Comprehensive strategies in breast cancer-related lymphedema prevention: insights from a multifaceted program.

Background: Breast cancer-related lymphedema (BCRL) profoundly impacts patients' quality of life, causing heightened depression, anxiety, and physical limitations. Surgical removal of the axillary nodes, combined with radiation therapy, is a significant risk factor for BCRL. Smarter axillary surgery, coupled with early detection and fostering lymphedema education, significantly improves BCRL management, promoting timely diagnosis and treatment. A lymphedema prevention program encompassing all these factors can significantly aid in preventing, treating, and reducing the severity of BCRL cases. Therefore, our study aims to share our insights and experiences gained from implementing a lymphedema prevention program at our institution. Methods & Results: At our institution, axillary reverse mapping (ARM) is performed on all patients undergoing axillary surgery. We surveil these patients with pre- and postoperative SOZO® measurements using bioimpedance spectroscopy to detect sub-clinical lymphedema. Concerning education, we use a 3-pronged approach with surgeons, nurse practitioners, and video representation for patients. We have had 212 patients undergo the ARM procedure since 2019, with three (1.41%) developing persistent lymphedema. Conclusion: Our study underscores the significance of a comprehensive lymphedema prevention program, integrating smarter axillary surgery, early detection, and patient education. The lymphedema rate of 1.41% not only validates the success rate of these interventions but also advocates for their widespread adoption to enhance the holistic care of breast cancer survivors. As we continue to refine and expand our program, further research, and long-term follow-up are crucial to improve prevention strategies continually and enhance the overall well-being of individuals at risk of BCRL.

Axillary Reverse Mapping Aids in Reducing the Rates of Breast Cancer-Related Lymphedema in Underserved Ethnically Diverse Population.

BACKGROUND: Breast cancer-related lymphedema (BCRL) poses a significant risk following sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND), particularly affecting ethnic minorities, with a twofold increased risk. Axillary reverse mapping (ARM), a novel technique, shows potential in reducing BCRL rates, yet its utility in ethnic minorities lacks sufficient exploration. Therefore, our study aims to investigate the utility and outcomes of ARM on BCRL in an ethnic diverse group. METHODS: A retrospective chart review of ARM patients from January 2019 to July 2022 was conducted, monitoring patients over 24 months at 3-month intervals using SOZO® scores, with comparisons with preoperative baselines. RESULTS: Of the 212 patients, 83% belonged to ethnic minorities. SLNB was performed in 83%, ALND in 17%, and 62.3% underwent radiation therapy. Positive lymph nodes were found in 31.6%, with 22.2% exhibiting blue nodes and 25.9% exhibiting blue lymphatics. Of identified blue nodes, 70.2% were excised, including 51.5% crossover nodes. Lymphedema occurred in 3 patients, resulting in a BCRL rate of 1.4%. Compared with an historical BCRL incidence of 40.4% following ALND in ethnic minorities, our study reported a significantly lower rate of 8% (p < 0.001). CONCLUSION: The ARM procedure can significantly lower BCRL in ethnic minority groups. The combination of ARM and bioimpedance spectroscopy led to a remarkably low BCRL rate of 1.4%. Notably, none of the patients in our study developed an axillary recurrence at 24-month follow-up. Nevertheless, future studies with larger sample sizes are warranted to better understand the utility of the ARM technique in this population.

Mucoepidermoid carcinoma-a rare salivary gland-type tumor of the breast: are we dealing with primary or secondary?-a case report and literature review.

