs. Mitochondrial dysfunction has been thought to contribute to progression and to be related to hormone receptor expression in breast tumors. Mitochondrial alterations in AI-resistant breast cancer have not yet been defined. In this study, we characterized mitochondrial alterations and their roles in AI resistance. MCF-7aro AI-resistant breast cancer cells were shown to have significant changes in mitochondria. Low expressions of mitochondrial genes and proteins could be poor prognostic factors for breast cancer patients. Long-term mitochondrial inhibitor treatments-mediated mitochondrial stress adaptation could induce letrozole resistance. ERα-amphiregulin (AREG) loop signaling was activated and contributed to mitochondrial stress adaptation-mediated letrozole resistance. The up-regulation of AREG-epidermal growth factor receptor (EGFR) crosstalk activated the PI3K/Akt/mTOR and ERK pathways and was responsible for ERα activation. Moreover, mitochondrial stress adaptation-increased intracellular levels of reactive oxygen species (ROS) and calcium were shown to induce AREG expression and secretion. In conclusion, our results support the claim that mitochondrial stress adaptation contributes to AI resistance via ROS/calcium-mediated AREG-ERα loop signaling and provide possible treatment targets for overcoming AI resistance.

Effects of PI3K inhibition in AI-resistant breast cancer cell lines: autophagy, apoptosis, and cell cycle progression.

INTRODUCTION: Breast cancer is the leading cause of cancer death in women. The aromatase inhibitors (AIs), Anastrozole (Ana), Letrozole (Let), and Exemestane (Exe) are a first-line treatment option for estrogen receptor-positive (ER+) breast tumors, in postmenopausal women. Nevertheless, the development of acquired resistance to this therapy is a major drawback. The involvement of PI3K in resistance, through activation of the PI3K/AKT/mTOR survival pathway or through a cytoprotective autophagic process, is widely described. MATERIALS AND METHODS: The involvement of autophagy in response to Ana and Let treatments and the effects of the combination of BYL-719, a PI3K inhibitor, with AIs were explored in AI-resistant breast cancer cell lines (LTEDaro, AnaR, LetR, and ExeR). RESULTS: We demonstrate that Ana and Let treatments do not promote autophagy in resistant breast cancer cells, contrary to Exe. Moreover, the combinations of BYL-719 with AIs decrease cell viability by different mechanisms by nonsteroidal vs. steroidal AIs. The combination of BYL-719 with Ana or Let induced cell cycle arrest while the combination with Exe promoted cell cycle arrest and apoptosis. In addition, BYL-719 decreased AnaR, LetR, and ExeR cell viability in a dose- and time-dependent manner, being more effective in the ExeR cell line. This decrease was further exacerbated by ICI 182,780. CONCLUSION: These results corroborate the lack of cross-resistance between AIs verified in the clinic, excluding autophagy as a mechanism of resistance to Ana or Let and supporting the ongoing clinical trials combining BYL-719 with AIs.

White button mushroom interrupts tissue AR-mediated TMPRSS2 expression and attenuates pro-inflammatory cytokines in C57BL/6 mice.

White button mushroom (WBM) is a common edible mushroom consumed in the United States and many European and Asia-Pacific countries. We previously reported that dietary WBM antagonized dihydrotestosterone (DHT)-induced androgen receptor (AR) activation and reduced myeloid-derived suppressor cells (MDSCs) in prostate cancer animal models and patients. Transmembrane protease serine 2 (TMPRSS2), an androgen-induced protease in prostate cancer, has been implicated in influenza and coronavirus entry into the host cell, triggering host immune response. The present study on C57BL/6 mice revealed that WBM is a unique functional food that (A) interrupts AR-mediated TMPRSS2 expression in prostate, lungs, small intestine, and kidneys through its AR antagonistic activity and (B) attenuates serum pro-inflammatory cytokines and reduces MDSC counts through its immunoregulatory activity. These findings provide a scientific basis for translational studies toward clinical applications of WBM in diseases related to TMPRSS2 expression and immune dysregulation.

Methylation biomarkers of polybrominated diphenyl ethers (PBDEs) and association with breast cancer risk at the time of menopause.

BACKGROUND: Exposure to polybrominated diphenyl ethers (PBDEs) may influence risk of developing post-menopausal breast cancer. Although mechanisms are poorly understood, epigenetic regulation of gene expression may play a role. OBJECTIVES: To identify DNA methylation (DNAm) changes associated with PBDE serum levels and test the association of these biomarkers with breast cancer risk. METHODS: We studied 397 healthy women (controls) and 133 women diagnosed with breast cancer (cases) between ages 40 and 58 years who participated in the California Teachers Study. PBDE levels were measured in blood. Infinium Human Methylation EPIC Bead Chips were used to measure DNAm. Using multivariable linear regression models, differentially methylated CpG sites (DMSs) and regions (DMRs) associated with serum PBDE levels were identified using controls. For top-ranked DMSs and DMRs, targeted next-generation bisulfite sequencing was used to measure DNAm for 133 invasive breast cancer cases and 301 age-matched controls. Conditional logistic regression was used to evaluate associations between DMSs and DMRs and breast cancer risk. RESULTS: We identified 15 DMSs and 10 DMRs statistically significantly associated with PBDE levels (FDR < 0.05). Methylation changes in a DMS at BMP8B and DMRs at TP53 and A2M-AS1 were statistically significantly (FDR < 0.05) associated with breast cancer risk. CONCLUSION: We show for the first time that serum PBDE levels are associated with differential methylation and that PBDE-associated DNAm changes in blood are associated with breast cancer risk.

Exploring the Biological Activity and Mechanism of Xenoestrogens and Phytoestrogens in Cancers: Emerging Methods and Concepts.

Xenoestrogens and phytoestrogens are referred to as "foreign estrogens" that are produced outside of the human body and have been shown to exert estrogen-like activity. Xenoestrogens are synthetic industrial chemicals, whereas phytoestrogens are chemicals present in the plant. Considering that these environmental estrogen mimics potentially promote hormone-related cancers, an understanding of how they interact with estrogenic pathways in human cells is crucial to resolve their possible impacts in cancer. Here, we conducted an extensive literature evaluation on the origins of these chemicals, emerging research techniques, updated molecular mechanisms, and ongoing clinical studies of estrogen mimics in human cancers. In this review, we describe new applications of patient-derived xenograft (PDX) models and single-cell RNA sequencing (scRNA-seq) techniques in shaping the current knowledge. At the molecular and cellular levels, we provide comprehensive and up-to-date insights into the mechanism of xenoestrogens and phytoestrogens in modulating the hallmarks of cancer. At the systemic level, we bring the emerging concept of window of susceptibility (WOS) into focus. WOS is the critical timing during the female lifespan that includes the prenatal, pubertal, pregnancy, and menopausal transition periods, during which the mammary glands are more sensitive to environmental exposures. Lastly, we reviewed 18 clinical trials on the application of phytoestrogens in the prevention or treatment of different cancers, conducted from 2002 to the present, and provide evidence-based perspectives on the clinical applications of phytoestrogens in cancers. Further research with carefully thought-through concepts and advanced methods on environmental estrogens will help to improve understanding for the identification of environmental influences, as well as provide novel mechanisms to guide the development of prevention and therapeutic approaches for human cancers.