Risk of Breast Cancer in Women with Mastitis: A Retrospective Population-Based Cohort Study

Mammalian Species-Specific Resistance to Mammary Cancer

Tumorigenesis in mammals is driven by inherited genetic variants, environmental factors and random errors during normal DNA replication that lead to cancer-causing mutations. These factors initiate uncontrolled cellular proliferation and disrupt the regulation of critical checkpoints. A few mammalian species possess unique protective mechanisms that enable them to resist widespread cancer development and achieve longevity. Tissue-specific tumor protection adds another layer of complexity to this diversity. Breast cancer is a leading cause of human mortality, particularly among females. Driven by the need for new strategies in treatment and prevention, this opinion article explores and supports the idea that herbivores are more resistant to mammary cancer than carnivores and omnivores. This diversity has occurred despite the remarkably similar basic mammary biology. Herbivores' meatless diet cannot explain the differences in cancer resistance, which have accompanied species segregation since the Jurassic era. To investigate the causes of this diversity, the characteristics of tumorigenesis in the human breast-and to a lesser extent in other carnivores-have been compared with data from retrospective analyses of bovine mammary tumor development across various locations over the past century. Well-established genomic, cellular, and systemic triggers of breast cancer exhibit different, or less pronounced tissue-specific activity in the bovine mammary gland, accompanied by novel bovine-specific protective mechanisms. Together, these factors contribute to the near absence of breast cancer in bovines and offer a basis for developing future anticancer strategies.

Unveiling the link between chronic inflammation and cancer

The highly nuanced transition from an inflammatory process to tumorigenesis is of great scientific interest. While it is well known that environmental stimuli can cause inflammation, less is known about the oncogenic modifications that chronic inflammation in the tissue microenvironment can bring about, as well as how these modifications can set off pro-tumorigenic processes. It is clear that no matter where the environmental factors come from, maintaining an inflammatory microenvironment encourages carcinogenesis. In addition to encouraging angiogenesis and metastatic processes, sustaining the survival and proliferation of malignant transformed cells, and possibly altering the efficacy of therapeutic agents, inflammation can negatively regulate the antitumoral adaptive and innate immune responses. Because chronic inflammation has multiple pathways involved in tumorigenesis and metastasis, it has gained recognition as a marker of cancer and a desirable target for cancer therapy. Recent advances in our knowledge of the molecular mechanisms that drive cancer's progression demonstrate that inflammation promotes tumorigenesis and metastasis while suppressing anti-tumor immunity. In many solid tumor types, including breast, lung, and liver cancer, inflammation stimulates the activation of oncogenes and impairs the body's defenses against the tumor. Additionally, it alters the microenvironment of the tumor. As a tactical approach to cancer treatment, these findings have underscored the importance of targeting inflammatory pathways. This review highlights the role of inflammation in cancer development and metastasis, focusing on its impact on tumor progression, immune suppression, and therapy resistance. It examines current anti-inflammatory strategies, including NSAIDs, cytokine modulators, and STAT3 inhibitors, while addressing their potential and limitations. The review emphasizes the need for further research to unravel the complex mechanisms linking inflammation to cancer progression and identify molecular targets for specific cancer subtypes.

Occult breast cancer in an older woman: A case report

Occult breast cancer (OBC) is a relatively rare clinical condition that can complicate differential diagnosis efforts and delay the administration of specific treatments. The individualized therapy of patients with OBC should be performed based on their clinical symptoms, imaging findings and pathological diagnosis. The present case study describes a 51-year-old woman with a painless left axillary tumor. The axillary lymph nodes of the patient were affected by invasive ductal carcinoma, as determined by histological analysis. However, the primary lesion was missed by numerous testing. The patient underwent surgery and testing for positron emission tomography/computed tomography (PET/CT). The present study comprehensively examined this case and offered a systematic analysis of the relevant scholarly works on the diagnosis, treatment and prognosis of OBC. Ultrasonography revealed the presence of three homogenous hypoechoic masses with irregular margins in the left axilla of the patient. PET/CT scanning identified multiple enlarged left axillary hypermetabolic lymph nodes. After that, the patient underwent a nipple-sparing mastectomy and an axillary lymphadenectomy. With the lymph nodes showing metastatic, infiltrating ductal carcinoma from the breast, ductal carcinoma in situ of the breast diagnosis was supported by a histological examination. Immunohistochemical staining revealed that resected lymph nodes were positive for both estrogen and progesterone receptors, consistent with the status of the breast as the primary tumor site. Following surgery, the patient underwent adjuvant chemotherapy treatment. At 12 months post-surgery, the patient remained well without evidence of disease. OBC cases lack the typical clinical and imaging findings associated with breast cancer, and a combination of axillary lymph node examination and immunohistochemistry is essential for accurately diagnosing affected patients. Ensuring the best patient outcomes necessitates accurate and prompt diagnosis, achieved by thorough physical examination, cautious utilization of diagnostic tools, personalized surgical interventions and histological investigation.