Background: Salivary gland-like tumors are extremely unusual in the breast, and their histology is very similar to primary salivary gland neoplasms. Mucoepidermoid carcinoma (MEC), a common salivary gland tumor, displays an infrequent occurrence in the breast, accounting for a mere 0.2-0.3% incidence. Given its rarity, it is critical to accurately distinguish it from metastatic cases before diagnosing it as a primary breast MEC for appropriate treatment. Currently, there is no consensus on the treatment of MEC, and there is a paucity of literature highlighting the ideal treatment modality, especially for estrogen receptor (ER)-positive cancers. Therefore, the aim of our case report was to underscore the diagnostic process, surgical and adjunctive treatments for our patient with ER-positive, progesterone receptor (PR)-negative and human epidermal growth factor receptor 2 (HER2)-negative MEC while also conducting a literature review to contribute to the limited existing data. Case Description: A 67-year-old African American woman presented with a lobulated 3.1-cm left breast mass on mammography, for which she underwent ultrasound-guided core needle biopsy that revealed invasive carcinoma with squamous differentiation. The carcinoma was ER-positive, PR-negative and HER2-negative. Subsequently, she underwent a lumpectomy with sentinel lymph node biopsy. Her final pathology revealed an intermediate-grade MEC with negative lymph nodes. She had a past medical history of benign salivary gland tumor, as well as a family history of BReast CAncer gene 1 (BRCA1)-associated breast cancer in her daughter. Conclusions: MEC of the breast is a rare tumor with a relatively favorable overall prognosis. The early and precise diagnosis of this condition plays a pivotal role in formulating effective treatment strategies and ensuring positive survival rates. Nonetheless, future studies are recommended to further explore the role of surgical approaches and adjuvant therapy to improve treatment outcomes.

Does Nipple-Ward Positive Margin Contribute to a Higher Rate of Re-Excision Procedures After a Lumpectomy with Pathology-Confirmed Positive Margins? A Retrospective Study.

Background: Positive margins on lumpectomy specimens are associated with a twofold increased risk of local breast tumor recurrence. Prior literature has demonstrated various techniques and modalities for assessing margin status to reduce re-excision rates. However, there is paucity of literature analyzing which margin contributes to the highest re-excision rates. Therefore, the primary aim of the study was to investigate whether the nipple-ward margins resulted in a higher rate of re-excision in our patient population. Methods:  A retrospective chart review was performed on patients who had re-excision surgery. Nipple-ward margin was identified by correlating radiological and pathological reports. A cut-off of more than 25% was used to demonstrate correlation between nipple-ward margin and re-excision rate. Results: A total of 98 patients' data were analyzed, with 41 (41.8%), 14 (14.3%), 5 (5.1%), and 38 (38.8%) diagnosed with DCIS, IDC, ILC, and mixed pathology on their margins, respectively. Overall, 48% (n=47) of the positive margins were nipple-ward, with 44.7% (n=21) reporting DCIS. Upon stratification, 45 (45.9%) cases were single-margin positive, with 26 (57.8%) being nipple-ward. Furthermore, the remaining 53 (54.1%) patients had multiple positive margins, with 21 (39.6.7%) nipple-ward cases. Conclusion: Positive nipple-ward margins significantly contribute to a higher re-excision rate p < 0.001; 48% of re-excision surgeries had positive nipple-ward margins, and 57.8% of positive single-margin cases were nipple-ward. Taking an additional shave during initial lumpectomy decreases re-excision rates. However, planning a lumpectomy procedure with a more elliptical rather than a spherical resection with additional cavity shave (ie, larger volume) in the nipple-ward direction and minimizing the remaining cavity shaves so the total volume resected remains unchanged. Nevertheless, future studies with larger sample sizes are required to bolster our findings.

Can the Clinical Utility of iBreastExam, a Novel Device, Aid in Optimizing Breast Cancer Diagnosis? A Systematic Review.

