The tumor macroenvironment and systemic regulation of breast cancer progression

Breast cancer is the most common malignancy among women worldwide and is the most common cause of death for women between 35 and 50 years of age. Women with breast cancer are at risk of developing metastases for their entire lifetime and, despite local and systemic therapies, approximately 30% of breast cancer patients will relapse (Jemal et al., 2010). Nearly all breast cancer related deaths are due to metastatic disease, even though metastasis is considered to be an inefficient process. In some cases, tumor cells disseminate from primary sites at an early stage, but remain indolent for protracted periods of time before becoming overt, life-threatening tumors. Little is known about the mechanisms that cause these indolent tumors to grow into malignant disease. Because of this gap in our understanding, we are unable to predict which breast cancer patients are likely to experience disease relapse or develop metastases years after treatment of their primary tumor. A better understanding of the mechanisms and signals involved in the exit of tumor cells from dormancy would not only allow for more accurate selection of patients that would benefit from systemic therapy, but could also lead to the development of more targeted therapies to inhibit the signals that promote disease progression. In this review, we address the systemic, or "macroenvironmental", contribution to tumor initiation and progression and what is known about how a pro-tumorigenic systemic environment is established.     

Concomitant expression of the chemokines RANTES and MCP-1 in human breast cancer: a basis for tumor-promoting interactions

The chemokines RANTES (CCL5) and MCP-1 (CCL2) were suggested to contribute, independently, to breast malignancy. In the present study, we asked if the two chemokines are jointly expressed in clinical samples of breast cancer patients, and do they interact in breast tumor cells. We found that RANTES and MCP-1 were expressed by breast tumor cells in primary tumors of Ductal Carcinoma In Situ and of Invasive Ductal Carcinoma, but minimally in normal breast epithelial duct cells. The chemokines were also detected in metastases and pleural effusions. Novel findings showed that co-expression of RANTES and MCP-1 in the same tumor was associated with more advanced stages of disease, suggesting that breast tumors "benefit" from interactions between the two chemokines. Accordingly, MCP-1 significantly promoted the release of RANTES from endogenous pre-made vesicles, in an active process that depended on calcium from intracellular and extracellular sources, and on intracellular transport of RANTES towards exocytosis. Our findings show a chemokine-triggered release of stored pro-malignancy chemokine from breast tumor cells. These observations support a major tumor-promoting role for co-expression of the chemokines in breast malignancy, and agree with the significant association of joint RANTES and MCP-1 expression with advanced stages of breast cancer.     

The biology of breast cancer at the cellular level

Two properties seem fundamental to cancer; heterogeneity and progression (Foulds (1975) Academic Press, New York; Heppner et al. (1979) Commentaries on Research in Breast Disease, Vol. 1 (Bulbrook, R. and Taylor, D.J., eds.), pp. 177-191, Plenum Press, New York). Relatively little is understood about the premalignant stages of human breast disease in vivo. When the disease manifests as invasive carcinoma, its behavior exhibits great diversity, sometimes metastasizing rapidly, while in other cases 10-30 years pass before metastases proliferate. Here we review various aspects of breast cancer in vivo and consider how they predict properties of breast cancer found in culture. All of the experiments are consistent with the hypothesis proposed by Nowell (1976) Science 194, 23-28, that a fundamental aspect of malignancy is an increased genetic instability and that many of the cells within tumors are nonviable results of genetic instability. We suggest that most of the viable cells within primary breast carcinomas are diploid and are not yet capable of aspects of metastatic spread. What these cells have attained is an increased propensity for genetic instability which enables them to generate randomly aneuploid but frequently lethal genetic configurations. Occasionally one of these altered genomes is associated with the ability to proliferate at a metastatic site. This hypothesis implies that metastases from various patients may have arisen by divergent pathways and may also be divergent in many other aspects of their physiology, unrelated to malignancy. Such extreme heterogeneity may hamper attempts to understand fundamental aspects of malignancy. Hence we suggest that the less anaplastic and less divergent diploid cells within the primary carcinomas might be an important resource to gain insights into the critical alterations that are responsible for initiating frankly malignant behavior.     