Whole-Exome Sequencing: Discovering Genetic Causes of Granulomatous Mastitis

Granulomatous mastitis (GM) is a rare, benign, but chronic and recurrent inflammatory breast disease that significantly impacts physical and psychological well-being. It often presents symptoms such as pain, swelling, and discharge, leading to diagnostic confusion with malignancy. The etiology of GM remains unclear, though autoimmune and multifactorial components are suspected. This study aimed to explore the genetic underpinnings of GM using whole-exome sequencing (WES) on 22 GM patients and 52 healthy controls to identify single nucleotide variants (SNVs) and copy number variations (CNVs) potentially linked to the disease. WES analysis revealed novel SNVs in six genes: BRCA2 (rs169547), CFTR (rs4727853), NCF1 (rs10614), PTPN22 (rs2476601), HLA-DRB1 (seven variants), and C3 (rs406514). Notably, most of these variants are associated with immune regulation and inflammatory pathways, supporting the hypothesis that GM is an autoimmune disease. However, all identified variants were classified as benign according to the American College of Medical Genetics and Genomics (ACMG) guidelines, necessitating further investigation into their potential functional effects. Despite conducting CNV analysis, no significant variations were identified. This study represents a foundational step in linking genetic predisposition to GM and highlights the need for integrating genetic, clinical, and functional data to better understand GM's pathophysiology. Future research should focus on larger cohorts, functional studies, and exploring multifactorial contributors to GM, including hormonal and environmental factors.

Is there an association between mastitis and breast cancer? a retrospective cohort study from Germany

PURPOSE

The aim of the study was to explore the association between mastitis and subsequent breast cancer.

METHODS

This retrospective cohort study included women aged ≥ 18 years with an initial mastitis diagnosis from 315 office-based gynecologists in Germany between January 2005 and December 2021. Women without mastitis were matched to women with mastitis using propensity score matching based on age, index year, average yearly consultation frequency during the follow-up period, and coexisting diseases such as obesity, benign mammary dysplasia, hypertrophy of the breast, unspecified lump of breast, and other disorders of the breast. The 10-year cumulative incidence of breast cancer for the mastitis-cohort and non-mastitis-cohort was studied with Kaplan-Meier curves using the log-rank test. The association between mastitis and breast cancer was studied separately for four age groups with univariable Cox regression analyses.

RESULTS

In the follow-up period of 7 months to 10 years after the index date, 2.9% of mastitis patients and 2.4% of matched non-mastitis patients were diagnosed with breast cancer. A Cox regression analysis revealed a significant association between mastitis and subsequent breast cancer (HR: 1.37; 95% CI: 1.11-1.70). According to the age-stratified analyses, a strong and significant association was only observed in the age group > 50 years (HR: 1.73; 95% 1.25-2.40).

CONCLUSION

The findings of our retrospective cohort study support an association between mastitis and subsequent breast cancer diagnoses in women aged > 50 years. The pathophysiological basis and possibility of confounders however requires further investigation.

Granulomatous mastitis masking ductal carcinoma in situ: A case report with literature review

Granulomatous mastitis (GM) is a rare inflammatory disorder that infrequently occurs with synchronous breast carcinoma. The present study reports the case of a patient who was initially diagnosed with recurrent GM, which eventually proved to be masking an underlying ductal carcinoma in situ (DCIS). A 30-year-old female presented with left breast pain. On clinical examination, there was a large, palpable and painful lump in the left breast, with axillary lymphadenopathy. Initially, the diagnosis was GM and conservative treatment was applied. Surgical resection was decided upon for the condition after it became recurrent, and the histopathological examination revealed extensive DCIS with GM. Later on, the patient underwent a mastectomy with an axillary sentinel lymph node biopsy. The postoperative follow-up was uneventful. In conclusion, tissue diagnosis has a key role in detecting DCIS masked by GM, especially in young females who are not undergoing regular mammogram screening. The present study shows the challenge that the specialists in this field may face when dealing with recurrent GM of the breast, and warns them to search for a second pathology such as the DCIS presented in the current case.