PURPOSE: A portable, cost-effective, easy-to-use, hand-held Intelligent Breast Exam (iBE), which is a wireless, radiation-free device, may be a valuable screening tool in resource-limited settings. While multiple studies evaluating the use of iBE have been conducted worldwide, there are no cumulative studies evaluating the iBE's performance. Therefore this review aims to determine the clinical utility and applicability of iBE compared with clinical breast examinations, ultrasound, and mammography and discuss its strengths and weaknesses when performing breast-cancer screening. METHODS: A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four electronic databases were searched: PubMed, Cochrane Library, Web of Science, and Google Scholar. RESULTS: The review included 11 studies with a total sample size of 16,052 breasts. The mean age ranged from 42 to 58 years. The sensitivity and specificity of the iBE ranged from 34.3% to 86% and 59% to 94%, respectively. For malignant lesions, iBE demonstrated a moderate to higher diagnostic capacity ranging from 57% to 93% and could identify tumor sizes spanning from 0.5 cm to 9 cm. CONCLUSION: Our findings underscore the potential clinical utility and applicability of iBE as a prescreening and triaging tool, which may aid in reducing the burden of patients undergoing diagnostic imaging in lower- and middle-income countries. Furthermore, iBE has shown to diagnose cancers as small as 0.5 cm, which can be a boon in early detection and reduce mortality rates. However, the encouraging results of this systematic review should be interpreted with caution because of the device's low sensitivity and high false-positive rates.

Case Report: Bilateral targeted intraoperative radiotherapy: a safe and effective alternative for synchronous bilateral breast cancer.

Background: The incidence of bilateral breast cancer (BBC) ranges from 1.4% to 11.8%. BBC irradiation is a challenge in current clinical practice due to the large target volume that must be irradiated while minimizing the dose to critical organs. Supine or prone breast techniques can be used, with the latter providing better organ sparing; both, however, result in lengthy treatment times. The use of Intra-operative radiotherapy (IORT) in breast cancer patients who choose breast conservation has been highlighted in previous studies, but there is a scarcity of literature analyzing the utility and applicability of IORT in BBC. This case series aims to highlight the applicability of administering bilateral IORT in patients with BBC. Case reports: Five patients with bilateral early-stage breast cancer (or DCIS) were treated with breast-conserving surgery followed by bilateral IORT. Of the 10 breast cancers, 8 were diagnosed as either DCIS or IDC, while the other 2 were diagnosed as invasive lobular carcinoma and invasive carcinoma, respectively. During surgery, all patients received bilateral IORT. Furthermore, 1 patient received external beam radiation therapy after her final pathology revealed grade 3 DCIS. The IORT procedure was well tolerated by all five patients, and all patients received aromatase inhibitors as adjuvant therapy. Additionally, none of these patients showed evidence of disease after a 36-month median follow-up. Conclusion: Our findings demonstrate the successful use of IORT for BCS in patients with BBC. Furthermore, none of the patients in our study experienced any complications, suggesting the feasibility of the use of IORT in BBC. Considering the benefits of improved patient compliance and a reduced number of multiple visits, IORT may serve as an excellent patient-centered alternative for BBC. Future studies are recommended to reinforce the applicability of IORT in patients with BBC.

Racial disparity in tumor microenvironment and distant recurrence in residual breast cancer after neoadjuvant chemotherapy.

Black, compared to white, women with residual estrogen receptor-positive (ER+) breast cancer after neoadjuvant chemotherapy (NAC) have worse distant recurrence-free survival (DRFS). Such racial disparity may be due to difference in density of portals for systemic cancer cell dissemination, called TMEM doorways, and pro-metastatic tumor microenvironment (TME). Here, we evaluate residual cancer specimens after NAC from 96 Black and 87 white women. TMEM doorways are visualized by triple immunohistochemistry, and cancer stem cells by immunofluorescence for SOX9. The correlation between TMEM doorway score and pro-metastatic TME parameters with DRFS is examined using log-rank and multivariate Cox regression. Black, compared to white, patients are more likely to develop distant recurrence (49% vs 34.5%, p = 0.07), receive mastectomy (69.8% vs 54%, p = 0.04), and have higher grade tumors (p = 0.002). Tumors from Black patients have higher TMEM doorway and macrophages density overall (p = 0.002; p = 0.002, respectively) and in the ER+/HER2- (p = 0.02; p = 0.02, respectively), but not in the triple negative disease. Furthermore, high TMEM doorway score is associated with worse DRFS. TMEM doorway score is an independent prognostic factor in the entire study population (HR, 2.02; 95%CI, 1.18-3.46; p = 0.01), with a strong trend in ER+/HER2- disease (HR, 2.38; 95%CI, 0.96-5.95; p = 0.06). SOX9 expression is not associated with racial disparity in TME or outcome. In conclusion, higher TMEM doorway density in residual breast cancer after NAC is associated with higher distant recurrence risk, and Black patients are associated with higher TMEM doorway density, suggesting that TMEM doorway density may contribute to racial disparities in breast cancer.

