Patterns of metastasis and natural courses of breast carcinoma

Evolution of Metastasis Study Models toward Metastasis-On-A-Chip: The Ultimate Model?

For decades, several attempts have been made to obtain a mimetic model for the study of metastasis, the reason of most of deaths caused by cancer, in order to solve the unknown phenomena surrounding this disease. To better understand this cellular dissemination process, more realistic models are needed that are capable of faithfully recreating the entire and essential tumor microenvironment (TME). Thus, new tools known as tumor-on-a-chip and metastasis-on-a-chip have been recently proposed. These tools incorporate microfluidic systems and small culture chambers where TME can be faithfully modeled thanks to 3D bioprinting. In this work, a literature review has been developed about the different phases of metastasis, the remaining unknowns and the use of new models to study this disease. The aim is to provide a global vision of the current panorama and the great potential that these systems have for in vitro translational research on the molecular basis of the pathology. In addition, these models will allow progress toward a personalized medicine, generating chips from patient samples that mimic the original tumor and the metastatic process to perform a precise pharmacological screening by establishing the most appropriate treatment protocol.

Nutraceuticals and Metastasis Development

Nutrigenomics is a discipline that studies the effects of various dietary components on gene expression and molecular mechanisms via “omics” technologies. Many studies are focused on revealing the pathways of the anticancer properties of various nutraceuticals. However, it has been shown that metastasis, a multifactorial disease that develops from primary tumors in cascades, is responsible for almost 90% of cancer deaths. Regrettably, the effects of consumption of different nutraceuticals on metastasis development have not yet been sufficiently explored. A few studies on the subject have revealed the promotional effects of some nutraceuticals on metastasis development. Additionally, it has been shown that certain compounds can have beneficial effects on reduction of the primary tumor, but afterwards promote the spread of metastases. Therefore, in this review we discuss results published in the past five years focused on the effects of different nutraceuticals on metastasis development.

Tumour-to-tumour metastasis: breast carcinoma to an olfactory neuroblastoma

Tumour-to-tumour metastasis is a rare phenomenon. It occurs when a primary tumour is a recipient of a separate tumour within the same individual. We present a case of a 66-year-old woman with known breast cancer who presented with one-sided nasal symptoms. Examination and imaging revealed a unilateral polyp arising from the skull base. She underwent endoscopic polypectomy with the histology demonstrating tumour-to-tumour metastasis from a breast carcinoma to an olfactory neuroblastoma, a rare sinonasal tumour. Clinicians should be cautious of distant metastases in any patient presenting with head and neck symptoms and a known primary tumour. This is the first documented case of this type.

Incidental abdominal lymph node metastases from a known breast cancer in resected specimen of invasive pancreatic ductal adenocarcinoma: report of a case

Breast cancer is known to metastasize to all organs of the body. However, abdominal lymph node metastases from breast cancer are extremely rare. We herein report a resected case of an invasive pancreatic ductal adenocarcinoma (PDAC) in which abdominal lymph node metastases from breast cancer were diagnosed. A 54-year-old woman was pointed out to have a tumor in the pancreatic tail with dilatation of the distal pancreatic duct. She had undergone partial mastectomy for left breast cancer at the age of 51 years and had undergone partial liver resection for liver metastasis in the segment 3/4 6 months earlier. Computed tomography revealed a low-density tumor in the pancreatic tail with dilated distal main pancreatic duct. Magnetic resonance imaging (MRI) exhibited a high-intensity tumor in the pancreatic tail in diffusion-weighted images. With a diagnosis of pancreatic cancer, distal pancreatectomy and splenectomy with lymph nodes dissection was performed. Lymph node metastases along the splenic artery were pathologically similar to PDAC. However, lymph node metastases along the left gastric artery, common hepatic artery, celiac axis, and superior mesenteric artery were pathologically similar to breast cancer. Immunohistochemistry staining of abdominal lymph nodes with GATA-3 was positive, which strongly suggested metastatic breast cancer. Although she received chemotherapy with S-1 for breast cancer and PDAC for 4 months, MRI showed multiple liver metastases derived from breast cancer. Finally, she died 12 months after operation.

Metastasis Organotropism: Redefining the Congenial Soil

Metastasis is the most devastating stage of cancer progression and causes the majority of cancer-related deaths. Clinical observations suggest that most cancers metastasize to specific organs, a process known as "organotropism." Elucidating the underlying mechanisms may help identify targets and treatment strategies to benefit patients. This review summarizes recent findings on tumor-intrinsic properties and their interaction with unique features of host organs, which together determine organ-specific metastatic behaviors. Emerging insights related to the roles of metabolic changes, the immune landscapes of target organs, and variation in epithelial-mesenchymal transitions open avenues for future studies of metastasis organotropism.

Comparison between CEA, TPA, CA 15/3 and Hydroxyproline, Alkaline Phosphatase, Whole Body Retention of 99mTc MDP in the follow-up of Bone Metastases in Breast Cancer

The development of bone metastases in cancer can be monitored easily using three markers: 24 h urinary hydroxyproline excretion (HOP) (an index of osteoclastic activity), serum alkaline phosphatase (Alk.Ph.) (an index of osteoblastic activity) and 24 h whole body retention of 99mTc-methylene diphosphonate (WBR%) (an index of bone turnover). To evaluate the effectiveness of this group of bone tumor markers in breast cancer we compared it with the following group of three markers which are commonly used in the monitoring of breast cancer and in the follow-up of advanced disease with or without bone metastases: carcinoembryonic antigen (CEA), tissue polypeptide antigen (TPA) and breast carcinoma antigen (CA 15/3).

In 48 patients with bone metastases CEA, TPA and CA 15/3 were shown to be sensitive (79%, 85%, 90% respectively), while HOP, Alk.Ph. and WBR%, which are commonly accepted as reliable markers of bone activity, showed a lower sensitivity (67%, 46%, 75% respectively).

These results may be explained by the lack of osteoclastic or osteoblastic (or both) activity at the time of diagnosis. This explanation is supported by the fact that the bone markers HOP, Alk.Ph. and WBR% were found to be more sensitive than the others in the subsequent follow-up study.

