Corrigendum: Discovery of metastases in thyroid cancer and "benign metastasizing goiter": a historical note.

[This corrects the article DOI: 10.3389/fendo.2024.1354750.].

Discovery of metastases in thyroid cancer and "benign metastasizing goiter": a historical note.

At the beginning of the eighteenth century, most physicians recognized cancer as an aggressive process that gradually spreads, leading to cachexia and death. Thyroid malignancies had long been underestimated because the majority of the population of West Europe suffered from diffuse goiters that masked malignant processes in the neck. Moreover, the life expectancy at that time was very low (about 37-40 years), so the majority of people died of other causes before metastatic thyroid cancer could develop and manifest. Nevertheless, in 1817, French dermatologist Jean Louis Alibert described the first case of a malignant tumor involving the thyroid gland. From the 1820s the number of case reports describing thyroid cancer increased. Even though Jean Claude Recamier described metastases in 1829, secondary lesions on various organs in patients with thyroid malignancies were not themselves considered malignant until 1876.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing.

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Impaired Glucose Metabolism, Anti-Diabetes Medications, and Risk of Thyroid Cancer.

The prevalence of obesity is progressively increasing along with the potential high risk for insulin resistance and development of type 2 diabetes mellitus. Obesity is associated with increased risk of many malignancies, and hyperinsulinemia has been proposed to be a link between obesity and cancer development. The incidence of thyroid cancer is also increasing, making this cancer the most common endocrine malignancy. There is some evidence of associations between obesity, insulin resistance and/or diabetes with thyroid proliferative disorders, including thyroid cancer. However, the etiology of such an association has not been fully elucidated. The goal of the present work is to review the current knowledge on crosstalk between thyroid and glucose metabolic pathways and the effects of obesity, insulin resistance, diabetes, and anti-hyperglycemic medications on the risk of thyroid cancer development.

Capecitabine and stereotactic radiation in the management of breast cancer brain metastases.

BACKGROUND: Little is known about the safety and efficacy of concurrent capecitabine and stereotactic radiotherapy in the setting of breast cancer brain metastases (BCBM). METHODS: Twenty-three patients with BCBM underwent 31 stereotactic sessions to 90 lesions from 2005 to 2019 with receipt of capecitabine. The Kaplan-Meier method was used to calculate overall survival (OS), local control (LC), and distant intracranial control (DIC) from the date of stereotactic radiation. Imaging was independently reviewed by a neuro-radiologist. RESULTS: Median follow-up from stereotactic radiation was 9.2 months. Receptor types of patients treated included triple negative (n = 7), hormone receptor (HR)+/HER2- (n = 7), HR+/HER2+ (n = 6), and HR-/HER2+ (n = 3). Fourteen patients had stage IV disease prior to BCBM diagnosis. The median number of brain metastases treated per patient was 3 (1 to 12). The median dose of stereotactic radiosurgery (SRS) was 21 Gy (range: 15-24 Gy) treated in a single fraction and for lesions treated with fractionated stereotactic radiation therapy (FSRT) 25 Gy (24-30 Gy) in a median of 5 fractions (range: 3-5). Of the 31 stereotactic sessions, 71% occurred within 1 month of capecitabine. No increased toxicity was noted in our series with no cases of radionecrosis. The 1-year OS, LC, and DIC were 46, 88, and 30%, respectively. CONCLUSIONS: In our single institution experience, we demonstrate stereotactic radiation and capecitabine to be a safe treatment for patients with BCBM with adequate LC. Further study is needed to determine the potential synergy between stereotactic radiation and capecitabine in the management of BCBM.

Trastuzumab Emtansine (T-DM1) and stereotactic radiation in the management of HER2+ breast cancer brain metastases.