Assessment of MRI to estimate metastatic dissemination risk and prometastatic effects of chemotherapy.

Metastatic dissemination in breast cancer is regulated by specialized intravasation sites called "tumor microenvironment of metastasis" (TMEM) doorways, composed of a tumor cell expressing the actin-regulatory protein Mena, a perivascular macrophage, and an endothelial cell, all in stable physical contact. High TMEM doorway number is associated with an increased risk of distant metastasis in human breast cancer and mouse models of breast carcinoma. Here, we developed a novel magnetic resonance imaging (MRI) methodology, called TMEM Activity-MRI, to detect TMEM-associated vascular openings that serve as the portal of entry for cancer cell intravasation and metastatic dissemination. We demonstrate that TMEM Activity-MRI correlates with primary tumor TMEM doorway counts in both breast cancer patients and mouse models, including MMTV-PyMT and patient-derived xenograft models. In addition, TMEM Activity-MRI is reduced in mouse models upon treatment with rebastinib, a specific and potent TMEM doorway inhibitor. TMEM Activity-MRI is an assay that specifically measures TMEM-associated vascular opening (TAVO) events in the tumor microenvironment, and as such, can be utilized in mechanistic studies investigating molecular pathways of cancer cell dissemination and metastasis. Finally, we demonstrate that TMEM Activity-MRI increases upon treatment with paclitaxel in mouse models, consistent with prior observations that chemotherapy enhances TMEM doorway assembly and activity in human breast cancer. Our findings suggest that TMEM Activity-MRI is a promising precision medicine tool for localized breast cancer that could be used as a non-invasive test to determine metastatic risk and serve as an intermediate pharmacodynamic biomarker to monitor therapeutic response to agents that block TMEM doorway-mediated dissemination.

Racial disparity in distant recurrence-free survival in patients with localized breast cancer: A pooled analysis of National Surgical Adjuvant Breast and Bowel Project trials.

BACKGROUND: Black race is associated with worse outcome in patients with breast cancer. The distant relapse-free survival (DRFS) between Black and White women with localized breast cancer who participated in National Cancer Institute-sponsored clinical trial was evaluated. METHODS: Pooled data were analyzed from 8 National Surgical Adjuvant Breast and Bowel Project (NSABP) trials including 9702 women with localized breast cancer treated with adjuvant chemotherapy (AC, n = 7485) or neoadjuvant chemotherapy (NAC, n = 2217), who self-reported as Black (n = 1070) or White (n = 8632) race. The association between race and DRFS was analyzed using log-rank tests and multivariate Cox regression. RESULTS: After adjustment for covariates including age, tumor size, nodal status, body mass index and taxane use, and treatment (AC vs NAC), Black race was associated with an inferior DRFS in estrogen receptor-positive (ER+; hazard ratio [HR], 1.24; 95% CI, 1.05-1.46; P = .01), but not in ER- disease (HR, 0.97; 95% CI, 0.83-1.14; P = .73), and significant interaction between race and ER status was observed (P = .03). There was no racial disparity in DRFS among patients with pathologic complete response (pCR) (log-rank P = .8). For patients without pCR, Black race was associated with worse DRFS in ER+ (HR, 1.67; 95% CI, 1.14-2.45; P = .01), but not in ER- disease (HR, 0.91; 95% CI, 0.65-1.28; P = .59). CONCLUSIONS: Black race was associated with significantly inferior DRFS in ER+ localized breast cancer treated with AC or NAC, but not in ER- disease. In the NAC group, racial disparity was also observed in patients with residual ER+ breast cancer at surgery, but not in those who had pCR. LAY SUMMARY: Black women with breast cancer have worse outcomes compared with White women. We investigated if this held true in the context of clinical trials that provide controlled treatment setting. Black women with cancer expressing estrogen receptors (ERs) had worse outcome than White women. If breast cancers did not express ERs, there was no racial disparity in outcome. We also observed racial disparity in women who received chemotherapy before their cancer was removed, but only if they had cancer expressing ERs and residual disease on completion of treatment. If the cancer disappeared with presurgical chemotherapy, there was no racial disparity.