We conclude that in our study, CEA, TPA and CA 15/3 are at first more sensitive than Alk. Ph., HOP and WBR% but during the follow-up Alk.Ph., HOP and WBR% are possibly both more specific and more sensitive

Inflammatory cytokine IL-8/CXCL8 promotes tumour escape from hepatocyte-induced dormancy

Background:

Breast cancers can recur after a long latency period following ‘successful’ primary treatments. Chronic inflammation significantly correlates with reduced diseased-free survival in breast cancer patients and could be a point of intervention to prevent recurrence. Liver is among the main sites of breast cancer recurrence. Thus, we hypothesise that inflammatory signals from hepatic stellate cells, the major inflammatory regulators in the sinusoid, could stimulate dormant cancer cells to emerge.

Methods:

We utilise in vitro co-culture of breast cancer cells with stellate cells and an ex vivo 3D human liver micro-physiologic system to identify stellate cells-derived factors that mediate tumour emergence.

Results:

Activated, but not quiescent, hepatic stellate cells secreted soluble factors to induce the proliferation of MCF7 and MDA-MB231 cancer cells. IL-8 and MCP-1 were highly secreted by the activated stellate cells and primary human non-parenchymal cells. IL-8 significantly reduced serum-starvation growth arrest on MDA-MB231 cells in vitro and increased cancer proliferation ex vivo. Blocking IL-8Rb/CXCR2 reduced IL-8-induced cancer growth and proliferation.

Conclusions:

Activated stellate cells can induce breast cancer emergence from dormancy in the liver by secreting inflammatory cytokines. Preventing liver inflammation or disrupting the subsequent key cytokines may prevent metastatic outgrowth.

Cancer metastasis - tricks of the trade

Decades of cancer research have unraveled genetic, epigenetic and molecular pathways leading to plausible therapeutic targets; many of which hold great promise in improving clinical outcomes. Metastatic tumors become evident early on and are one of the major causes of cancer-related fatalities worldwide. This review depicts the sequential events of cancer metastasis. Genetic and epigenetic heterogeneity influences local tumor cell invasion, intravasation, survival in circulation, extravasation and colonization to distant sites. Each sequential event is associated with heterogeneous tumor microenvironment, gain of competence, unique population of cancer stem cells (CSCs), circulatory pathway, compatible niche and immune system support. A tight regulation of metastasis-promoting mechanisms and, in parallel, evading inhibitory mechanisms contribute to the severity and site of metastasis. A comprehensive understanding of tumor cell fate as an individual entity, as well as in combination with different promoting factors and associated molecular mechanisms, is anticipated in the coming years. This will enable scientists to depict design strategies for targeted cancer therapies.

A Pathway to Personalizing Therapy for Metastases Using Liver-on-a-Chip Platforms

Metastasis accounts for most cancer-related deaths. The majority of solid cancers, including those of the breast, colorectum, prostate and skin, metastasize at significant levels to the liver due to its hemodynamic as well as tumor permissive microenvironmental properties. As this occurs prior to detection and treatment of the primary tumor, we need to target liver metastases to improve patients' outcomes. Animal models, while proven to be useful in mechanistic studies, do not represent the heterogeneity of human population especially in drug metabolism lack proper human cell-cell interactions, and this gap between animals and humans results in costly and inefficient drug discovery. This underscores the need to accurately model the human liver for disease studies and drug development. Further, the occurrence of liver metastases is influenced by the primary tumor type, sex and race; thus, modeling these specific settings will facilitate the development of personalized/targeted medicine for each specific group. We have adapted such all-human 3D ex vivo hepatic microphysiological system (MPS) (a.k.a. liver-on-a-chip) to investigate human micrometastases. This review focuses on the sources of liver resident cells, especially the iPS cell-derived hepatocytes, and examines some of the advantages and disadvantages of these sources. In addition, this review also examines other potential challenges and limitations in modeling human liver.

The Great Mimicker: Metastatic Breast Carcinoma to the Head and Neck with Emphasis on Unusual Clinical and Pathologic Features

Distant metastases are relatively common in breast cancer, but spread to the head and neck region is uncommon and can be diagnostically challenging. Pathology databases of two academic hospitals were searched for patients. The diagnoses were by morphologic comparison with the primary breast specimen (when available) or through the use of immunohistochemical stains characteristic of breast carcinoma (cytokeratin 7, mammaglobin, GCDFP15, and/or GATA3 positive-excluding new primary tumors at the respective head and neck sites). Of the 25 patients identified, only 22 (88.0 %) had a known history of breast carcinoma. Time from primary diagnosis to head and neck metastasis was highly variable, ranging from 1 to 33 years (mean = 10.9 years). The most common locations were neck lymph nodes (8 cases), orbital soft tissue (5), oral cavity (3), skull base (3), mastoid sinus (2), nasal cavity (1), palatine tonsil (1), and facial skin (1). Clinical presentations were highly variable, ranging from cranial nerve palsies without a mass lesion to oral cavity erythema and swelling to bone pain. Histologically, two cases showed mucosal (or skin)-based mass lesions with associated pagetoid spread in the adjacent epithelium, a feature normally associated with primary carcinomas. Three tumors were misdiagnosed pathologically as new head and neck primary tumors. This series demonstrates the extreme variability in clinical and pathologic features of breast cancer metastatic to the head and neck, including long time intervals to metastasis.

Intrinsic and extrinsic flaws of the nomogram predicting bone-only metastasis in women with early breast cancer: An external validation study

BACKGROUND

The recently developed MDACC nomogram purports to predict the risk of bone-only metastasis in women with early breast carcinoma based on five clinical and pathological characteristics. We set out to externally validate and assess its robustness using a tertiary breast cancer centre database.

METHODS

All consecutive women treated for early breast cancer in our centre between January 1989 and December 2013 and who had all the nomogram variables documented were eligible for analysis.

