Barriers in Latin America for the management of locally advanced breast cancer

Validation of the Mirai model for predicting breast cancer risk in Mexican women

OBJECTIVES

To validate the performance of Mirai, a mammography-based deep learning model, in predicting breast cancer risk over a 1-5-year period in Mexican women.

METHODS

This retrospective single-center study included mammograms in Mexican women who underwent screening mammography between January 2014 and December 2016. For women with consecutive mammograms during the study period, only the initial mammogram was included. Pathology and imaging follow-up served as the reference standard. Model performance in the entire dataset was evaluated, including the concordance index (C-Index) and area under the receiver operating characteristic curve (AUC). Mirai's performance in terms of AUC was also evaluated between mammography systems (Hologic versus IMS). Clinical utility was evaluated by determining a cutoff point for Mirai's continuous risk index based on identifying the top 10% of patients in the high-risk category.

RESULTS

Of 3110 patients (median age 52.6 years ± 8.9), throughout the 5-year follow-up period, 3034 patients remained cancer-free, while 76 patients developed breast cancer. Mirai achieved a C-index of 0.63 (95% CI: 0.6-0.7) for the entire dataset. Mirai achieved a higher mean C-index in the Hologic subgroup (0.63 [95% CI: 0.5-0.7]) versus the IMS subgroup (0.55 [95% CI: 0.4-0.7]). With a Mirai index score > 0.029 (10% threshold) to identify high-risk individuals, the study revealed that individuals in the high-risk group had nearly three times the risk of developing breast cancer compared to those in the low-risk group.

CONCLUSIONS

Mirai has a moderate performance in predicting future breast cancer among Mexican women.

CRITICAL RELEVANCE STATEMENT

Prospective efforts should refine and apply the Mirai model, especially to minority populations and women aged between 30 and 40 years who are currently not targeted for routine screening.

KEY POINTS

The applicability of AI models to non-White, minority populations remains understudied. The Mirai model is linked to future cancer events in Mexican women. Further research is needed to enhance model performance and establish usage guidelines.

Core needle biopsy of breast tumours: comparison of diagnostic performance between surgery and radiology services at a national cancer centre in Latin America

Introduction

Breast pathology is a very common reason for medical attention. Tissue diagnosis is usually obtained with core needle biopsy which could be performed by breast surgeons or interventional radiologists. Our aim was to assess the comparison of diagnostic performance between the two services.

Methods

A retrospective, descriptive and cross-sectional study was carried out on patients who had breast pathology at Instituto Nacional de Enfermedades Neoplasicas in 2019. Descriptive analyses, sensitivity and specificity were calculated using the R program version 4.2.3.

Results

From 1,082 patients with breast tumours who underwent core needle biopsy (CNB) during 2019, 782 cases were included. Breast surgeons performed 462 CNBs and radiologists performed 320 CNBs. The 87.5% were palpable tumours and 525 breast carcinomas were identified in the final pathology. The diagnostic performance showed that the sensitivity and specificity were greater than 95% and 98%, respectively. The waiting time in both showed that >95% underwent a CNB before 2 months. The breast surgery service performed the majority of the biopsies in less than 1 week since the indication of the execution of the CNB compared to the radiology service (90% versus 36%).

Conclusion

Both hospital services, breast surgery and radiology, are efficient in determining an accurate diagnosis using CNB. However, the breast surgery service performs CNB in a shorter time interval. Breast surgical oncologists are encouraged to perform CNB if there are understaffed radiology services to expedite the diagnosis and treatment of breast cancer patients.

Impact of the COVID-19 Pandemic on the Treatment of Cancer Patients at a Hospital in Peru

BACKGROUND

The appearance of the new coronavirus, SARS-CoV-2, in Wuhan - China, in 2019 led to the declaration of a COVID-19 pandemic by the World Health Organization. Peru confirmed its first case on March 6, 2020, prompting a significant change in medical care.

PURPOSE

Our objective was to determine the impact of the COVID-19 pandemic on cancer treatment in Peru.

METHODS

A retrospective analysis of hospital data from the National Institute of Neoplastic Diseases revealed substantial decreases in oncological treatments in 2020 compared to 2019.

RESULTS

Oncological treatments involving bone marrow transplantation had a greater impact between the months of April and September, at -100% (p=0.003). However, treatments involving surgery in April (-95% [p≤0.001]), radiotherapy in May (-76% [p=0.002]) and chemotherapy in June (-71% [p≤0.001]) also showed significant impacts. Comparative analysis with international data revealed similar trends in cancer care interruptions in different countries. However, variations in the magnitude of the impact were observed, influenced by regional health policies and the severity of the pandemic.