The effect of parity, breastfeeding history, and duration on clinical and pathological characteristics of breast cancer patients

Background/aim

The study is aimed to determine the relationship between the delivery and breastfeeding history of the patients and the clinicopathological properties of breast cancer.

Materials and methods

A questionnaire was utilized for the study, which included the age of diagnosis, the number of children at the time of diagnosis, the age of the children, and the breastfeeding period of each child.

Results

The study included 828 patients. The median age at diagnosis was 47 years for parous women and 42 years for nonparous women (p < 0.001). The tumor size of the patients diagnosed within the breastfeeding period was significantly larger compared to the other patients. Estrogen and progesterone receptor positivity were lower in patients diagnosed during breastfeeding. Additionally, the mean number of positive lymph nodes, dissected lymph nodes, and positive lymph node/dissected lymph node ratio in parous and breastfed patients with a nonmetastatic disease were statistically significantly higher in multivariable analysis than those patients who were nulliparous and have not breastfed.

Conclusion

Breast cancer is seen at a later age in patients who are parous than those who have never given birth. Patients who are parous and have breastfed tend to present with a higher stage of the disease.

Granulomatous mastitis with erythema nodosum: A breast cancer mimicking entity

We present the case of a 42-year-old Hispanic patient who consulted with a left breast mass that showed clinical and imaging signs of breast cancer. During preprocedural examination before needle biopsy, the patient was found to have bilateral, purplish-brown skin lesions on her lower legs, suggestive of erythema nodosum. This clinical finding raised the diagnostic suspicion of granulomatous mastitis, which was later confirmed by histopathology. Granulomatous mastitis is a rare, nonmalignant entity that should be considered in patients of childbearing age who present with a breast mass. The coexistence with erythema nodosum contributes to the clinical suspicion of granulomatous mastitis; the mechanism of this association and the optimal treatment approach remain unknown.

Stromal inflammation, fibrosis and cancer: An old intuition with promising potential

It is now well established that the biology of cancer is influenced by not only malignant cells but also other components of the tumour microenvironment. Chronic inflammation and fibrosis have long been postulated to be involved in carcinogenesis. Chronic inflammation can promote tumorigenesis via growth factor/cytokine-mediated cellular proliferation, apoptotic resistance, immunosuppression; and free-radical-induced oxidative deoxyribonucleic acid damage. Fibrosis could cause a perturbation in the dynamics of the tumour microenvironment, potentially damaging the genome surveillance machinery of normal epithelial cells. In this review, we will provide an in-depth discussion of various diseases characterised by inflammation and fibrosis that have been associated with an increased risk of malignancy. In particular, we will present a comprehensive overview of the impact of alterations in stromal composition on tumorigenesis, induced as a consequence of inflammation and/or fibrosis. Strategies including the application of various therapeutic agents with stromal manipulation potential and targeted cancer screening for certain inflammatory diseases which can reduce the risk of cancer will also be discussed.

Innate Immune Program in Formation of Tumor-Initiating Cells from Cells-of-Origin of Breast, Prostate, and Ovarian Cancers

Tumor-initiating cells (TICs), also known as cancer stem cells (CSCs), are cancer cells that can initiate a tumor, possess self-renewal capacity, and can contribute to tumor heterogeneity. TICs/CSCs are developed from their cells-of-origin. In breast, prostate, and ovarian cancers, progenitor cells for mammary alveolar cells, prostate luminal (secretory) cells, and fallopian tube secretory cells are the preferred cellular origins for their corresponding cancer types. These luminal progenitors (LPs) express common innate immune program (e.g., Toll-like receptor (TLR) signaling)-related genes. Microbes such as bacteria are now found in breast, prostate, and fallopian tube tissues and their corresponding cancer types, raising the possibility that their LPs may sense the presence of microbes and trigger their innate immune/TLR pathways, leading to an inflammatory microenvironment. Crosstalk between immune cells (e.g., macrophages) and affected epithelial cells (e.g., LPs) may eventually contribute to formation of TICs/CSCs from their corresponding LPs, in part via STAT3 and/or NFκB pathways. As such, TICs/CSCs can inherit expression of innate-immunity/TLR-pathway-related genes from their cells-of-origin; the innate immune program may also represent their unique vulnerability, which can be explored therapeutically (e.g., by enhancing immunotherapy via augmenting TLR signaling).