RESULTS

We identified 1255 eligible women for external validation analysis. The median follow-up was 54 months (range: 1-312) and time to initial metastasis 20 months (range: 1-80). The correspondence between the actual bone-only metastasis and the nomogram predictions implied poor calibration of the nomogram in the validation cohort, be it in the whole cohort or when stratified by breast cancer subtype.

CONCLUSION

This external validation study of the MDACC nomogram showed limitations in its generalizability to a new and independent European patient population.

The landscape of metastatic progression patterns across major human cancers

The majority of patients with solid malignancies die from metastatic burden. However, our current understanding of the mechanisms and resulting patterns of dissemination is limited. Here, we analyzed patterns of metastatic progression across 16 major cancer types in a cohort of 1008 patients with metastatic cancer autopsied between 2000 and 2013 to assess cancer specific progression patterns of disease and related risk predictions. The frequency and location of metastases were evaluated in and across 1) 16 major cancers, 2) smoking- and non-smoking-related cancers and 3) adeno- and squamous cell carcinoma. Associations between primary and secondary sites were analyzed by the fractional and the relative risk methods. We detected significantly different cancer specific patterns of metastatic progression with specific relative risk profiles for secondary site involvement. Histology and smoking etiology influenced these patterns. Backward analysis showed that metastatic patterns help to predict unknown primary sites. Solid malignancies maintain a unique and recurrent organ tropism to specific secondary sites which does not appear to be strongly influenced by advances in cancer medicine as shown by comparison with previous data sets. The delineated landscape of metastatic progression patterns is a comprehensive data resource to both clinical and basic scientists which aids fostering new hypotheses for cancer research and cancer therapies.

Metastasis of circulating tumor cells: favorable soil or suitable biomechanics, or both?

Metastasis is the end product of a multistep process where cancer cells disseminate and home themselves in distant organs. Tumor cell extravasation is a rare, inefficient and transient event in nature and makes its studies very difficult. Noteworthy, little is known about how cancer cells arrest, adhere and pass through the endothelium of capillaries. Moreover, the key events driving metastatic growth in specific organs are not well understood. Thus, although metastasis is the leading cause of cancer-related death, how cancer cells acquire their abilities to colonize distant organs and why they do so in specific locations remain central questions in the understanding of this deadly disease. In this review, we would like to confront 2 concepts explaining the efficiency and location of metastatic secondary tumors. While the "seed and soil" hypothesis states that metastasis occurs at sites where the local microenvironment is favorable, the "mechanical" concept argues that metastatic seeding occurs at sites of optimal flow patterns. In addition, recent evidence suggests that the primary event driving tumor cell arrest before extravasation is mostly controlled by blood circulation patterns as well as mechanical cues during the process of extravasation. In conclusion, the organ tropism displayed by cancer cells during metastatic colonization is a multi-step process, which is regulated by the delivery and survival of circulating tumor cells (CTCs) through blood circulation, the ability of these CTCs to adhere and cross the physical barrier imposed by the endothelium and finally by the suitability of the soil to favor growth of secondary tumors.

Dietary soy isoflavones increase metastasis to lungs in an experimental model of breast cancer with bone micro-tumors

Bone is one of the most common sites for metastasis in breast cancer (BC). Micro-metastasis in bone marrow was detected in 30% of patients with stage I, II, or III BC at primary surgery and is a strong indicator of poor prognosis. The role dietary soy isoflavones play in BC with bone micro-metastasis is unclear. In this study, we examined the effects of genistein, daidzein, (-)-equol or a mixture of soy isoflavones on BC with bone micro-metastasis using an experimental model of murine mammary cancer 4T1 cells engineered with luciferase. A small number (1000) of 4T1 cells were injected into the tibia of female Balb/c mice to establish micro-tumors in bone. Soy isoflavones were supplemented in the AIN-93G diet at 750 mg/kg and were provided to mice from 3 weeks before to 3 weeks after cell injection. Bioluminescent imaging was conducted on day 2 (D2), D6, D8, D16 and D20 post cell injection and the results indicated dietary soy isoflavones enhanced the growth of bone micro-tumors on D8. Furthermore, dietary soy isoflavones stimulated metastatic tumor formation in lungs and increased Ki-67 protein expression in these metastasized tumors. In vitro, soy isoflavones (<10 µM) had limited effects on the growth, motility or invasion of 4T1 cells. Thus, the in vivo stimulatory effect could be likely due to systemic effects between the host, 4T1 tumors and soy isoflavones. In conclusion, soy isoflavones stimulate BC with bone micro-metastasis in mice and further investigations are needed regarding their consumption by BC survivors.

Estradiol increases ER-negative breast cancer metastasis in an experimental model

Breast cancer (BC) is the most common cancer affecting women in the United States and metastatic breast cancer is the leading cause of death. The role estradiol plays in ER-positive BC is well-documented, but the way it contributes to ER-negative BC remains unclear. In the present study, we utilized an experimental model of BC metastasis into lung by injecting ER-negative murine 4T1 cells into mice via the lateral tail vein. A 56 % metastasis occurrence rate following the injection of 5 × 10(3) cells was observed, thus this cell number was selected to study the potential stimulatory effect of estradiol on ER-negative BC metastasis. Female ovariectomized mice were randomized into estradiol and control groups with 16 mice per group, and estradiol pellets were implanted subcutaneously in the estradiol group. Results demonstrated that estradiol accelerated BC metastasis as indicated by bioluminescent imaging. In addition, estradiol enhanced metastatic tumor colony formation and increased the size of tumor nodules in the lungs, which were due, in part, to the increase in proliferative cells in the metastatic tumors. In vitro, estradiol increased the motility and invasion of 4T1 cells, and the stimulatory effect on cell motility was not blocked by ICI 182, 780, confirming that ER was not involved in the process. Results from the present study suggest that estradiol plays a role in ER-negative BC metastasis in whole animals.

Implications of bone-only metastases in breast cancer: favorable preference with excellent outcomes of hormone receptor positive breast cancer

Purpose

The aim of the current study was to determine the incidence, clinical presentation, and treatment outcomes of "bone-only metastases" in patients with breast cancer and to analyze the impact of hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status on prognosis.