CONCLUSIONS

The findings underscore the challenges cancer care providers face during public health crises, requiring adaptive strategies to ensure continued access to essential treatments. Addressing these challenges requires comprehensive public health responses to mitigate the impact of future crises on cancer care systems.

Suboptimal use of ovarian function suppression in very young women with early breast cancer: a real-world data study

PURPOSE

The incidence of breast cancer in young women (BCYW) has increased in recent decades. Malignant disease in this subset is characterized by its aggressiveness and poor prognosis. Ovarian function suppression (OFS) in these patients improves survival especially in hormone receptor-positive (HR +) cases. The Regan Composite Risk (RCR) is a prognostic tool to identify high-risk HR + BC candidates for OFS. Our study sought to characterize a Chilean cohort of early HR + BCYW assessing the use of OFS and its related prognosis and the utility of RCR in our patients.

METHODS

This was a retrospective population cohort study that included ≤ 35-year-old early HR + /human epidermal growth factor receptor 2 -negative (HER2-) BC patients treated between 2001 and 2021. Analysis included clinical-pathological characteristics, treatment strategies, and survival. Also, we evaluated the association between RCR and survival.

RESULTS

A total of 143 patients were included into our study, representing 2.9% of all early BC cases in our registry. Median age was 31 years old (range: 19-35). Most patients (93%) received endocrine therapy (ET). Of these, 18% received OFS. No survival differences were observed among treatment strategies. Median RCR score for patients treated with CT plus ET was significantly higher vs. ET alone (2.95 vs. 1.91; p = 0.0001). Conversely, patients treated with tamoxifen alone had significantly lower RCR scores vs. OFS (2.72 vs. 3.14; p = 0.04). Higher RCR scores were associated with poorer overall survival.

CONCLUSION

Less than 20% of very young women with early HR + /HER2-BC in our cohort received OFS, in most cases, this involved surgical oophorectomy. RCR score was higher in patients that underwent CT and OFS and was associated with survival, regardless of treatment. We confirm the RCR score as a valuable prognostic tool to identify high-risk BC patients who could benefit from OFS.

Real-world data on triple-negative breast cancer in Latin America and the Caribbean

Breast cancer (BC) is the most prevalent cancer in women in Latin America and the Caribbean. We compiled real-world data (RWD) on the epidemiology, diagnosis, treatment, and patient outcomes of triple-negative breast cancer (TNBC), addressing the main barriers to optimal care in Latin America. The prevalence of TNBC varies between 11% and 38.5% of all BC cases diagnosed in the region, and TNBC primarily affects young patients. Delays in BC diagnosis, with consequent advanced disease stages and barriers to access efficient therapies, particularly due to high costs, negatively impact patient outcomes. Cancer clinical trials are an opportunity to access standard and novel therapies for patients with this aggressive BC subtype and thus must be prioritised. Finally, generating RWD and cost-effectiveness studies in a region with limited resources is critical for decision-makers to define the incorporation of new technologies for the treatment of BC.

Subpopulation treatment effect pattern plot analysis: a prognostic model for distant recurrence-free survival to estimate delayed adjuvant chemotherapy initiation effect in triple-negative breast cancer

Introduction

Triple-negative breast cancer (TNBC) is a heterogeneous disease associated with a poor prognosis. Delaying in time to start adjuvant chemotherapy (TTC) has been related to an increased risk of distant recurrence-free survival (DRFS). We aimed to develop a prognostic model to estimate the effects of delayed TTC among TNBC risk subgroups.

Materials and methods

We analyzed 687 TNBC patients who received adjuvant chemotherapy at the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru). Database was randomly divided to create a discovery set (n=344) and a validation set (n=343). Univariate and multivariate Cox regression models were performed to identify prognostic factors for DRFS. Risk stratification was implemented through two models developed based on proportional hazard ratios from significant clinicopathological characteristics. Subpopulation treatment effect pattern plot (STEPP) analysis was performed to determine the best prognostic cut-off points for stratifying TNBC subgroups according to risk scores and estimate Kaplan-Meier differences in 10-year DRFS comparing TTC (≤30 vs.>30 days).