BACKGROUND: Due to recent concerns about the toxicity of trastuzumab emtansine (T-DM1) with stereotactic radiation, we assessed our institutional outcomes treating HER2-positive breast cancer brain metastases (BCBM) with T-DM1 and stereotactic radiation. METHODS: This is a single institution series of 16 patients with HER2-positive breast cancer who underwent 18 stereotactic sessions to 40 BCBM from 2013 to 2019 with T-DM1 delivered within 6 months. The Kaplan-Meier method was used to calculate overall survival (OS), local control (LC), distant intracranial control (DIC), and systemic progression-free survival (sPFS) from the date of SRS. A neuro-radiologist independently reviewed follow-up imaging. RESULTS: One patient had invasive lobular carcinoma, and 15 patients had invasive ductal carcinoma. All cases were HER2-positive, while 10 were hormone receptor (HR) positive. Twenty-four lesions were treated with stereotactic radiosurgery (SRS) to a median dose of 21 Gy (14-24 Gy). Sixteen lesions were treated with fractionated stereotactic radiation (FSRT) with a median dose of 25 Gy (20-30Gy) delivered in 3 to 5 fractions. Stereotactic radiation was delivered concurrently with T-DM1 in 19 lesions (48%). Median follow up time was 13.2 months from stereotactic radiation. The 1-year LC, DIC, sPFS, and OS were 75, 50, 30, and 67%, respectively. There was 1 case of leptomeningeal progression and 1 case (3%) of symptomatic radionecrosis. CONCLUSIONS: We demonstrate that stereotactic radiation and T-DM1 is well-tolerated and effective for patients with HER2-positive BCBM. An increased risk for symptomatic radiation necrosis was not noted in our series.

Thyroid Hormone Effects on Glucose Disposal in Patients With Insulin Receptor Mutations.

CONTEXT: Patients with mutations of the insulin receptor gene (INSR) have extreme insulin resistance and are at risk for early morbidity and mortality from diabetes complications. A case report suggested that thyroid hormone could improve glycemia in INSR mutation in part by increasing brown adipose tissue (BAT) activity and volume. OBJECTIVE: To determine if thyroid hormone increases tissue glucose uptake and improves hyperglycemia in INSR mutation. DESIGN: Single-arm, open-label study of liothyronine. SETTING: National Institutes of Health. PARTICIPANTS: Patients with homozygous (n = 5) or heterozygous (n = 2) INSR mutation. INTERVENTION: Liothyronine every 8 hours for 2 weeks (n = 7); additional 6 months' treatment in those with hemoglobin A1c (HbA1c) > 7% (n = 4). OUTCOMES: Whole-body glucose uptake by isotopic tracers; tissue glucose uptake in muscle, white adipose tissue (WAT) and BAT by dynamic [18F] fluorodeoxyglucose positron emission tomography/computed tomography; HbA1c. RESULTS: There was no change in whole-body, muscle, or WAT glucose uptake from baseline to 2 weeks of liothyronine. After 6 months, there was no change in HbA1c (8.3 ± 1.2 vs 9.1 ± 3.0%, P = 0.27), but there was increased whole-body glucose disposal (22.8 ± 4.9 vs 30.1 ± 10.0 µmol/kg lean body mass/min, P = 0.02), and muscle (0.7 ± 0.1 vs 2.0 ± 0.2 µmol/min/100 mL, P < 0.0001) and WAT glucose uptake (1.2 ± 0.2 vs 2.2 ± 0.3 µmol/min/100 mL, P < 0.0001). BAT glucose uptake could not be quantified because of small volume. There were no signs or symptoms of hyperthyroidism. CONCLUSION: Liothyronine administered at well-tolerated doses did not improve HbA1c. However, the observed increases in muscle and WAT glucose uptake support the proposed mechanism that liothyronine increases tissue glucose uptake. More selective agents may be effective at increasing tissue glucose uptake without thyroid hormone-related systemic toxicity.Clinical Trial Registration Number: NCT02457897; https://clinicaltrials.gov/ct2/show/NCT02457897.

Percutaneous Vertebroplasty: A History of Procedure, Technology, Culture, Specialty, and Economics.

Percutaneous vertebroplasty (VP) progressed from a virtually unknown procedure to one performed on hundreds of thousands of patients annually. The development of VP provides a historically exciting case study into a rapidly adopted procedure. VP was the synthesis of information gained from spinal biopsy developments, the inception of biomaterials used in medicine, and the unique health care climate in France during the 1980s. It was designed as a revolutionary technique to treat vertebral body fractures with minimal side effects and was rapidly adopted and marketed in the United States. The impact of percutaneous vertebroplasty on spine surgery was profound.

Percutaneous Vertebral Body Augmentations: The State of Art.

Osteoporotic compression fractures of the vertebral body can result in pain and long-term morbidity, including spinal deformity, with increased risk of mortality resulting from associated complications. Conservative management includes opioids and other analgesics, bed rest, and a back brace. For patients with severe and disabling pain, vertebral augmentation (vertebroplasty and kyphoplasty) is often considered, with these procedures endorsed by multiple professional societies, and provides immediate structural support, and stabilizes and reinforces the weakened bone structure. The purpose of this article is to review the vertebral biomechanics, indications and contraindications, and techniques of performing successful vertebral augmentation.