Predictive Factors for Surgical Site Infections in Patients Undergoing Surgery for Breast Carcinoma.

INTRODUCTION: Operative interventions for breast cancer are generally classified as clean surgeries. Surgical site infections (SSIs), while rare, do occur. This study sought to identify risk factors for SSI, using the National Surgical Quality Improvement Program (NSQIP). METHODS: NSQIP's participant use data files (PUF) between 2012 and 2015 were examined. Female patients with invasive breast cancer who underwent surgery were identified through CPT and ICD9 codes. Non-SSI and SSI groups were compared and the statistical differences were addressed through propensity score weighting. Multivariate logistic regression testing was used to identify predictors of SSI. RESULTS: This study examined 30 544 lumpectomies and 23 494 mastectomies. SSI rate was 1126/54 038 patients (2.1%). In the weighted dataset, mastectomy, diabetes, smoking, COPD, ASA class-severe, BMI >35 kg/m2, and length of stay (LOS) >1 day were associated with an increased odds ratio (OR) of SSI. The OR for SSI was highest after mastectomy with reconstruction (OR 2.626, P < .001; 95% CI 2.073-3.325). Postoperative variables associated with an increased OR of SSIs included systemic infection, unplanned reoperation wound dehiscence, and renal failure. CONCLUSION: Mastectomy, diabetes, smoking, COPD, ASA class-severe, BMI >35 kg/m2, length of stay (LOS) >1 day are associated with an increased OR for SSIs following breast surgery.

The Contribution of Race to Breast Tumor Microenvironment Composition and Disease Progression.

Breast cancer is the second most commonly diagnosed cancer in American women following skin cancer. Despite overall decrease in breast cancer mortality due to advances in treatment and earlier screening, black patients continue to have 40% higher risk of breast cancer related death compared to white patients. This disparity in outcome persists even when controlled for access to care and stage at presentation and has been attributed to differences in tumor subtypes or gene expression profiles. There is emerging evidence that the tumor microenvironment (TME) may contribute to the racial disparities in outcome as well. Here, we provide a comprehensive review of current literature available regarding race-dependent differences in the TME. Notably, black patients tend to have a higher density of pro-tumorigenic immune cells (e.g., M2 macrophages, regulatory T cells) and microvasculature. Although immune cells are classically thought to be anti-tumorigenic, increase in M2 macrophages and angiogenesis may lead to a paradoxical increase in metastasis by forming doorways of tumor cell intravasation called tumor microenvironment of metastasis (TMEM). Furthermore, black patients also have higher serum levels of inflammatory cytokines, which provide a positive feedback loop in creating a pro-metastatic TME. Lastly, we propose that the higher density of immune cells and angiogenesis observed in the TME of black patients may be a result of evolutionary selection for a more robust immune response in patients of African geographic ancestry. Better understanding of race-dependent differences in the TME will aid in overcoming the racial disparity in breast cancer mortality.

Assessing Tumor Microenvironment of Metastasis Doorway-Mediated Vascular Permeability Associated with Cancer Cell Dissemination using Intravital Imaging and Fixed Tissue Analysis.

