High-fat diet, but not duration of lactation, increases mammary gland lymphatic vessel function and subsequent growth of inflammatory breast cancer cells

Inflammatory breast cancer (IBC) presents as rapid-onset swelling and breast skin changes caused by tumor emboli in the breast and breast skin lymphatics. IBC has been linked with obesity and duration of breastfeeding, but how these factors affect IBC tumor progression is not clear. We modeled the simultaneous effects of diet and weaning in mice on in vivo lymphatic function; on IBC tumor growth; and on aspects of the mammary gland microenvironment before and after IBC (SUM149) xenograft inoculation. We hypothesized that weaning status and diet would have synergistic effects on lymphatic function and the breast microenvironment to enhance IBC tumor growth. Changes in lymphatic structure and function were characterized with in vivo near-infrared fluorescence (NIRF) imaging. Mice were fed either a high-fat diet (HFD; 60 kcal%) or a normal/low-fat diet (LFD; 10 kcal%), bred twice, and subjected to either normal-duration nursing (NW) or forced weaning (FW). SUM149 IBC tumors were implanted at 14 months; images were obtained before and after implantation. Multiparous mice fed HFD showed increased pre-tumor lymphatic pulsing in both the FW and NW groups relative to mice fed LFD. HFD promoted tumor growth independent of weaning time (P = 0.04). Pre-tumor lymphatic pulsing was associated with tumor volume at 8 weeks (P = 0.02) and was significantly correlated with expression of the lymphatic tracking ligand CCL21 (P = 0.05, Table 1). HFD significantly increased the numbers of monocyte-derived IBA1+, CD163+, and CD11c+ cells (P < 0.0001, P < 0.0001, P = 0.0005) in the contralateral, non-tumor-bearing mammary gland. Numbers of lymphangiogenic podoplanin+/IBA1+ macrophages were increased in the ducts of HFD and FW mice (all P < 0.003). HFD in nulliparous mice had a similar increase in lymphatic pulsing at 14 weeks (P = 0.006), indicating that this functional change was independent of parity. We conclude that HFD induced increases in mammary gland lymphatic function, assessed as pulsing rate before tumor initiation, and correlated with inflammation in the mammary gland and increased SUM149 tumor growth. The relationship between diet, lymphatic pulsing, and tumor growth warrants further investigation.

Abstract P2-26-15: CCR7 expression in Inflammatory breast cancer

Background: Inflammatory breast cancer is an aggressive breast cancer characterized by florid congestion of lymphovascular spaces by tumor emboli. CCR7 is an immune cell receptor that mediates traffic of immune cells into lymphatics that can be expressed on tumor cells. An RNA-seq screen of tumor promoting mammary glands in mice identified CCR7 as an upregulated signal in mammary glands that promoted IBC-like skin invasion. We examined the expression of CCR7 in IBC cell lines and patients to determine the prevalence of this receptor in IBC. Methods: Protein lysates from IBC and non-IBC cell lines were subjected to immunoblotting using anti CCR7 (R&D systems). An IBC tissue microarray from post-chemotherapy mastectomy specimens of 39 patients, each with three replicates was subjected to immunohistochemical staining for CCR7 (Invitrogen, catalog number MA5-31992) performed using a Leica Bond RX autostainer with an incubation time of 60 minutes at 1:15,000 after 20 minutes of heat-induced antigen retrieval at pH 6.0. In 15 cases there were no tumor cells observed in the cores. Staining was scored by an expert breast pathologist for intensity and percent tumor stained. Staining patterns were scored. Descriptive statistics were examined for representation by receptor subtype. Results: CCR7 staining was strong in all lines examined including MCF7, SUM149, SUM190, MDA-IBC, and SUM159. Among 24 IBC patient cores with tumor in the tissue, 23 (96%) expressed CCR7 in tumor, 15 with complete membranous staining and 9 with incomplete membranous staining. In one case with LVSI the emboli were CCR7 positive. Among the 24 positive cases, 22 were 3+ intensity while two were 2+. Nine CCR7+ cases were estrogen receptor (ER) ER+, 8 ER-, and 6 unknown. HER2 status is pending. Conclusions: CCR7 expression is present across tumor subtypes in IBC cell lines and in both ER+ and ER- patient tumors. Given developing novel pharmacologic targeting of CCR7, this target warrants further investigation in IBC and other breast cancers.