Medullary Thyroid Carcinoma: An Update on Imaging.

Medullary thyroid carcinoma (MTC), arising from the parafollicular C cells of the thyroid, accounts for 1-2% of thyroid cancers. MTC is frequently aggressive and metastasizes to cervical and mediastinal lymph nodes, lungs, liver, and bones. Although a number of new imaging modalities for directing the management of oncologic patients evolved over the last two decades, the clinical application of these novel techniques is limited in MTC. In this article, we review the biology and molecular aspects of MTC as an important background for the use of current imaging modalities and approaches for this tumor. We discuss the modern and currently available imaging techniques-advanced magnetic resonance imaging (MRI)-based techniques such as whole-body MRI, dynamic contrast-enhanced (DCE) technique, diffusion-weighted imaging (DWI), positron emission tomography/computed tomography (PET/CT) with 18F-FDOPA and 18F-FDG, and integrated positron emission tomography/magnetic resonance (PET/MR) hybrid imaging-for primary as well as metastatic MTC tumor, including its metastatic spread to lymph nodes and the most common sites of distant metastases: lungs, liver, and bones.

Thyroid Abnormalities in Patients With Extreme Insulin Resistance Syndromes.

CONTEXT: Insulin and leptin may increase growth and proliferation of thyroid cells, underlying an association between type 2 diabetes and papillary thyroid cancer (PTC). Patients with extreme insulin resistance due to lipodystrophy or insulin receptor mutations (INSR) are treated with high-dose insulin and recombinant leptin (metreleptin), which may increase the risk of thyroid neoplasia. OBJECTIVE: The aim of this study was to analyze thyroid structural abnormalities in patients with lipodystrophy and INSR mutations and to assess whether insulin, IGF-1, and metreleptin therapy contribute to the thyroid growth and neoplasia in this population. DESIGN: Thyroid ultrasound characteristics were analyzed in 81 patients with lipodystrophy and 11 with INSR (5 homozygous; 6 heterozygous). Sixty patients were taking metreleptin. RESULTS: The prevalence of thyroid nodules in children with extreme insulin resistance (5 of 30, 16.7%) was significantly higher than published prevalence for children (64 of 3202; 2%), with no difference between lipodystrophy and INSR. Body surface area-adjusted thyroid volume was larger in INSR homozygotes vs heterozygotes or lipodystrophy (10.4 ± 5.1, 3.9 ± 1.5, and 6.2 ± 3.4 cm2, respectively. Three patients with lipodystrophy and one INSR heterozygote had PTC. There were no differences in thyroid ultrasound features in patients treated vs not treated with metreleptin. CONCLUSION: Children with extreme insulin resistance had a high prevalence of thyroid nodules, which were not associated with metreleptin treatment. Patients with homozygous INSR mutation had thyromegaly, which may be a novel phenotypic feature of this disease. Further studies are needed to determine the etiology of thyroid abnormalities in patients with extreme insulin resistance.

Fibrous dysplasia for radiologists: beyond ground glass bone matrix.

Fibrous dysplasia (FD) is a congenital disorder arising from sporadic mutation of the α-subunit of the Gs stimulatory protein. Osseous changes are characterised by the replacement and distortion of normal bone with poorly organised, structurally unsound, fibrous tissue. The disease process may be localised to a single or multiple bones. In McCune-Albright syndrome (MAS), fibrous dysplasia is associated with hyperfunction of endocrine organs and overproduction of melanin in the skin, while Mazabraud syndrome FD is associated with intramuscular myxomas. In radiology, FD is very often automatically associated with the term "ground glass matrix". However, FD is a complex disease, and knowledge of its unique pathogenesis and course are crucial to understanding imaging findings and potential complications. This article aims to not only summarise the spectrum of radiological findings of osseous and extra-osseous abnormalities associated with FD but also to highlight the pathological base of the disease evolution, corresponding imaging changes and complications based on the disease distribution. We also have provided current recommendations for clinical management and follow-up of patients with FD. TEACHING POINTS: • FD is often a part of complex disease, involving not only bone but also multiple other organs. • FD lesions are characterised by age-related histological, radiographical and clinical transformations. • Radiologists play a crucial role in the identification of osseous complications associated with FD. • The craniofacial form of the disease is the most common type of FD and the most difficult form to manage. • Patients with McCune-Albright syndrome may have different extra-skeletal abnormalities, which often require follow-up.