Mastitis and Risk of Breast Cancer: a Case Control-Retrospective Study and Mini-Review

Objective: To investigate a possible association between mastitis and breast cancer risk in a cohort of Greek women. Material and methods:A series of 343 women who visited two breast clinics in Greece and delivered live neonates were studied in our case-control retrospective study. The case group comprised women with breast cancer and the control group women without breast cancer. All participants were subjected to a clinical examination with breast ultrasound and those aged over 40 years underwent digital bilateral mammography. Results:The χ2 (chi-square) test was the statistical tool used by us. We noted a statistically significant relationship between mastitis and risk for breast cancer (p=0.04). Moreover, the relative risk for breast cancer among patients with mastitis was RR: 2.069. Conclusion:Our study showed a relation between mastitis and breast cancer. Mastitis could be a potential risk factor. Further studies with larger number of patients are mandatory in order to confirm this possible relationship.

The potential effects and mechanisms of breast inflammatory lesions on the occurrence and development of breast cancer

Breast cancer as the most common cancer in women has become the leading cause of cancer death for women. Although many inflammatory factors increase the risk of breast cancer, there are very few studies on the mechanisms by which inflammation affects the initiation and progression of breast cancer. Here, we profiled and compared the transcriptome of normal tissues, inflammatory breast tissues, benign breast tumors, and malignant breast tumors. To find key regulatory factors, a protein interaction network between characteristic modules in inflammatory lesions and ER-negative (ER⁻) breast cancer was constructed and inflammation-cancer interface genes were identified. We found that the transcriptional profile of inflammatory breast tissues was similar with ER⁻ malignant tumors, featured with low ER expression levels and similar immune signaling pathway activation. Through comprehensive protein network analysis, we identified the interface genes and chemokine signaling pathway that have the potential to promote inflammatory cancer transformation. These interface genes could be used as a risk factor to provide a certain basis for the clinical early detection and treatment of breast cancer. This is the first study to explore the association between breast inflammatory lesions and breast cancer at the transcriptome level. Our inflammation data and research results provide a basis for future inflammation-cancer transformation analysis.

Breast cancer risk in residents of Belarus exposed to Chernobyl fallout while pregnant or lactating: standardized incidence ratio analysis, 1997 to 2016

BACKGROUND

Pregnancy and lactation may constitute radiation-sensitive reproductive periods due to rapid cell proliferation and concentration of radioiodine in the lactating breast. However, there are limited epidemiological data among women exposed to radiation during these periods.

METHODS

We examined incidence of breast cancer in a cohort of 3214 women who were pregnant and/or lactating within 2 months (26 April to 30 June 1986) of the Chernobyl accident and residing in contaminated regions of Belarus. There were 33 breast cancers identified through linkage with the Belarusian National Cancer Registry. Breast cancer rates among women who were either pregnant and/or lactating were compared with population rates by calculating standardized incidence ratios (SIR) and 95% confidence intervals (CI) adjusting for attained age, oblast, urban/rural residence and calendar year.

RESULTS

Among women who were lactating, we found a greater than 2-fold increased risk of breast cancer compared with the general population, SIR = 2.49 (95% CI: 1.55, 3.75). In contrast, women who were pregnant were not at increased risk (SIR = 0.84 95% CI: 0.46, 1.38). The SIR was highest in women who were exposed at a younger age and at the earliest time period since the accident, though stratified analyses had limited sample sizes.

CONCLUSIONS

We found a significantly increased risk of breast cancer among women residing in contaminated areas of Belarus who were lactating at the time of the accident and may have had elevated exposure to radioiodine, when compared with the general population. Studies of breast cancer with individual radiation dose estimates among women exposed during lactation are warranted.

Actuarial Analysis of Survival among Breast Cancer Patients in Lithuania

Breast cancer is the most common cause of mortality due to cancer for women both in Lithuania and worldwide. Chances of survival after diagnosis differ significantly depending on the stage of disease at the time of diagnosis. Extended term periods are required to estimate survival of, e.g., 15–20 years. Moreover, since mortality of the average population changes with time, estimates of survival of cancer patients derived after a long period of observation can become outdated and can be no longer used to estimate survival of patients who were diagnosed later. Therefore, it can be useful to construct analytic functions that describe survival probabilities. Shorter periods of observation can be enough for such construction. We used the data collected by the Lithuanian Cancer Registry for our analysis. We estimated the chances of survival for up to 5 years after patients were diagnosed with breast cancer in Lithuania. Then we found analytic survival functions which best fit the observed data. At the end of this paper, we provided some examples for applications and directions for further research. We used mainly the Kaplan–Meier method for our study.