Materials and Methods

Between 1994 and 2007, of 968 patients with metastatic breast cancer who underwent palliative management at Samsung Medical Center, 565 (57%) relapsed with distant metastases. Of the 968, 146 (15%) had bone-only metastases during a median follow-up period of 75 months. Among the 146 patients with bone-only metastases, 122 (84%) were relapsed patients after curative surgery and 24 (26%) were initially metastatic cases.

Results

The median time from primary surgery to bone-only metastases of the 122 patients was 37 months (95% confidence interval [CI], 27 to 46 months). Bone-only metastases were more common in the HR-positive group than in the other subtypes (85% for HR+; 8.2% for HER2+; 6.8% for triple negative. Among all 146 patients, 75 (51%) were treated with hormone therapy. The median post-relapse progression-free survival was 15 months (95%CI, 13 to 17 months). The median overall survival was much longer in the HR+ patients than the HER2+ and triple negative breast cancer patients with marginal statistical significance (65 vs. 40 vs. 40 months, p=0.077).

Conclusion

Breast cancer patients with "bone-only metastases" had excellent clinical outcomes. Further study is now warranted to reveal the underlying biology that regulates the behavior of this indolent tumor, as it should identify 'favorable tumor characteristics' in addition to 'favorable preferential metastatic site.'

Metastasis: from dissemination to organ-specific colonization

Metastasis to distant organs is an ominous feature of most malignant tumours but the natural history of this process varies in different cancers. The cellular origin, intrinsic properties of the tumour, tissue affinities and circulation patterns determine not only the sites of tumour spread, but also the temporal course and severity of metastasis to vital organs. Striking disparities in the natural progression of different cancers raise important questions about the evolution of metastatic traits, the genetic determinants of these properties and the mechanisms that lead to the selection of metastatic cells.

Brain metastases: old problem, new strategies

Brain metastases from breast cancer are a common complication of the disease and alter the management of patients more than any other site of distant progression. Certain subgroups of patients are at high risk for developing CNS disease, warranting targeted research and perhaps screening for occult disease. Data from studies that include other solid tumor histologies provide the bulk of supporting evidence for the use of therapies, such as steroids, antiepileptic drugs, surgery, and radiation. However, there are several issues specific to brain metastases from breast cancer illustrating that this disease should be considered pathophysiologically distinct, and future research should be tailored accordingly.

Dietary Genistein Reduces Metastasis in a Postsurgical Orthotopic Breast Cancer Model

Metastatic spread, not primary tumor burden, is the leading cause of breast cancer deaths. For patient prognosis to improve, new systemic adjuvant therapies that are capable of effectively inhibiting the outgrowth of seeded tumor cells after surgical treatment of the primary breast tumor are needed. To facilitate the preclinical development of such therapies, relevant animal models of breast cancer metastasis that can mimic the postsurgical adjuvant setting are required. Here we developed a preclinical xenograft model of breast cancer metastasis where the primary tumor was removed by surgical resection before systemic adjuvant treatment. We used this model to assess the antimetastatic effect of postsurgical dietary intervention with the soy isoflavone genistein. The anticancer activity of genistein has been established in vitro and in vivo, however, few studies have tested the potential of genistein as an antimetastatic therapy. Using our model, we tested the efficacy of adjuvant treatment with genistein to inhibit the outgrowth of metastases postsurgery. To establish primary tumors, human breast carcinoma cells, MDA-MB-435/HAL, were implanted into the mammary fat pad of female nude mice. Primary tumors were left to grow for 5 weeks before being surgically removed. Mice were then randomized into two diet groups: control soy-free diet versus genistein-supplemented diet. Five weeks later, metastatic burden was assessed. Genistein reduced the percent metastatic burden in the lungs by 10-fold. These results indicate that dietary intervention following cancer surgery can affect the outgrowth of seeded tumor cells. The availability of well-characterized, clinically relevant animal models for studying factors that regulate metastatic outgrowth postsurgery will provide an important tool for developing new systemic adjuvant therapies.

Reovirus as an experimental therapeutic for brain and leptomeningeal metastases from breast cancer

Brain and leptomeningeal metastases are common in breast cancer patients and our current treatments are ineffective. Reovirus type 3 is a replication competent, naturally occurring virus that usurps the activated Ras-signaling pathway (or an element thereof) of tumor cells and lyses them but leaves normal cells relatively unaffected. In this study we evaluated reovirus as an experimental therapeutic in models of central nervous system (CNS) metastasis from breast cancer. We found all breast cancer cell lines tested were susceptible to reovirus, with > 50% of these cells lysed within 72 h of infection. In vivo neurotoxicity studies showed only mild local inflammation at the injection site and mild communicating hydrocephalus with neither diffuse encephalitis nor behavioral abnormalities at the therapeutically effective dose of reovirus (intracranial) (ie 10(7) plaque-forming units) or one dose level higher. In vivo, a single intratumoral administration of reovirus significantly reduced the size of tumors established from two human breast cancer cell lines and significantly prolonged survival. Intrathecal administration of reovirus also remarkably prolonged survival in an immunocompetent racine model of leptomeningeal metastases. These data suggest that the evaluation of reovirus as an experimental therapeutic for CNS metastases from breast cancer is warranted.

Does Hypervascularity of Liver Metastases as Detected on MRI Predict Disease Progression in Breast Cancer Patients?

OBJECTIVE

The aim of our study was to evaluate the association of the vascularity of liver metastases, as characterized by MRI, and disease progression in breast cancer patients.

MATERIALS AND METHODS

Sixteen breast cancer patients with liver metastases who underwent MRI before and after systemic therapy were retrospectively identified. On the basis of comparison of each MRI examination with the previous examination, disease status of the patients was classified as complete response, partial response, stable disease, or progressive disease. Liver metastases were characterized as hyper- or hypovascular on the basis of the degree of enhancement in the arterial, portal, and interstitial phases of imaging after administration of a contrast agent. Fisher's exact test and ordinal logistic regression models, including the type of systemic therapy, presence of multiple metastases, and hormone receptor status, were used to estimate the unadjusted and risk-adjusted association between the presence of hypervascular liver metastases and disease progression.