The most common cause of cancer related mortality is metastasis, a process that requires dissemination of cancer cells from the primary tumor to secondary sites. Recently, we established that cancer cell dissemination in primary breast cancer and at metastatic sites in the lung occurs only at doorways called Tumor MicroEnvironment of Metastasis (TMEM). TMEM doorway number is prognostic for distant recurrence of metastatic disease in breast cancer patients. TMEM doorways are composed of a cancer cell which over-expresses the actin regulatory protein Mena in direct contact with a perivascular, proangiogenic macrophage which expresses high levels of TIE2 and VEGF, where both of these cells are tightly bound to a blood vessel endothelial cell. Cancer cells can intravasate through TMEM doorways due to transient vascular permeability orchestrated by the joint activity of the TMEM-associated macrophage and the TMEM-associated Mena-expressing cancer cell. In this manuscript, we describe two methods for assessment of TMEM-mediated transient vascular permeability: intravital imaging and fixed tissue immunofluorescence. Although both methods have their advantages and disadvantages, combining the two may provide the most complete analyses of TMEM-mediated vascular permeability as well as microenvironmental prerequisites for TMEM function. Since the metastatic process in breast cancer, and possibly other types of cancer, involves cancer cell dissemination via TMEM doorways, it is essential to employ well established methods for the analysis of the TMEM doorway activity. The two methods described here provide a comprehensive approach to the analysis of TMEM doorway activity, either in naïve or pharmacologically treated animals, which is of paramount importance for pre-clinical trials of agents that prevent cancer cell dissemination via TMEM.

Black race and distant recurrence after neoadjuvant or adjuvant chemotherapy in breast cancer.

Black race compared to white race is associated with more advanced stage and biologically aggressive breast cancer. Consequently, black patients are more frequently treated with neoadjuvant chemotherapy (NAC) than white patients. However, it is unclear how distant recurrence-free survival (DRFS) of black patients treated with NAC, compares to DRFS of black patients treated with adjuvant chemotherapy (AC). We evaluated the association between race, distant recurrence, and type of chemotherapy (AC or NAC) in localized or locally advanced breast cancer. We evaluated DRFS in 807 patients, including 473 black, 252 white, 56 Hispanic, and 26 women of other or mixed race. The association between AC or NAC and DRFS was examined using multivariate Cox proportional hazard models that included race, age, stage, estrogen receptor (ER) and triple negative (TN) status. When the black and white subjects were pooled for the analysis the features associated with worse DRFS included stage III disease and age < 50 years, but not ER-negative disease, TN disease, the use of NAC, or black race. However, in the analysis stratified by race NAC was associated with worse DRFS compared to AC in black (HR 2.70; 95% CI 1.73-4.22; p < 0.0001), but not in white women (HR 1.29, 95% CI 0.56-2.95; p = 0.36). Black patients treated with NAC had worse DRFS than black patients treated with AC, or white patients treated with either NAC or AC. These findings need to be validated in a large-scale observational study and the effect of NAC on the breast cancer microenvironment in black women needs to be further evaluated.

Time-lapsed, large-volume, high-resolution intravital imaging for tissue-wide analysis of single cell dynamics.

Pathologists rely on microscopy to diagnose disease states in tissues and organs. They utilize both high-resolution, high-magnification images to interpret the staining and morphology of individual cells, as well as low-magnification overviews to give context and location to these cells. Intravital imaging is a powerful technique for studying cells and tissues in their native, live environment and can yield sub-cellular resolution images similar to those used by pathologists. However, technical limitations prevent the straightforward acquisition of low-magnification images during intravital imaging, and they are hence not typically captured. The serial acquisition, mosaicking, and stitching together of many high-resolution, high-magnification fields of view is a technique that overcomes these limitations in fixed and ex vivo tissues. The technique however, has not to date been widely applied to intravital imaging as movements caused by the living animal induce image distortions that are difficult to compensate for computationally. To address this, we have developed techniques for the stabilization of numerous tissues, including extremely compliant tissues, that have traditionally been extremely difficult to image. We present a novel combination of these stabilization techniques with mosaicked and stitched intravital imaging, resulting in a process we call Large-Volume High-Resolution Intravital Imaging (LVHR-IVI). The techniques we present are validated and make large volume intravital imaging accessible to any lab with a multiphoton microscope.