ABCs of the degenerative spine.

Degenerative changes in the spine have high medical and socioeconomic significance. Imaging of the degenerative spine is a frequent challenge in radiology. The pathogenesis of this degenerative process represents a biomechanically related continuum of alterations, which can be identified with different imaging modalities. The aim of this article is to review radiological findings involving the intervertebral discs, end plates, bone marrow changes, facet joints and the spinal canal in relation to the pathogenesis of degenerative changes in the spine. Findings are described in association with the clinical symptoms they may cause, with a brief review of the possible treatment options. The article provides an illustrated review on the topic for radiology residents. TEACHING POINTS: • The adjacent vertebrae, intervertebral disc, ligaments and facet joints constitute a spinal unit. • Degenerative change is a response to insults, such as mechanical or metabolic injury. • Spine degeneration is a biomechanically related continuum of alterations evolving over time.

Focal Hepatic Glycogenosis in a Patient With Uncontrolled Diabetes Mellitus Type 1.

Hepatomegaly and elevated liver enzymes in patients with diabetes are commonly associated with fatty liver disease. However, physicians often forget about another intrinsic substance that can cause a similar clinical picture-glycogen. Liver stores approximately one third of the total body glycogen and is responsible for blood glucose homeostasis. Excessive hepatocellular glycogen accumulation occurs not only in congenital glycogen storage diseases, but also in acquired conditions associated with hyperglycemic-hyperinsulinemic states such as uncontrolled diabetes mellitus, high-dose corticosteroid use, and dumping syndrome. All reported cases of acquired abnormal glycogen deposition described a diffuse form of hepatic glycogenosis with the entire liver involved in the accumulating process. To our knowledge, this is the first reported case of abnormal focal glycogen deposition in a patient with diabetes mellitus type 1 with imaging and pathologic correlation. Awareness of the imaging appearance of focal glycogen deposition can help to distinguish it from other pathologic conditions.

Hyaluronic acid scaffold has a neuroprotective effect in hemisection spinal cord injury.

OBJECTIVE Spinal cord injury occurs in 2 phases. The initial trauma is followed by inflammation that leads to fibrous scar tissue, glial scarring, and cavity formation. Scarring causes further axon death around and above the injury. A reduction in secondary injury could lead to functional improvement. In this study, hyaluronic acid (HA) hydrogels were implanted into the gap formed in the hemisected spinal cord of Sprague-Dawley rats in an attempt to attenuate damage and regenerate tissue. METHODS A T-10 hemisection spinal cord injury was created in adult male Sprague-Dawley rats; the rats were assigned to a sham, control (phosphate-buffered saline), or HA hydrogel-treated group. One cohort of 23 animals was followed for 12 weeks and underwent weekly behavioral assessments. At 12 weeks, retrograde tracing was performed by injecting Fluoro-Gold in the left L-2 gray matter. At 14 weeks, the animals were killed. The volume of the lesion and the number of cells labeled from retrograde tracing were calculated. Animals in a separate cohort were killed at 8 or 16 weeks and perfused for immunohistochemical analysis and transmission electron microscopy. Samples were stained using H & E, neurofilament stain (neurons and axons), silver stain (disrupted axons), glial fibrillary acidic protein stain (astrocytes), and Iba1 stain (mononuclear cells). RESULTS The lesions were significantly smaller in size and there were more retrograde-labeled cells in the red nuclei of the HA hydrogel-treated rats than in those of the controls; however, the behavioral assessments revealed no differences between the groups. The immunohistochemical analyses revealed decreased fibrous scarring and increased retention of organized intact axonal tissue in the HA hydrogel-treated group. There was a decreased presence of inflammatory cells in the HA hydrogel-treated group. No axonal or neuronal regeneration was observed. CONCLUSIONS The results of these experiments show that HA hydrogel had a neuroprotective effect on the spinal cord by decreasing the magnitude of secondary injury after a lacerating spinal cord injury. Although regeneration and behavioral improvement were not observed, the reduction in disorganized scar tissue and the retention of neurons near and above the lesion are important for future regenerative efforts. In addition, this gel would be useful as the base substrate in the development of a more complex scaffold.