RESULTS

All patients in our sample (n = 16) were women and most (12/16, 75%) were white. Their median age was 51.5 years. In unadjusted analyses, the association between the presence of hypervascular liver metastases and disease progression was statistically significant (p < 0.0001). In multiple logistic regression analyses, hypervascular liver metastases were found to be an independent predictor of disease progression. Patients with hypervascular liver lesions were 20.5 times more likely to experience disease progression than patients without hypervascular metastases (odds ratio, 20.5; 95% confidence interval, 5.1-83.5; p < 0.0001).

CONCLUSION

Our analysis provides suggestive evidence that disease progression can be predicted through MRI assessment of the vascularity of liver metastases in patients with breast cancer.

Analysis of gene expression involved in brain metastasis from breast cancer using cDNA microarray

BACKGROUND

Brain metastases occur in 15% to 30% of breast cancer patients, usually as a late event. The patterns of metastases to different organs are determined by the tumor cell phenotype and interactions between the tumor cells and the organ environment.

METHODS

We investigated the gene expression profile occurring in brain metastases from a breast cancer cell line. We used cDNA microarrays to compare patterns of gene expression between the mouse breast cancer cell line Jyg MC (A) and a subline that often metastasis to brain, (B).

RESULTS

By Microarray analysis about 350 of 21,000 genes were significantly up-regulated in Jyg MC (B). Many candidate genes that may be associated with the establishment of brain metastasis from breast cancer were included. Interestingly, we found that the expression of astrocyte derived cytokine receptors (IL-6 receptor, TGF-beta receptor and IGF receptor) were significantly increased in Jyg MC (B) cells. These results were confirmed by RT-PCR.

CONCLUSIONS

These results suggest that cytokines produced by glial cells in vivo may contribute, in a paracrine manner, to the development of brain metastases from breast cancer cells.

Prognostic significance of the number of bone scan abnormalities at the time of initial bone metastatic recurrence in breast carcinoma

BACKGROUND

To gain insight into the factors that contribute to the more favorable prognosis associated with recurrence limited to bone in patients with breast carcinoma, the authors analyzed the number of sites of initial involvement identified on radionuclide bone scans in relation to long term outcome.

METHODS

Records of 641 patients with clinical Stage I-III breast carcinoma that originally was diagnosed in 1974-1985 were reviewed. During follow-up, 295 patients (46%) experienced distant recurrence, including 116 with bone as the sole initial site of metastatic disease. Radionuclide bone scans identified the initial site(s) of recurrence in 113 of these latter 116 patients, and these studies were categorized by the number of skeletal lesions subsequently confirmed as metastases (1, 2, or > or = 3). Survival from time of recurrence and time of original diagnosis was analyzed using Kaplan-Meier methods, and factors associated with recurrence and mortality were examined using logistic and Cox regression.

RESULTS

Median survival from time of recurrence was 35 months in the patients with bone-only metastases, compared with 11-26 months for all other sites of visceral recurrence exclusive of bone. Number of positive lymph nodes and estrogen receptor status were the only predictive variables for recurrence. Median survival from time of recurrence and time of original diagnosis for the 3 bone scan categories was: 1 lesion (n = 47), 53 and 86 months; 2 lesions (n = 22), 38 and 68 months; and > or = 3 lesions (n = 44), 22 and 58 months (P < 0.0001 and P < 0.005 for 1 and 2 lesions vs. > or = 3). In the "bone-only" group, the number of scan lesions was the strongest predictor of length of survival.

CONCLUSIONS

Patients with breast carcinoma who experience a recurrence in bone at only one or two sites initially have a survival advantage over those with more extensive (> or = 3 sites) skeletal metastases and those with metastatic disease involving other visceral organs.

Identification of a novel aspartic-like protease differentially expressed in human breast cancer cell lines

Four different human breast cancer cell lines were examined to search for genes associated with tumor growth and metastasis. Each of these cell lines, MDA-MB-453, MCF-7, MDA-MB-231 and MDA-MB-435, displays different phenotypic characteristics ranging from poorly to highly tumorigenic and metastatic. The differences in gene expression profiles of these cell lines generated by differential display technique should allow one to identify candidates as putative oncogenes or tumor/metastasis suppressor genes. A novel cDNA expressed in the highly tumorigenic and metastatic cell line, MDA-MB-435, was identified and isolated by this approach. The function for this gene, designated ALP56 (aspartic-like protease 56 kDa), in tumor progression is suggested by the homology of the encoded protein to aspartic proteases, such as cathepsin D. The amino acid residues in two catalytic domains of this family are highly conserved in those domains of ALP56. Northern hybridization indicated that the expression of ALP56 is associated with growth and metastasis of MDA-MB-435 tumors in immunodeficient mice. In situ hybridization of biopsies from breast cancer and colon cancer patients indicated that ALP56 is upregulated in human primary tumors and liver metastasis. These results suggest that this novel gene correlates with human tumor progression.

Molecular detection of cancer cells in bone marrow and peripheral blood of patients with operable breast cancer. Comparison of CK19, MUC1 and CEA using RT-PCR

We have compared three different RT-PCR procedures to measure cytokeratin 19 (CK19), carcinoembryonic antigen (CEA) and mucin MUC1 gene expression in order to determine their diagnostic value in detecting tumour cells in bone marrow aspirates of patients with operable breast cancer. In an experimental model, the best sensitivity was observed for CK19 and MUC1 RT-PCR assays, although only the CEA and CK19 assays showed good specificity. The study of 42 patients showed that a 'CK19 positive/CEA positive' RT-PCR assay in bone marrow correlated positively with a positive axillary lymph node status (N(0) versus N(1-3), P<0.05). Both assays were also positive in 17% of node negative patients. RT-PCR assays were more sensitive in bone marrow than in peripheral blood. Our results suggest that CK19 and CEA RT-PCR assays are powerful methods for detecting disseminated breast cancer cells. A larger study with long-term follow-up is required in order to clarify their clinical usefulness.