Results

In univariate analysis, patients aged ≥70 years (HR=4.65; 95% CI: 2.32-9.34; p=<0.001), those at stages pT3-T4 (HR=3.28; 95% CI: 1.57-6.83; p=0.002), and pN2-N3 (HR=3.00; 95% CI: 1.90-4.76; p=<0.001) were notably associated with higher risk. STEPP analysis defined three risk subgroups for each model. Model N°01 categorized patients into low (score: 0-31), intermediate (score:32-64), and high-risk (score: 65-100) cohorts; meanwhile, Model N°02: low (score: 0-26), intermediate (score: 27-55), and high (score: 56-100). Kaplan-Meier plots showed that in the discovery set, patients with TTC>30 days experienced a 17.5% decrease in 10-year DRFS rate (95%CI=6.7-28.3), and the impact was more remarkable in patients who belong to the high-risk subgroup (53.3% decrease in 10 years-DRFS rate). Similar results were found in the validation set.

Conclusions

We developed two prognostic models based on age, pT, and pN to select the best one to classify TNBC. For Model N°02, delayed adjuvant chemotherapy conferred a higher risk of relapse in patients ≥70 years and who were characterized by pT3/T4 and pN2/N3. Thus, more efforts should be considered to avoid delayed TTC in TNBC patients, especially those in high-risk subgroups.

Landscape of germline BRCA1/BRCA2 variants in breast and ovarian cancer in Peru

Background

There is an increasing amount of data from Latin America on the characterization of BRCA variants; however, there is limited information from Peru. We conducted a retrospective study to describe germline pathogenic/likely pathogenic(P/LP) variants and variants of uncertain/unknown significance (VUS) in the BRCA1 and BRCA2 genes in Peru, in patients with breast and ovarian cancer, candidates for treatment with poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors.

Methods

The patients were evaluated during the period 2019-2021. Genomic DNA was isolated from peripheral blood samples and targeted sequencing was performed using the Ampliseq BRCA panel. Genetic variant interpretation was carried out in accordance with the recommendations of the American College of Medical Genetics and ClinVar. During this period, 525 patients (143 with breast cancer and 382 with ovarian cancer) were studied.

Results

We found that 14.7% (21/143) of breast cancer patients and 20.7% (79/382) of ovarian cancer patients were carriers of P/LP variants in BRCA1/2. The most frequent pathogenic variants detected in BRCA1 were c.2105dupT (BIC: 2224insT, n=12, 18.75%), c.68_69delAG (BIC: 185delAG, n=6, 9.38%), c.140G>T and c.815_824dupAGCCATGTGG (n=5, 7.81%), while in BRCA2 were c.8023A>G (n=6, 16.67%), c.6024dupG (BIC: 6252insG, n=4, 11.11%), and c.9235delG (BIC: 9463delG, n=3, 8.33%). Regarding VUS, we found that 6.99% (10/143) of breast cancer patients and 7.33% (28/382) of ovarian cancer patients were carriers of a VUS in BRCA1/2. For BRCA1, the most frequent VUS was c.93C>G (n=2), and for BRCA2, c.5465A>T (n=4), c.3101T>C (n=3), c.205C>A and c.437T>C (n=2).

Conclusion

We found a frequency of 14.7% germline mutations in breast cancer patients and 20.7% in ovarian cancer patients. The most recurrent mutations were BRCA1 c.2105dupT and BRCA2 c.8023A>G. We found that BRCA2 c.8023A>G, c.6024dupG, and c.9235delG were not previously reported in Peruvian patients. BRCA1 c.2344dupA is a novel mutation that has not been previously reported in any database. The frequency of VUS in our cohort was 7.2%.

Access disparities and underutilization of germline genetic testing in Chilean breast cancer patients

PURPOSE

Latin American reports on genetic cancer risk assessments are scarce. In Chile, current breast cancer (BC) guidelines do not define strategies for germline genetic testing. Our study sought to quantify the disparities in access to genetic testing in Chilean BC patients, according to international standards and their clinical characteristics to explore improvement strategies.

METHODS

Retrospective analysis of invasive BC databases including patients treated in a Public Hospital (PH) and in an Academic Private Center (AC) in Santiago, Chile between 2012 and 2021.