Neoadjuvant chemotherapy induces breast cancer metastasis through a TMEM-mediated mechanism.

Breast cancer cells disseminate through TIE2/MENACalc/MENAINV-dependent cancer cell intravasation sites, called tumor microenvironment of metastasis (TMEM), which are clinically validated as prognostic markers of metastasis in breast cancer patients. Using fixed tissue and intravital imaging of a PyMT murine model and patient-derived xenografts, we show that chemotherapy increases the density and activity of TMEM sites and Mena expression and promotes distant metastasis. Moreover, in the residual breast cancers of patients treated with neoadjuvant paclitaxel after doxorubicin plus cyclophosphamide, TMEM score and its mechanistically connected MENAINV isoform expression pattern were both increased, suggesting that chemotherapy, despite decreasing tumor size, increases the risk of metastatic dissemination. Chemotherapy-induced TMEM activity and cancer cell dissemination were reversed by either administration of the TIE2 inhibitor rebastinib or knockdown of the MENA gene. Our results indicate that TMEM score increases and MENA isoform expression pattern changes with chemotherapy and can be used in predicting prometastatic changes in response to chemotherapy. Furthermore, inhibitors of TMEM function may improve clinical benefits of chemotherapy in the neoadjuvant setting or in metastatic disease.

Loss of MEN1 activates DNMT1 implicating DNA hypermethylation as a driver of MEN1 tumorigenesis.

Multiple endocrine neoplasia type 1 (MEN1) syndrome results from mutations in the MEN1 gene and causes tumor formation via largely unknown mechanisms. Using a novel genome-wide methylation analysis, we studied tissues from MEN1-parathyroid tumors, Men1 knockout (KO) mice, and Men1 null mouse embryonic fibroblast (MEF) cell lines. We demonstrated that inactivation of menin (the protein product of MEN1) increases activity of DNA (cytosine-5)-methyltransferase 1 (DNMT1) by activating retinoblastoma-binding protein 5 (Rbbp5). The increased activity of DNMT1 mediates global DNA hypermethylation, which results in aberrant activation of the Wnt/ß-catenin signaling pathway through inactivation of Sox regulatory genes. Our study provides important insights into the role of menin in DNA methylation and its impact on the pathogenesis of MEN1 tumor development.

Environmental enrichment restores neurogenesis and rapid acquisition in aged rats.

Strategies combatting cognitive decline among the growing aging population are vital. We tested whether environmental enrichment could reverse age-impaired rapid spatial search strategy acquisition concomitantly with hippocampal neurogenesis in rats. Young (5-8 months) and aged (20-22 months) male Fischer 344 rats were pair-housed and exposed to environmental enrichment (n = 7 young, 9 aged) or housed individually (n = 7 young, 7 aged) for 10 weeks. After 5 weeks, hidden platform trials (5 blocks of 3 trials; 15 m inter-block interval), a probe trial, and then visible platform trials (5 blocks of 3 trials; 15 m inter-block interval) commenced in the water maze. One week after testing, rats were given 5 daily intraperitoneal bromodeoxyuridine (50 mg/kg) injections and perfused 4 weeks later to quantify neurogenesis. Although young rats outperformed aged rats, aged enriched rats outperformed aged individually housed rats on all behavioral measures. Neurogenesis decreased with age but enrichment enhanced new cell survival, regardless of age. The novel correlation between new neuron number and behavioral measures obtained in a rapid water maze task among aged rats, suggests that environmental enrichment increases their ability to rapidly acquire and flexibly use spatial information along with neurogenesis.