Citation Format: Wintana Balema, Savitri Krishnamurthy, Alison Lawrence, Megan Rodriguez, Richard Larson, Natalie Fowlkes, Naoto T. Ueno, Wendy Woodward. CCR7 expression in Inflammatory breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-26-15.

Abstract P1-24-06: Risk factor modeled microenvironment effects lymphatics activity and IBC invasiveness and progression

Background. Lymphovascular invasion (LVI) and breast tumor emboli within dermal and breast lymphatic vessels are prognostic for metastatic spread and poor outcomes, and are abundant in Inflammatory breast cancer (IBC). IBC is an aggressive breast cancer that presents suddenly with breast swelling and redness due to tumor emboli in lymphatics. Lack of breast-feeding and obesity are IBC risk factors. We sought to demonstrate the combinatorial effects of a high-fat diet and nursing on lymphatic function and compare these to IBC tumor induced changes in lymphatic function. We hypothesize that risk factors for aggressive breast cancer may alter lymphatic function in the normal gland prior to tumor initiation. Methods. Following two rounds of pregnancy in 20 multiparous SCID Beige immunocompromised mice, half of the mice were force weaned while half nursed pups. Prior to forced weaning, half of each of these groups were fed a high fat diet (HFD: 60 Kcal %, N = 10) while the other half received a low-fat diet (LFD: 10 Kcal %, N = 10). Consecutive dynamic near-infrared fluorescence (NIRF) lymphatic imaging was performed at 6-7 months (covid interruption) and 14 months after initiating the diet by injecting a near-IR fluorophore into the mammary fatpad and recording lymphatic pulsing over 8 minutes using V++. Matlab and ImageJ were used to quantify pulsing rates on the ventral lymphatics in each animal. Fatpads were subsequently inoculated with SUM149 IBC cells and imaging was repeated 16 months post diet initiation. Lymphatic imaging over time by HFD vs LFD was further studied in nulliparous animals. Tissues were collected for further analyses. ResultsData analysis prior to tumor injection, demonstrated lymphatic pulsing (pulses/4 minutes) increased over time in HFD force weaned (HFFW) and HFD nursing (HFN) animals only (65.5 vs 72.6, P=0.059; 60.1 vs 76.6, P=0.0099, respectively). Comparing HFFW and HFN to matched LFD groups (LFFW and LFN), at 14 weeks HFD was associated with increased pumping after forced weaning (62.3 vs. 72.6, P=0.074), and nursing (62.5 vs 76.6, P=0.0023). There was an increase in pulsing after tumor initiation (16 months after initiation of diet) in all groups (80.1, 84.1, 83.2, 82.4, P &gt; 0.05 all comparisons to initial timepoint). In a separate experiment examining HFD (N=5) vs LFD (N=5) in nulliparous mice, lymphatic contractile activity increased in all animals over. time, average ventral lymphatic contractile frequency for LFD and HFD at week 8,11 and 14 weeks after diet initiation were 5, 8.64, 15.9 pumps/4 mins vs 11.8, 18.5, 28.2 pumps/4 mins, (P = 0.01, 0.05, and 0.0005 respectively). ConclusionsHFD increased lymphatic pulsing rate over time to a significantly greater extent than LFD continuing over 14 months independent of reproductive and nursing status. Tumor initiation prompted further increased pulsing rates beyond that observed after HFD across all groups. The magnitude of the effect of HFD on lymphatic pulsing approached the rate after tumor initiation, while reproductive variables did not impact lymphatic pulsing. Further studies are warranted to demonstrate the relationship if any between lymphatic pumping pre-initiation and LVI after tumor initiation and examine the role of intervention on reducing LVI.

Citation Format: Wintana Balema, Janelle Morton, Richard Larson, Fred C Velasquez, Eva Sevick-Muraca, Wendy A Woodward. Risk factor modeled microenvironment effects lymphatics activity and IBC invasiveness and progression [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-24-06.