RESULTS

Of 5438 BC patients, 3955 had enough data for National Comprehensive Cancer Network (NCCN) categorization. From these, 1911 (48.3%) fulfilled NCCN criteria for germline testing, of whom, 300 were tested for germline mutations and 268 with multigene panels. A total of 65 pathogenic variants were found in this subset. As expected, BRCA1/2 mutations were the most frequent (17.7%). Access to genetic testing was higher in AC versus PH (19.6% vs. 10.3%, p = 0.0001). Other variables associated with germline genetic testing were BC diagnosis after 2018, being 45 years old or younger at diagnosis, BC family history (FH), FH of ovarian cancer, non-metastatic disease, and triple-negative subtype.

CONCLUSION

In our cohort, 15% of BC patients who met NCCN criteria for germline testing were effectively tested. This percentage was even lower at the PH. Current recommendations encourage universal genetic testing for BC patients; however, our findings suggest that Chile is far from reaching such a goal and national guidelines in this regard are urgently needed. To our knowledge, this is the first study of its kind in Chile and Latin America.

Gastric adenocarcinoma with high‑level microsatellite instability: A case report

Gastric cancer (GC) ranks fifth on the list of the most common malignancies worldwide. In Peru, gastric neoplasms are considered the second leading cause of mortality among males. Among the molecular subgroups of GC, microsatellite instability presents a favorable prognosis due to its hypermutated phenotype, which activates immunosurveillance. The present study describes the case of a 75-year-old patient, who was admitted in the hospital with a history of upper gastrointestinal bleeding and recurrent hospital admission, due to severe anemia. The patient presented with pale skin, normal vital functions, slight swelling of the lower extremities, and abdominal distention and bloating upon a physical examination. An endoscopic examination revealed an infiltrating circular ulcerated lesion. The histopathological analysis identified a moderately differentiated intestinal-type adenocarcinoma with pathological stage T3N0M0. Tumor genomic profiling demonstrated alterations in 15 different genes with a tumor mutational burden of 28 mutations/Mb. Finally, the patient underwent a partial gastrectomy without pre-operative chemotherapy. After 4 days, the patient presented with post-operative complications for which he was re-operated on. The patient did not survive. To the best of our knowledge, in the present case, pernicious anemia was an early sign of GC and a gastroscopy had to be performed. Furthermore, MutS homolog 3 alterations probably conditioned the presence of multiple frame-shift mutations.

Pathogenic variant profile in DNA damage response genes correlates with metastatic breast cancer progression-free survival in a Mexican-mestizo population

Introduction

Metastatic breast cancer causes the most breast cancer-related deaths around the world, especially in countries where breast cancer is detected late into its development. Genetic testing for cancer susceptibility started with the BRCA 1 and 2 genes. Still, recent research has shown that variations in other members of the DNA damage response (DDR) are also associated with elevated cancer risk, opening new opportunities for enhanced genetic testing strategies.

Methods

We sequenced BRCA1/2 and twelve other DDR genes from a Mexican-mestizo population of 40 metastatic breast cancer patients through semiconductor sequencing.

Results

Overall, we found 22 variants -9 of them reported for the first time- and a strikingly high proportion of variations in ARID1A. The presence of at least one variant in the ARID1A, BRCA1, BRCA2, or FANCA genes was associated with worse progression-free survival and overall survival in our patient cohort.

Discussion

Our results reflected the unique characteristics of the Mexican-mestizo population as the proportion of variants we found differed from that of other global populations. Based on these findings, we suggest routine screening for variants in ARID1A along with BRCA1/2 in breast cancer patients from the Mexican-mestizo population.

Status of breast cancer in Latin American: Results of the breast cancer revealed initiative

The Breast Cancer Revealed initiative was designed and conducted to know the status of breast cancer at each point of breast cancer care, through i) prevention, ii) detection, iii) diagnosis, iv) treatment, and iv) the capacity of our health systems. The expert panel from 11 Latin American countries identified several strategies and proposed high impact priorities, including implementation of prevention policies, improve primary healthcare capacity for breast cancer screening, have adequate infrastructure to make effective and timely diagnoses, have a multidisciplinary team in the treatment process, access to a variety of treatments for all types of patients, have a coordinated and articulated system from primary care to specialized hospital. In a region with limited resources, prioritization in high-impact strategies for breast cancer control could lead to improved clinical outcomes and quality of life for our patients.