Two bullets to the head and an early winter: fate permits Kutuzov to defeat Napoleon at Moscow.

General Mikhail Kutuzov (circa 1745-1813) brilliantly repelled Napoleon's invasion of Russia. Honored as a national hero and a savior of Russia, Kutuzov has a unique medical story. He was shot in the head twice while fighting the Turks (1774 and 1788) and survived the serious injuries seemingly against all odds. The first bullet "ran through the head from one temple to the other behind both eyes." The second bullet entered the cheek, destroyed upper teeth, traveled through the head, and exited the occiput. Massot, a French surgeon with the Russian army, wrote after treating Kutuzov's seemingly two mortal wounds: "It must be believed that fate appoints Kutuzov to something great, because he was still alive after two injuries, a death sentence by all the rules of medical science." Aided by Massot's expert surgical technique, Kutuzov lived to become intimately engaged in events that altered world history. His health did, however, suffer significant effects due to the bullet wounds. In 1812, as Napoleon's Grande Armée approached, Kutuzov realized he could not confront Napoleon and he strategically retreated from Moscow, submitting the French to the harsh winter and Russian cavalry. Napoleon's devastated army retreated to Paris, and Kutuzov became the personification of Russian spirit and character. Kutuzov's survival of two nearly mortal head wounds created the legends, additional mystery, and drama surrounding him, not the least astonishing of which was the skilled neurosurgical care that probably saved his life.

Spinal metastases due to thyroid carcinoma: an analysis of 202 patients.

BACKGROUND: Spinal metastases (SMs) due to thyroid cancer (TC) are associated with significantly reduced quality of life. The goal of this study is to analyze the clinical manifestations, presentation, and treatments of TC SMs, and to describe specific features of SMs associated with different TC types. PATIENTS AND METHODS: A retrospective analysis of 202 TC SM patients treated at Medstar Washington Hospital Center (37) and collected from the literature (165) was performed. RESULTS: The mean age of patients with SMs was 56.9±14.7 years, and the female-to-male ratio was 2.1:1. Of all patients, 29% (28% of follicular thyroid cancer [FTC] and 37% of papillary thyroid cancer [PTC]) had SMs only. Twenty-nine percent of all patients and 54% of patients with single-site SMs had neither bone non-SMs nor solid organ metastases at the time of presentation. Thirty-five percent of patients had SMs as an initial presentation of TC. TC patients presenting with SMs had a lower rate of other bone and visceral involvement compared with patients whose SMs were diagnosed at the time of thyroid surgery or during follow-up (p<0.05). SMs were more often the initial manifestation of FTC (41% vs. 24%), while PTC SMs were more commonly diagnosed after TC diagnosis (76% vs. 59%; p<0.05). PTC SMs were more frequently diagnosed as synchronous (63% vs. 36% in FTC) versus FTC SMs that developed as metachronous metastases (64% vs. 37% in PTC; p<0.01). All FTC SMs developed within 82 (0-372) months and all PTC SMs within 35 (0-144) months (p<0.01). In FTC SMs as TC manifestation, solid organ metastases involvement was less common than in FTC SMs that were found after TC diagnosis (34% vs. 67%; p<0.01); multisite FTC SMs compared to solitary FTC SMs were associated with the development of other bone nonspinal metastases (82% vs. 30%; p<0.01) and solitary organ metastases (65% vs. 41%; p<0.01). These correlations were not observed in PTC SMs. FTC patients often had neural structure compression (myelopathy/radiculopathy; 72% vs. 36% in PTC), while PTC patients frequently were asymptomatic (38% vs. 5% in FTC; p<0.01). FTC SMs more commonly were (131)I-avid (p<0.01). FTC patients required surgery more frequently (72% vs. 55% in PTC; p<0.05). CONCLUSIONS: Our study reveals that a significant part of TC SMs patients have solitary spinal involvement at the time of presentation and may be considered for aggressive treatment with the intention to improve quality of life and survival. FTC SMs and PTC SMs appear to have distinct presentations, behavior, and treatment modalities, and should be categorized separately for treatment and follow-up planning.

Current treatment modalities for spinal metastases secondary to thyroid carcinoma.