Why diagnosing inflammatory breast cancer is hard and how to overcome the challenges: a narrative review

OBJECTIVE

The purpose of this narrative review is to summarize the contributors to misdiagnosis or delayed diagnosis of inflammatory breast cancer (IBC) and strategies for expedient diagnosis.

BACKGROUND

Patients with IBC often report the disease as initially being misdiagnosed, most commonly as mastitis.

METHODS

We reviewed the literature on this challenging diagnosis by using sequential PubMed search criteria including IBC breast symptoms, IBC diagnosis, and IBC imaging modalities to augment the authors' knowledge of IBC. Other references were added from the manuscripts identified in the PubMed searches and from manuscript reviewers.

CONCLUSIONS

Several factors contribute to the delayed diagnosis of IBC. One important factor is that IBC is uncommon, and many generalists may not be aware of it in the differential diagnosis of breast skin symptoms. Several features of IBC contribute to the low sensitivity of mammography for its detection, and so the diagnosis is based on clinical factors and is thereby subjective. The presentation can be highly varied; classic textbook images that do not capture the range of presenting signs and symptoms across skin tones may contribute to missed diagnoses in patients with atypical presentations. In fact, the staging system of the American Joint Committee on Cancer, which requires erythema of the breast skin for diagnosis, may exclude patients with obvious global breast skin findings that are not explicitly red. We present an adapted algorithm for working up the undiagnosed inflammatory breast to ensure the timely and accurate diagnosis of IBC. We assert that frank, non-erythematous global skin signs in an enlarged breast with diffuse breast malignancy are sufficient to diagnose IBC if the timing of these signs and findings on biopsy are consistent. We further provide images of atypical IBC identified by global breast skin signs, including peau d'orange, consistent with IBC in the absence of frank erythema.

Lipocalin 2 promotes inflammatory breast cancer tumorigenesis and skin invasion

Inflammatory breast cancer (IBC) is an aggressive form of primary breast cancer characterized by rapid onset and high risk of metastasis and poor clinical outcomes. The biological basis for the aggressiveness of IBC is still not well understood and no IBC-specific targeted therapies exist. In this study, we report that lipocalin 2 (LCN2), a small secreted glycoprotein belonging to the lipocalin superfamily, is expressed at significantly higher levels in IBC vs non-IBC tumors, independently of molecular subtype. LCN2 levels were also significantly higher in IBC cell lines and in their culture media than in non-IBC cell lines. High expression was associated with poor-prognosis features and shorter overall survival in IBC patients. Depletion of LCN2 in IBC cell lines reduced colony formation, migration, and cancer stem cell populations in vitro and inhibited tumor growth, skin invasion, and brain metastasis in mouse models of IBC. Analysis of our proteomics data showed reduced expression of proteins involved in cell cycle and DNA repair in LCN2-silenced IBC cells. Our findings support that LCN2 promotes IBC tumor aggressiveness and offer a new potential therapeutic target for IBC.

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.

Abstract PS14-04: A picture worth a thousand words - “classic” inflammatory breast cancer (IBC) appearance associated with overall survival

Background: IBC is considered a clinical diagnosis characterized by rapid onset of diffuse skin changes in the setting of a breast cancer diagnosis. A wide variety of visual changes are accurately diagnosed as IBC. Here, we sought to determine whether the most subjectively “classic” appearing presentation (swollen, involved breast with nipple inversion and diffuse skin change) was associated with worse outcomes.

Method: We reviewed the images and charts of patients from the prospective IBC registry from the MD Anderson IBC Clinic. Breast medical photographs were reviewed by a non-expert and the visual presentation was scored as classic (as above), not classic, and in between. Comparative analyses were used to assess differences between patient groups using Chi-squared test, or Fisher’s exact test for categorical variables. Wilcoxon rank sum test was used for continuous measures. We used the Kaplan Meier estimator and the log-rank test to investigate association between scoring and survival distributions. Cox proportional hazard regression was employed to assess the impact of important covariates on the overall survival.