Treatment and outcome of brain metastasis as first site of distant metastasis from breast cancer

Twenty-eight consecutive patients with breast cancer were analyzed who presented with a single brain metastasis as first site of distant metastasis. The response to surgery with postoperative radiation therapy (RT) (9 patients) and to non-surgical therapy as first-line treatment was 100% and 89% respectively with a significant difference in median recurrence-free intervals of 23 months and of 5 months respectively (p = 0.033). Retreatment of a local relapse by surgery (+/-RT, +/-chemotherapy) or by non-surgical treatment resulted in a response in 6 of the 7 operated patients and in 5 of the 6 non-operated patients with a median duration of response of 7 months (range 2-20 months) and of 3 months (range 2-4 months) respectively. The overall median survival of the 28 patients with a single brain metastasis was 16 months (range 2-39 months). The median survival in the primarily operated patients was 23 months, in the primarily not-operated group 10 months, and in the never-operated group 9 months. In comparison, the response to non-surgical treatment in 20 consecutive patients who presented with multiple brain metastases as first site of distant metastasis was 55% with a median recurrence free interval of 4 months. The median survival in this group was 4 months, which was significantly shorter than survival of patients with single brain metastasis (p = 0.0036). These results suggest that breast cancer patients with a single brain metastasis as first presentation of relapse constitute a specific subgroup with a favorable response to treatment and a long survival especially if they can be treated by surgery with postoperative RT.

Role of surgery in the treatment of brain metastases in patients with breast cancer

BACKGROUND

Patients whose brain metastases from breast cancer are treated nonsurgically have a median length of survival ranging from 2.5 to 7.5 months, and a median time to recurrence ranging from 2 to 5 months. Patients treated with radiotherapy have a median length of survival ranging from 3 to 4 months. Those treated with chemotherapy have a median length of survival ranging from 5.5 to 7.5 months.

METHODS

We conducted a retrospective analysis on 63 patients treated over a 10-year period. Only patients who underwent surgery for nonrecurrent brain metastases were studied. Sixty-one patients (97%) underwent surgery within 2 weeks of diagnosis of the brain metastases.

RESULTS

The median length of survival was 16 months (95% confidence interval [CI] 11 to 22 months), and the 5-year survival rate was 17% (CI 9% to 29%). Brain metastases recurred in 27 patients at a median interval of 15 months (CI 12 to 24 months). Eleven patients had local recurrence, 10 had distal recurrence, and seven developed leptomeningeal disease. Significant prognosticators of length of survival were age (p = 0.011), menopause status (p = 0.10), postoperative radiotherapy (p = 0.054), preoperative neurologic status (p = 0.011), and preoperative systemic disease status (p = 0.0003). Systemic disease status had a significant effect on the length of survival but not on the time to recurrence.

Brain metastasis model in athymic nude mice using a novel MUC1-secreting human breast-cancer cell line, MA11

The MA11 human breast-cancer cell line was established with cells isolated from a bone-marrow sample using immunomagnetic beads conjugated to the anti-MUC1 antibody BM-2. The cell line showed a selective preference for metastasising to the brain in athymic nude mice. Following injection of MA11 cells into the left ventricle of the heart, brain metastases developed in 87% (20/23) animals, with a mean latency until development of neurological symptoms of 65 days. Necropsy and histological examination revealed tumour nodules of varying sizes throughout the brain, invading both grey and white matter of both hemispheres, and with extensive involvement of the cerebellum. MRI spin-echo images indicated brain lesions in some animals that were subsequently confirmed by histology. Three mice showed small tumour nodules (1-2 mm) in the lung, and 2 had solitary lesions (< 1 mm) within the spinal cord. Metastases were not detected in bone, liver, adrenal gland, kidney, spleen or heart. The human MUC1 mucin, as determined by a europium-based immunoradiometric assay, was detected in the serum of 9/11 animals that showed histological evidence of brain metastases. The mucin could not be found in mouse serum samples taken before day 46. The concentration range of MUC1 observed was from <1 to >50 U/ml, and did not appear to correlate with the size or number of tumours as determined from histological sections. This new model provides an opportunity to study the mechanisms of clinically relevant organ-selective metastases and may be of use in evaluating novel treatment for brain metastases in breast cancer.

Does supportive pamidronate treatment prevent or delay the first manifestation of bone metastases in breast cancer patients?

The effect of pamidronate treatment on the first development of bone metastases was investigated in 124 patients with breast cancer, with either locally advanced disease (n = 33) or extraskeletal metastases (n = 91), but no bone metastases in a randomised, multicentre, open controlled study. Patients were assigned to treatment with oral pamidronate, 300 mg/day, (n = 65) or to a control group (n = 59). Tumour therapy was freely allowed. A first clinical event of skeletal morbidity occurred in 22% pamidronate and 20% control patients; unequivocal first radiological manifestation of bone metastases was found in 36% pamidronate and 27% control patients (n.s.). The actuarial risk of a first skeletal event was similar in both groups. Quality-of-life measurements of bone metastases-related aspects showed no differences between the two groups. 19 patients withdrew from the study because of gastrointestinal complaints attributed to pamidronate. We conclude that supportive oral pamidronate treatment (300 mg/day) does not prevent nor delay the development of bone metastases in breast cancer patients at risk.

Brain metastases in breast cancer; natural history, prognostic factors and outcome

One hundred and thirty seven breast cancer patients with CT scan documented brain metastasis (BM) were reviewed. Occurrence of brain as first site of relapse was associated with adjuvant systemic therapy of the primary tumor. Multivariate analysis showed significantly longer survival in patients without manifest systemic disease, in patients with a solitary BM, in those with neurologic symptoms present for more than 4 weeks prior to diagnosis, and in those treated with chemotherapy after diagnosis. When controlling for prognostic factors no significant difference in survival was found between surgery and radiotherapy (RT) as treatment of a solitary lesion. Tumor size, tumor necrosis and mass effect had no demonstrable influence on survival. Overall median survival was 16 weeks and 19% survived one year. Neurologic disease was the cause of death or a major contributing factor to it in 68% of the patients, indicating the need for improvement of the treatment of BM itself. These results warrant further studies on the value of surgery, RT and chemotherapy in solitary as well as multiple BM from breast carcinoma.

