XIAP overexpressing inflammatory breast cancer patients have high infiltration of immunosuppressive subsets and increased TNFR1 signaling targetable with Birinapant

OBJECTIVE

To assess the expression pattern of X-linked inhibitor of apoptosis protein (XIAP), a cellular stress sensor, and delineate the associated changes in the tumor immune microenvironment (TiME) for prognostic value and new therapeutic targets in inflammatory breast cancer (IBC).

METHODS

Immunohistochemistry was conducted to assess the spatial localization of immune subsets, XIAP, and PDL1 expression in IBC and non-inflammatory breast cancer (nIBC) pretreatment tumors (n = 142). Validation and further exploration were performed by gene expression analysis of patient tumors along with signaling studies in a co-culture model.

RESULTS

High XIAP in 37/81 IBC patients correlated significantly with high PD-L1, increased infiltration of FOXP3+ Tregs, CD163+ tumor-associated macrophages (TAMs), low CD8/CD163 ratio in both tumor stroma (TS) and invasive margins (IM), and higher CD8+ T cells and CD79α+ B cells in the IM. Gene set enrichment analysis identified cellular stress response- and inflammation-related genes along with tumor necrosis factor receptor 1 (TNFR1) expression in high-XIAP IBC tumors. Induction of TNFR1 and XIAP was observed when patient-derived SUM149 IBC cells were co-cultured with human macrophage-conditioned media simulating TAMs, further demonstrating that the TNF-α signaling pathway is a likely candidate governing TAM-induced XIAP overexpression in IBC cells. Finally, addition of Birinapant, a pan IAP antagonist, induced cell death in the pro-survival cytokine-enriched conditions.

CONCLUSION

Using immunophenotyping and gene expression analysis in patient biospecimens along with in silico modeling and a preclinical model with a pan-IAP antagonist, this study revealed an interplay between increased TAMs, TNF-α signaling, and XIAP activation during (immune) stress in IBC. These data demonstrate the potential of IAP antagonists as immunomodulators for improving IBC therapeutic regimens.

Identification of barriers at the primary care provider level to improve inflammatory breast cancer diagnosis and management

The purpose of this study, based in the United States, was to evaluate knowledge gaps and barriers related to diagnosis and care of inflammatory breast cancer (IBC), a rare but lethal breast cancer subtype, amongst Primary Care Providers (PCP) as they are often the first point of contact when patients notice initial symptoms. PCP participants in the Duke University Health System, federally qualified health center, corporate employee health and community practices, nearby academic medical center, Duke physician assistant and advanced practice nurse leadership program alumni were first selected in a convenience sample and for semi-structured interviews (n = 11). Based on these data, an online survey tool was developed and disseminated (n = 78) to assess salient measures of IBC diagnosis, health disparity factors, referral and care coordination practices, COVID-19 impact, and continuing medical education (CME). PCP reported access to care and knowledge gaps in symptom recognition (mean = 3.3, range 1-7) as major barriers. Only 31 % reported ever suspecting IBC in a patient. PCP (n = 49) responded being challenged with referral delays in diagnostic imaging. Additionally, since the COVID-19 pandemic started, 63 % reported breast cancer referral delays, and 33 % reported diagnosing less breast cancer. PCP stated interest in CME in their practice for improved diagnosis and patient care, which included online (53 %), lunch time or other in-service training (33 %), patient and provider-facing websites (32 %). Challenges communicating rare cancer information, gaps in confidence in diagnosing IBC, and timely follow-up with patients and specialists underscores the need for developing PCP educational modules to improve guideline-concordant care.

The role of breastfeeding in breast cancer prevention: a literature review

Breast cancer stands as the most prevalent malignancy globally. Despite the array of treatment options, its mortality rate continues to rise annually. Thus, reevaluation of factors directly linked to breast cancer emergence is imperative, alongside the development of more effective preventive measures. Estrogen levels, profoundly tied to reproduction, play a pivotal role in breast cancer development. Speculation centers on the potential of breastfeeding to mitigate cancer risk in women. However, the precise mechanism remains elusive. Breastfeeding is a modifiable reproductive factor extensively studied. Studies highlight a direct connection between lack of breastfeeding and breast cancer emergence, potentially linked to DNA methyltransferase expression alteration, aberrant methylation levels, pregnancy-associated plasma protein-A, cellular microenvironment, and oncogenes. This study reviews recent mechanisms underlying breastfeeding's role in reducing breast cancer incidence.