Improving equity in access to early diagnosis of cancer in different healthcare systems of Latin America: protocol for the EquityCancer-LA implementation-effectiveness hybrid study

INTRODUCTION

Healthcare fragmentation, a main cause for delay in cancer diagnosis and treatment, contributes to high mortality in Latin America (LA), particularly among disadvantaged populations. This research focuses on integrated care interventions, which have been limitedly implemented in the region. The objective is to evaluate the contextual effectiveness of scaling-up an integrated care intervention to improve early diagnosis of frequent cancers in healthcare networks of Chile, Colombia and Ecuador.

METHODS AND ANALYSIS

This research is two pronged: (A) quasi-experimental design (controlled before and after) with an intervention and a control healthcare network in each LA country, using an implementation-effectiveness hybrid approach to assess the intervention process, effectiveness and costs; and (B) case study design to analyse access to diagnosis of most frequent cancers. Focusing on the most vulnerable socioeconomic population, it develops in four phases: (1) analysis of delays and barriers to early diagnosis (baseline); (2) intervention adaptation and implementation (primary care training, fast-track referral pathway and patient information); (3) intracountry evaluation of intervention and (4) cross-country analysis. Baseline and evaluation studies adopt mixed-methods qualitative (semistructured individual interviews) and quantitative (patient questionnaire survey) methods. For the latter, a sample size of 174 patients with cancer diagnosis per healthcare network and year was calculated to detect a proportions difference of 15%, before and after intervention (α=0.05; β=0.2) in a two-sided test. A participatory approach will be used to tailor the intervention to each context, led by a local steering committee (professionals, managers, policy makers, patients and researchers).

ETHICS AND DISSEMINATION

This study complies with international and national legal stipulations on ethics. It was approved by each country's ethical committee and informed consent will be obtained from participants. Besides the coproduction of knowledge with key stakeholders, it will be disseminated through strategies such as policy briefs, workshops, e-tools and scientific papers.

Young Women with Breast Cancer in Resource-Limited Settings: What We Know and What We Need to Do Better

Young women with breast cancer (YWBC) account for a variable proportion of patients diagnosed with breast cancer around the globe, with a higher prevalence in resource-limited settings than in high-income countries. This group represents a unique population that warrants special attention due to specific biological considerations and age-specific supportive care issues. This review aims to explore existing knowledge regarding YWBC's needs, particularly in resource-restricted settings. To date, scarce information regarding the care of YWBC in resource-constrained countries is available, with most reports describing suboptimal care in terms of survivorship needs. Health care providers should implement actions to improve endocrine treatment adherence, referrals for fertility counseling and preservation, contraceptive use compliance, timely body image and sexual function interventions, comprehensive genetic risk assessments, and early quality of life and psychosocial health interventions. While high costs act as a barrier for optimal care in resource-limited settings, improving patient education represents a promising and cost-effective solution to improve patient care. Future research on developing tailored educational resources for YWBC in resource-limited settings should be considered a priority.

The current situation regarding the availability and accessibility of anticancer drugs for breast cancer in the Peruvian public health systems

The availability of effective, accessible, safe and high-quality anticancer drugs for the medical treatment of cancer is fundamental in ensuring optimal healthcare in the public health system in Peru. The main objective is to assess the current situation regarding anticancer drugs (termed ‘high-cost’) for breast cancer, as well as an analysis of the possible factors which negatively impact access to the Peruvian public health systems.There are similarities in the availability of anticancer drugs, since most treatments are covered by the Peruvian Ministry of Health. EsSalud offers an extra monoclonal antibody (pertuzumab) in the metastatic treatment stage. Meanwhile, the National Institute of Neoplastic Diseases (INEN), mainly for metastatic disease, has relied on more tested treatments over the last year. An agreement has been reached with the armed forces, which will enable patients to receive oncology care at the INEN and, thereby, benefit from the use of high-cost drugs.

Breast cancer mortality trends in Peruvian women

BACKGROUND

Breast cancer (BC) is the most common malignancy in Latin American women, but with a wide variability with respect to their mortality. This study aims to estimate the mortality rates from BC in Peruvian women and to assess mortality trends over 15 years.

METHODS

We calculated BC age-standardized mortality rate (ASMR) per 100,000 women-years using the world standard SEGI population. We estimated joinpoint regression models for BC in Peru and its geographical areas. The spatial analysis was performed using the Moran's I statistic.