Thermoradiotherapy for residual microscopic cancer: elective or post-excisional hyperthermia and radiation therapy in the management of local-regional recurrent breast cancer

A Phase I/II study was undertaken to investigate the efficacy and side effects of combined hyperthermia and radiation therapy in the management of presumed or known microscopic residual tumors. Between February 1985 and March 1991, 262 fields in 89 patients with local-regional recurrent breast cancer were treated with externally administered hyperthermia and radiation therapy. Thirty-eight fields were treated for microscopic residual disease following excisional biopsy of nodular recurrences and 224 fields were treated electively for areas at high risk for local recurrences adjacent to fields with macroscopic residual disease. Mechanically mapped temperatures were monitored throughout the field in all treatments. All patients had at least one follow-up evaluation at three weeks or more following completion of treatment. The majority of the fields were in patients who had had extensive prior therapy including radiation therapy (54%), chemotherapy (71%), and hormonal therapy (51%). All fields received hyperthermia (1-6 treatments: average 1.74) and radiation therapy (average dose: 42.4 Gy); concurrent hormonal therapy was administered in 37% of the treatments and no fields received concurrent chemotherapy. The treatments were well tolerated, no life-threatening complications were noted. Averages for all fields of the minimum, maximum, and average measured interstitial temperatures were 40.2 degrees C, 45.3 degrees C, and 42.8 degrees C, respectively. The three-year actuarial local-control rate for all 262 treated fields was 68%. Parameters characterizing the initial breast cancer, the patient and tumor at the time of hyperthermia, and the treatment were studied in univariate and multivariate analysis for correlation with duration of local control within the hyperthermia treatment field. Parameters in the best five covariate model correlating with the duration of local control included: estrogen receptor status of the initial breast cancer; initial T-stage; time from initial breast cancer to first failure; age at hyperthermia; and concurrent radiation dose (p-value for model less than 0.000001). Six covariate models adding anatomic site of disease, field type, mean minimum temperatures, and mean percent temperatures greater than or equal to 40 degrees C all resulted in improved models. Randomized controlled studies stratifying for these pretreatment parameters are felt warranted to confirm the value of adjuvant hyperthermia in the elective treatment of areas of high risk for local-regional recurrent breast cancer and in fields following surgical excision of recurrent disease, particularly in patients in whom full dose radiation therapy cannot be safely administered.

Metastatic pattern of infiltrating lobular carcinoma of the breast: an autopsy study

We analyzed the autopsy records and autopsy histological slides of 261 patients with breast carcinoma who died at the Institute of Oncology, Ljubljana, from January 1972 to October 1989, with particular attention to the metastatic pattern of infiltrating lobular carcinoma (ILC) which we compared with infiltrating ductal carcinoma (IDC). In 226 of 261 patients who died with metastatic disease there were 25 cases of ILC, 195 cases of IDC, 4 cases of mixed IDC-ILC, and 2 cases of mucinous carcinoma. There was no statistically significant difference in frequency of metastases to common metastatic sites, such as the liver, bone, and pleura, with the exception of the lungs, in which IDC metastases prevailed (P less than 0.006). By contrast, a statistically highly significant prevalence of ILC metastases to the peritoneum/retroperitoneum, hollow viscera, internal genital organs, leptomeninges, and myocardium was found (P values of less than 0.006- less than 10(-6). The metastases to these sites were characterized by diffuse growth of neoplastic cells that infiltrated in a lymphoma or leukemia-like fashion. Such metastases may remain clinically silent for a long time, in spite of their extensiveness. The difference of metastatic pattern between ILC and IDC is insufficiently appreciated in most of the published studies on ILC.

Distribution of metastases in breast carcinoma: CT evaluation of the abdomen

To determine the frequency and distribution of extrahepatic and extraskeletal metastases in patients with breast carcinoma, the abdominal CT scans of 260 consecutive patients were systematically evaluated. Extrahepatic and extraskeletal metastases were demonstrated in 26 patients (10%). Confirmation of findings was made by biopsy, autopsy, or by demonstration of progression or regression of disease. Twelve patients (4.6%) demonstrated metastases to the stomach, eleven of whom presented with a linitis plastica pattern. Retroperitoneal and/or mesenteric adenopathy was noted in 10 patients (3.8%), of whom three demonstrated associated hydronephrosis and one demonstrated associated biliary obstruction. Ascites was seen in 14 (5.4%) and peritoneal carcinomatosis in 7 (2.6%). Genitourinary involvement included metastases to the kidney (one case), ureter (one), and uterus (one). Direct invasion of the diaphragm by adjacent pleural metastases (two cases) as well as a soft tissue metastasis (one case) was also demonstrated. Metastases to the ovaries, adrenals, or pancreas could not be identified. Although lesions to the liver and skeleton account for the largest group of metastases from breast carcinoma seen in the abdomen, one should be aware of the potential for other locations of metastatic disease.

Value of gross cystic disease fluid protein-15 in distinguishing metastatic breast carcinomas among poorly differentiated neoplasms involving the ovary

Women with breast cancer have an increased risk of developing primary ovarian tumors. Because a differential diagnosis between primary and metastatic tumors may be difficult in poorly differentiated ovarian neoplasms, breast carcinoma markers may be helpful in establishing the primary site of origin. Gross cystic disease fluid protein-15 (GCDFP-15), a well-known marker of apocrine differentiation, has been reported as a highly specific and sensitive breast carcinoma marker. To evaluate the usefulness of GCDFP-15 as a marker for metastatic breast cancer, we have studied, by the avidin-biotin-peroxidase technique, 14 cases of breast cancer metastatic to the ovary and compared them with 32 primary ovarian tumors and seven cases of ovarian metastases other than breast in origin. Two cases of primary ovarian cancer metastatic to the breast were also included. A strong cytoplasmic immunostaining was found in 10 of 14 cases (71%) of ovarian metastasis from breast carcinoma, and in most cases a characteristic paranuclear staining was noted. All primary ovarian tumors were negative. Ovarian metastases from tumors other than breast and both cases of ovarian carcinoma metastatic to the breast were negative. These results are highly significant (P less than .00001) and demonstrate the value of GCDFP-15 in establishing a primary breast origin among neoplasms of unknown origin involving the ovaries.