Loss of IRF5 increases ribosome biogenesis leading to alterations in mammary gland architecture and metastasis

Despite the progress made in identifying cellular factors and mechanisms that predict progression and metastasis, breast cancer remains the second leading cause of death for women in the US. Using The Cancer Genome Atlas and mouse models of spontaneous and invasive mammary tumorigenesis, we identified that loss of function of interferon regulatory factor 5 (IRF5) is a predictor of metastasis and survival. Histologic analysis of Irf5 -/- mammary glands revealed expansion of luminal and myoepithelial cells, loss of organized glandular structure, and altered terminal end budding and migration. RNA-seq and ChIP-seq analyses of primary mammary epithelial cells from Irf5 +/+ and Irf5 -/- littermate mice revealed IRF5-mediated transcriptional regulation of proteins involved in ribosomal biogenesis. Using an invasive model of breast cancer lacking Irf5 , we demonstrate that IRF5 re-expression inhibits tumor growth and metastasis via increased trafficking of tumor infiltrating lymphocytes and altered tumor cell protein synthesis. These findings uncover a new function for IRF5 in the regulation of mammary tumorigenesis and metastasis.

Highlights

Loss of IRF5 is a predictor of metastasis and survival in breast cancer.IRF5 contributes to the regulation of ribosome biogenesis in mammary epithelial cells.Loss of IRF5 function in mammary epithelial cells leads to increased protein translation.

Assessing Knowledge and Barriers at the Primary Care Provider Level that Contribute to Disparities in Inflammatory Breast Cancer Diagnosis and Treatment

Purpose

The purpose of this study was to evaluate knowledge gaps and barriers related to diagnosis and care of inflammatory breast cancer (IBC), a rare but most lethal breast cancer subtype, amongst Primary Care Providers (PCP) as they are often the first point of contact when patients notice initial symptoms.

Methods

PCP participants within Duke University Health System, federally qualified health center, corporate employee health and community practices, nearby academic medical center, Duke physician assistant, and nurse leadership program alumni were first selected in a convenience sample (n=11) for semi-structured interviews (n=11). Based on these data, an online survey tool was developed and disseminated (n=78) to assess salient measures of IBC diagnosis, health disparity factors, referral and care coordination practices, COVID impact, and continued medical education (CME).

Results

PCP reported access to care and knowledge gaps in symptom recognition (mean = 3.3, range 1-7) as major barriers. Only 31% reported ever suspecting IBC in a patient. PCP (n=49) responded being challenged with referral delays in diagnostic imaging. Additionally, since the COVID-19 pandemic started, 63% reported breast cancer referral delays, and 33% reported diagnosing less breast cancer. PCP stated interest in CME in their practice for improved diagnosis and patient care, which included online (53%), lunch time or other in-service training (33%), patient and provider-facing websites (32%).

Conclusions

Challenges communicating rare cancer information, gaps in confidence in diagnosing IBC, and timely follow-up with patients and specialists underscores the need for developing PCP educational modules to improve guideline-concordant care.

Inflammatory breast cancer appearance at presentation is associated with overall survival

Background

Inflammatory breast cancer (IBC) is a clinical diagnosis. Here, we examined the association of a “classic” triad of clinical signs, swollen involved breast, nipple change, and diffuse skin change, with overall survival (OS).

Method

Breast medical photographs from patients enrolled on a prospective IBC registry were scored by two independent reviewers as classic (triad above), not classic, and difficult to assign. Chi‐squared test, Fisher's exact test, and Wilcoxon rank‐sum test were used to assess differences between patient groups. Kaplan–Meier estimates and the log‐rank test and Cox proportional hazard regression were used to assess the OS.

Results

We analyzed 245 IBC patients with median age 54 (range 26–81), M0 versus M1 status (157 and 88 patients, respectively). The classic triad was significantly associated with smoking, post‐menopausal status, and metastatic disease at presentation (p = 0.002, 0.013, and 0.035, respectively). Ten‐year actuarial OS for not classic and difficult to assign were not significantly different and were grouped for further analyses. Ten‐year OS was 29.7% among patients with the classic sign triad versus 57.2% for non‐classic (p < 0.0001). The multivariate Cox regression model adjusting for clinical staging (p < 0.0001) and TNBC status (<0.0001) demonstrated classic presentation score significantly associated with poorer OS time (HR 2.6, 95% CI 1.7–3.9, p < 0.0001).

Conclusions

A triad of classic IBC signs independently predicted OS in patients diagnosed with IBC. Further work is warranted to understand the biology related to clinical signs and further extend the understanding of physical examination findings in IBC.

Recent advances in the epidemiology of inflammatory breast cancer

The survival after the diagnosis of inflammatory breast cancer (IBC) has been steadily improving for the past few decades. This has been due to advances in the knowledge of IBC in a number of fields, including epidemiology, molecular biology, and medical management. In this review we summarize some of the most important recent advances in these fields and suggest possible opportunities for continued improvement.