BACKGROUND: The spine is the most common site of bone metastases due to thyroid cancer, which develop in more than 3% of patients with well-differentiated thyroid cancer. Nearly half of patients with bone metastases from thyroid cancer develop vertebral metastases. Spinal metastases are associated with significantly reduced quality of life due to pain, neurological deficit, and increased mortality. SUMMARY: Treatment options for patients with thyroid spinal metastases include radioiodine therapy, pharmacologic therapy, and surgical treatments, with recent advances in radiosurgery and minimally invasive spinal surgery as well. Therapeutic interventions require a multidisciplinary approach and aim to control pain, preserve or improve neurologic function, optimize local tumor control, and improve quality of life. We have proposed a three-tiered approach to the management and practical algorithms for patients with spinal metastases from thyroid carcinoma. CONCLUSIONS: The introduction of novel and improved techniques for the treatment of spinal metastases has created the opportunity to significantly improve control of metastatic tumor growth and the quality of life for the patients with spinal metastases from thyroid cancer. In order for these options to be effectively used, a multidisciplinary approach must be applied in the management of the patients with thyroid spinal metastases.

Monocyte-derived cells of the brain and malignant gliomas: the double face of Janus.

OBJECTIVE: Monocyte-derived cells of the brain (MDCB) are a diverse group of functional immune cells that are also highly abundant in gliomas. There is growing evidence that MDCB play essential roles in the pathogenesis of gliomas. The aim of this review was to collate and systematize contemporary knowledge about these cells as they relate to glioma progression and antiglioblastoma therapeutic modalities with a view toward improved effectiveness of therapy. METHODS: We reviewed relevant studies to construct a summary of different MDCB subpopulations in steady state and in malignant gliomas and discuss their role in the development of malignant gliomas and potential future therapies. RESULTS: Current studies suggest that MDCB subsets display different phenotypes and differentiation potentials depending on their milieu in the brain and exposure to tumoral influences. MDCB possess specific and unique functions, including those that are protumoral and those that are antitumoral. CONCLUSIONS: Elucidating the role of mononuclear-derived cells associated with gliomas is crucial in designing novel immunotherapy strategies. Much progress is needed to characterize markers to identify cell subsets and their specific regulatory roles. Investigation of MDCB can be clinically relevant. Specific MDCB populations potentially can be used for glioma therapy as a target or as cell vehicles that might deliver cytotoxic substances or processes to the glioma microenvironment.

Monocyte galactose/N-acetylgalactosamine-specific C-type lectin receptor stimulant immunotherapy of an experimental glioma. Part 1: stimulatory effects on blood monocytes and monocyte-derived cells of the brain.

OBJECTIVES: Immunotherapy with immunostimulants is an attractive therapy against gliomas. C-type lectin receptors specific for galactose/N-acetylgalactosamine (GCLR) regulate cellular differentiation, recognition, and trafficking of monocyte-derived cells. A peptide mimetic of GCLR ligands (GCLRP) was used to activate blood monocytes and populations of myeloid-derived cells against a murine glioblastoma. METHODS: The ability of GCLRP to stimulate phagocytosis by human microglia and monocyte-derived cells of the brain (MDCB) isolated from a human glioblastoma was initially assessed in vitro. Induction of activation markers on blood monocytes was assayed by flow cytometry after administration of GCLRP to naive mice. C57BL/6 mice underwent stereotactic intracranial implantation of GL261 glioma cells and were randomized for tumor size by magnetic resonance imaging, which was also used to assess increase in tumor size. Brain tumor tissues were analyzed using flow cytometry, histology, and enzyme-linked immunosorbent assay with respect to tumor, peritumoral area, and contralateral hemisphere regions. RESULTS: GCLRP exhibited strong stimulatory effect on MDCBs and blood monocytes in vitro and in vivo. GCLRP was associated with an increased percentage of precursors of dendritic cells in the blood (P = 0.003), which differentiated into patrolling macrophages in tumoral (P = 0.001) and peritumoral areas (P = 0.04), rather than into dendritic cells, as in control animals. Treatment with GCLRP did not result in a significant change in survival of mice bearing a tumor. CONCLUSIONS: In vitro and in vivo activation of monocytes was achieved by administration of GCLR to mice. GCLRP-activated blood monocytes were recruited to the brain and exhibited specific phenotypes corresponding with tumor region (glioma, peritumoral zone, and contralateral glioma-free hemisphere). GCLRP treatment alone was associated with increased glioma mass as the result of the infiltration of phagocytic cells. Regional specificity for MDCB may have significant tumor treatment implications.