The biology of metastatic breast cancer

Early detection and surgical removal of breast cancer are most effective in managing a disease that may affect up to one in ten women in North America and Western Europe. However, one of the most important prognostic indicators for breast cancer is the presence of neoplastic cells in the axillary lymph nodes. The dissemination of cells from a primary lesion, resulting in the progressive growth of metastatic carcinoma in distant sites (including bone, lungs, liver, and brain) is the most common cause of death in breast cancer patients. Experimental studies on the biology of metastatic breast cancer have used rodent tumor systems, and, in recent years, the transplantation of human breast carcinoma cells into athymic mice. The results of such studies, combined with clinical observations, suggest that metastasis is not a random event. The formation of secondary lesions is the result of a sequence of selective events. A better understanding of the metastatic phenotype from cellular and molecular analyses will provide a basis for rational approaches to preventing and treating this most lethal aspect of breast cancer.

Stem cells and the development of mammary cancers in experimental rats and in humans

Evidence based on immunocytochemical staining and ultrastructure suggests that morphological gradations between epithelial and myoepithelial cells, and possibly between epithelial cells and alveolar-like cells occur in terminal ductal structures of rat and human mammary glands. The benign carcinogen-induced rat and benign human mammary tumors can contain epithelial, myoepithelial-like and alveolar-like cells, whereas the malignant counterparts mainly contain only epithelial-like cells. Clonal epithelial cell lines from normal rat mammary glands, benign tumors, and SV40-transformed human mammary glands can differentiate to either myoepithelial-like or alveolar-like cells. In those of the rat, the differentiation processes occur in steps: intermediate cells along the myoepithelial-like pathway resemble intermediates in terminal ductal structures in vivo, and can also generate certain well-differentiated mesenchymal elements of the original tumours. Differentiation of the benign rat cells to alveolar-like cells with mammatrophic hormones and retinoids in vitro leads to a reduction in their tumor-forming ability in vivo. Cell lines from malignant rat mammary tumors of increasing metastatic potential and from human ductal carcinomas largely fail to yield myoepithelial-like or alveolar-like cells and are relatively slow-growing. Growth of the rat mammary epithelial cells in culture is stimulated by a pituitary-derived mammatrophic growth factor (PMGF), prostaglandin E2, and alpha-transforming growth factor; the response of the malignant cell lines to PMGF is reduced. It is suggested that stem cells exist in the rat and human glands that are capable of differentiating to the other major cell types of the mammary parenchyma, and that during the carcinogenic process they generate genetically unstable cells which lose their ability to differentiate and attempt to maximise their intrinsically slow growth rate.

The clinical course of bone metastases from breast cancer

All patients with carcinoma of the breast seen in this Unit since 1970 were reviewed to study the incidence, prognosis, morbidity and response to treatment of bone metastases. The biological characteristics of the primary tumour were compared in patients relapsing first in bone or liver. Sixty-nine percent of patients dying with breast cancer had bone metastases and bone was the commonest site of first distant relapse. Bone relapse was more common in receptor positive or well differentiated (grade 1) tumours. The median survival was 24 months in those with disease apparently confined to the skeleton compared with 3 months after first relapse in liver. Ten percent of patients with breast cancer developed hypercalcaemia. All had metastatic disease and 85% had widespread skeletal involvement. Fifteen percent of patients with disease confined to the skeleton developed hypercalcaemia. The response in bone to primary endocrine therapy, and chemotherapy, was apparently less than the overall response achieved. A large proportion had apparently static disease reflecting the insensitivity of the UICC assessment criteria. The duration of survival in these patients was similar to responding patients, suggesting a tumour response may occur in the absence of discernable radiological evidence of healing.

Pathogenesis and characteristics of spontaneously metastasizing mammary carcinomas and the general principle of metastasis

Chemical mammary carcinogenesis in immunologically attennuated W/Fu female rats, subjected to specific and nonspecific immunostimulations, yielded many spontaneously metastasizing adenocarcinomas with varying degrees of glandular differentiation, and growth rates. The pathogenesis of these tumors suggested that while carcinogens transform target cells, the host immune system endows them with metastatic potential. The metastatic pathways were recognizable as hematogenous, lymphogenous, or hematogenous-lymphogenous combined, according to the capacity of the tumor cells to intravasate the lymphatic and/or vascular channel and traverse the pulmonary artery. The same metastatic pattern can be reproduced with cells from any of the organs involved, indicating that it is inherent in all cells within a given tumor, rather than being determined by the organs they colonize. The biological, biochemical and immunological characteristics of these tumors resemble human breast cancer thus becoming an effective tool in the formulation of the general principle of metastasis by malignant solid tumors.

17 beta-estradiol regulates and v-Ha-ras transfection constitutively enhances MCF7 breast cancer cell interactions with basement membrane

The interaction of a line of human breast carcinoma cells (MCF7) with basement membrane components, particularly laminin, was altered by exposure of the cells to estrogen as well as by transfection of the cells with the v-Ha-ras oncogene. In both cases, the cells show a greater ability to attach to a laminin substrate, to migrate to laminin, to grow in the presence of a basement membrane matrix, and to cross barriers of reconstituted basement membrane. These responses were associated with an increase in the expression of laminin receptors. It is postulated that the increase in the invasive behavior of the cells treated with estrogen or transfected with v-Ha-ras is related to the increased number of laminin receptors and their interaction with laminin. Estrogen had no discernible effect on the v-Ha-ras transfected cells. It appears that in the MCF7 cells, the malignant phenotype is under hormonal control and that this control is bypassed after v-Ha-ras transfection.