RESULTS

In a 15-year period, Peru had a mortality rate of 9.97 per 100,000 women-years. The coastal region had the highest mortality rate (12.15 per 100,000 women-years), followed by the highlands region (4.71 per 100,000 women-years). In 2003, the highest ASMR for BC were in the provinces of Lima, Arequipa, and La Libertad (above 8.0 per 100,000 women-years), whereas in 2017, the highest ASMR were in Tumbes, Callao, and Moquegua (above 13.0 per women-years). The mortality trend for BC has been declining in the coastal region since 2005 (APC = - 1.35, p < 0.05), whereas the highlands region experienced an upward trend throughout the study period (APC = 4.26, p < 0.05). The rainforest region had a stable trend. Spatial analysis showed a Local Indicator of Spatial Association of 0.26 (p < 0.05).

CONCLUSION

We found regional differences in the mortality trends over 15 years. Although the coastal region experienced a downward trend, the highlands had an upward mortality trend in the entire study period. It is necessary to implement tailored public health interventions to reduce BC mortality in Peru.

Years of Potential Life Lost Because of Breast and Cervical Cancers in Guatemala

PURPOSE

Worldwide cervical and breast cancers are among the most commonly diagnosed cancers and are leading cause of cancer deaths among females in low- and middle-income countries. In Guatemala, breast and cervical cancers are the main cause of cancer-related deaths among women. Therefore, the aim of this study was to determine the years of potential life lost (YPLL) as an indicator of premature deaths as a result of breast and cervical cancers.

METHODS

Data on the number of deaths as a result of breast and cervical cancers (International Classification of Diseases [10th revision] codes C50 and C53) between 2012 and 2016 and age composition by quinquennials were retrieved from the Health Information System of the Guatemalan Health Ministry. On the basis of each individual’s age at death, YPLL was estimated for females between 20 and 70 years of age.

RESULTS

A total of 1,476 deaths related to breast and cervical cancers was reported over the study period. The trend in breast cancer mortality rate and YPLL did not change from 2012 to 2016. The cervical cancer mortality rate has decreased to 10 deaths per 1 million habitants (P = .046). There has been a reduction in YPLL because of cervical cancer, from 50.18 YPLL in 2012 to 29.19 YPLL by 2016, mainly in women between 30 and 34 years of age, in whom YPLL decreased from 600 to 112.50 (P = .046).

CONCLUSION

Cervical cancer screening has significantly reduced the mortality rate of this malignancy, and screening of breast cancer must include creating awareness of the disease and providing access to women at risk.

Landscape of Germline Mutations in DNA Repair Genes for Breast Cancer in Latin America: Opportunities for PARP-Like Inhibitors and Immunotherapy

Germline mutations in BRCA1 and BRCA2 (BRCA1/2) genes are present in about 50% of cases of hereditary breast cancer. Proteins encoded by these genes are key players in DNA repair by homologous recombination (HR). Advances in next generation sequencing and gene panels for breast cancer testing have generated a large amount of data on gene variants implicated in hereditary breast cancer, particularly in genes such as PALB2, ATM, CHEK2, RAD51, MSH2, and BARD1. These genes are involved in DNA repair. Most of these variants have been reported for Caucasian, Jewish, and Asian population, with few reports for other communities, like those in Latin American (LA) countries. We reviewed 81 studies from 11 LA countries published between 2000 and 2019 but most of these studies focused on BRCA1/2 genes. In addition to these genes, breast cancer-related variants have been reported for PALB2, ATM, CHEK2, BARD1, MLH1, BRIP1, MSH2, NBN, MSH6, and PMS2 genes. Some of these variants are unique to LA populations. This analysis may contribute to enhance breast cancer variant characterization, and thus to find therapies and implement precision medicine for LA communities.

The Molecular Mechanism of Epithelial-Mesenchymal Transition for Breast Carcinogenesis

The transforming growth factor-β (TGF-β) signaling pathway plays multiple regulatory roles in the tumorigenesis and development of cancer. TGF-β can inhibit the growth and proliferation of epithelial cells and induce apoptosis, thereby playing a role in inhibiting breast cancer. Therefore, the loss of response in epithelial cells that leads to the inhibition of cell proliferation due to TGF-β is a landmark event in tumorigenesis. As tumors progress, TGF-β can promote tumor cell invasion, metastasis, and drug resistance. At present, the above-mentioned role of TGF-β is related to the interaction of multiple signaling pathways in the cell, which can attenuate or abolish the inhibition of proliferation and apoptosis-promoting effects of TGF-β and enhance its promotion of tumor progression. This article focuses on the molecular mechanisms through which TGF-β interacts with multiple intracellular signaling pathways in tumor progression and the effects of these interactions on tumorigenesis.