Results: We analyzed 245 IBC patients with median age 55 (range, 26-81), M0 vs. M1 status (157 and 88 patients, respectively), 68 TNBC vs. 177 non-TNBC patients. The classic presentation was significantly associated with smoking, post-menopausal status, and metastatic disease at presentation (P = 0.002, 0.018, and 0.004, respectively). Presentation was significantly associated with OS in univariate analysis (P &lt; 0.001). 10 year overall survival was 57% vs. 33% for classic (score 3) versus non-classic or in between presentation. The multivariable Cox regression model adjusting for clinical staging (P&lt;0.001) and TNBC status (P&lt;0.001) demonstrated classic presentation score was significantly associated with poorer OS time (HR 2.4, CI 1.6-3.6, p&lt;0.001).

Conclusions: A visual inspection of presentation photograph for “classic” appearance, obvious swelling, skin change, and nipple inversion, independently predicted poorer OS in IBC. Further work is warranted to understand the differences in classic and non-classic presentations, and the relationship between smoking and breast cancer presentation.

Citation Format: Wintana Balema, Diane Liu, Yu Shen, Randa El-Zein, Megumi Kai, Beth Overmoyer, Kathy D Miller, Carisa Le-Petross, Naoto T Ueno, Wendy A Woodward. A picture worth a thousand words - “classic” inflammatory breast cancer (IBC) appearance associated with overall survival [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS14-04.

Abstract P6-15-04: Modeling limited breastfeeding and diet on IBC like tumor progression

Introduction/Motivation: We previously reported IBC patients with limited breast-feeding history have a worse prognosis than those with greater breast feeding history. Further, we reported pregnancy related factors including multiple early pregnancies and not breast feeding as well as obesity are risk factors for triple negative and ER+ subtypes. Significant evidence suggests the microenvironment drives IBC symptoms and growth pattern. We sought to characterize the impact of purported risk factors on tumor growth, IBC-like skin symptoms and mammary gland microenvironment in animal models.

Methods: We commissioned breeding of nulliparous, multiparous (x 2) force weaned, and multiparous naturally weaned (labeled nursing) mice. Mice in each of the three groups were fed either a low fat (10 Kcal %) or high fat (60 Kcal %) diet for three weeks before tumor cell injections. SUM 149 GFP Luc were injected into the left ventral #4 mammary fat pad. Mice were sacrificed, scored for the IBC-like symptom of gross skin invasion or evident skin symptoms, and tissue from the contralateral mammary gland were sectioned and stained with H and E. Analysis was performed on the 31 animals that developed primary tumors and were scored for skin invasion at the time of resection. Of these 26 mice had contralateral gland tissue assessed by H and E. Phenotypes including duct dilation, degree of adipose tissue, duct density, inflammation and necrosis were scored manually, 1-3 scale. Quadratic mixed models with random intercept were fitted to compare tumor growth. Fisher’s exact test and T-tests were performed to compare variables.

Results: Tumor incidence and latency were not different by risk factor group. Tumor growth was faster in multiparous force weaned versus others, P &lt; 0.0001, but unchanged by diet, P = 0.187. Force weaned animals on a high fat diet had a trend for increased skin invasion compared to others (force weaned high fat diet vs. other 85% vs. 42%; P = 0.08) suggesting a synergy for this IBC-like symptom. Contralateral gland ductal density (less dense) and ductal dilation (not dilated) were normal histologic variables which correlated with skin invasion on the tumor side (P =0.006 and P = 0.011, respectively). Gland density but not dilated ducts trended to correlation with force weaning, P = 0.07, but not diet.

Discussion: In this effect size finding pilot study, combined risk factors were associated with a higher incidence of skin invasion of SUM149 xenografts. Changes in the microenvironment in the contralateral gland typical of involution were significantly associated with skin invasion, and gland density trends towards association with force weaning. These data provide provocative pilot results linking histologic effects in the microenvironment to tumor growth characteristics and support the hypothesis that involution induced by forced weaning may facilitate IBC-like tumor growth. These studies facilitate well-powered additional work to establish mechanism and automate normal tissue evaluation.

Citation Format: Wintana Balema, Richard Larson, Renae Van Whye, Rong Ye, Jing Ning, Omar Rahal, Shane Stecklein, Savitri Krishnamurthy, Randa El-Zein, Wendy Woodward. Modeling limited breastfeeding and diet on IBC like tumor progression [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-15-04.