Behavior of metastatic and nonmetastatic breast tumors in old mice

Breast cancer incidence and mortality increase with age. A better understanding of the biological behavior of metastatic and nonmetastatic breast tumors in older subjects may help to develop improved breast cancer therapies. In this study, we used syngeneic metastatic (4TO7cg) and nonmetastatic (64pT) mouse breast tumor models at three age levels to evaluate various characteristics that are considered to be important for effective anti-breast cancer immunotherapy. These included tumor size and growth, metastases, vascularization, gene expression levels of the tumor-associated antigen (TAA) Mage-b (homologous to human MAGE-B) in primary breast tumors and metastases, and the presence of CD4(+) and CD8(+) T cells in the inguinal lymph nodes at the site of the tumor. The primary breast tumors and metastases were generated by injection of mouse mammary tumor cell lines 4TO7cg or 64pT into a mammary fat pad of normal 3-, 9-, or 21/24-month old BALB/c mice. In the nonmetastatic breast tumor model, significantly smaller tumors were observed in old compared with young mice. This was associated with a significant increase in the percentage of CD8(+) T cells in inguinal lymph nodes and significantly higher Mage-b expression levels in the primary tumors at old age. In the metastatic (4TO7cg) breast tumor model, a less pronounced, not statistically significant, smaller tumor size was found in the old mice, without a difference in the percentage of CD8(+) T cells or Mage-b expression levels. However, in this mouse model almost all metastases showed high levels of Mage-b expression (2- to 3-fold higher than the primary tumors in the same animals) regardless of age. These results indicate that the metastatic and nonmetastatic breast tumor models could be useful model systems to analyze how breast cancer vaccines for humans can be tailored to old age.     

Simultaneous bilateral breast carcinoma: Histopathological characteristics and CD44/catenin-cadherin profile

AIMS: Family history of breast carcinoma, multicentric tumor foci in one breast, and in situ lobular carcinoma increase the risk of bilateral breast cancer (BBC), synchronous or metachronous. Synchronous tumors are designated as simultaneous breast carcinoma if they appear at the same time. The CD44 family and cadherin/catenin immunophenotype of this group of BBCs has not yet been evaluated. The aim of this study was to compare clinicopathological characteristics and immunohistochemical profiles of simultaneous BBC and corresponding lymph node metastases in eight patients. METHODS AND RESULTS: In toto 15 primary and 9 metastatic tumors were evaluated. The expression of CD44 variant isoforms, beta-catenin, E, P and N-cadherin were evaluated by immunohistochemistry. Rare types of breast carcinoma were frequent in this group of patients. There were 6 pleomorphic lobular, 5 invasive ductal of usual type, 3 atypical medullary carcinomas, 2 mucinous and one invasive micropapillary carcinoma. The expression CD44v6 was most frequent, followed by CD44v3-10, CD44v5, and CD44v3. CD44v4 was generally not expressed. E-cadherin was expressed in 80% primary tumors, 40% expressed N-cadherin, and 66% expressed P-cadherin. CONCLUSIONS: Generally, simultaneous carcinomas had different morphology and different immunophenotype. Each primary tumor was more similar to its corresponding metastatic tumor than to the contralateral primary tumor.     

Bone metastases: prognostic applications of cytometric DNA analysis

OBJECTIVE: To examine DNA parameters as prognostic factors for developing metastases. STUDY DESIGN: Image cytometry was used to determine DNA content of 21 tumors and 28 metastases. DNA ploidy status, 2c deviation index (2cDI) and DNA malignancy grade (DNA-MG) (based on the variation of nuclear DNA content of tumor cells around the normal DNA [2c] peak) were examined for their prognostic value. RESULTS: Twenty of 21 tumors showed aneuploid content, and 1 tumor showed diploid DNA content. Twenty-one bone metastases showed aneuploid cells. In 6 cases both euploid and aneuploid cells were detected. In 1 metastasis only euploid cells were present. DNA-MG was increased in bone metastases (mean, 2.4) as compared to the corresponding primary tumor (mean, 2.2) in most of the cases. The mean value of the 2cDI was 30.07 in primary tumors and 42.5 in metastases. Twelve bone metastases had a higher 5cEE than did the primary tumor. CONCLUSION: Diploid and aneuploid cells were able to leave a tumor and establish metastases. DNA-MG and 2cDI were increased in metastases in comparison with the primary tumor, but even tumors with lower DNA-MG had metastatic potential.     

Pancreatic solitary and synchronous metastasis from breast cancer: a case report and systematic review of controversies in diagnosis and treatment

Background

Metastases from breast cancer cause the frequent involvement of lung, bone, liver, and brain, while the occurrence of metastases to the gastrointestinal tract is rare, and more frequently discovered after a primary diagnosis of breast cancer. Solitary pancreatic metastases from breast cancer, without widespread disease, are actually unusual, and only 19 cases have been previously described; truly exceptional is a solitary pancreatic metastasis becoming evident together with the primary breast cancer.

Case presentation

A 68-year-old woman reported general fatigue, lethargy, and jaundice. Abdominal ultrasound (US) and magnetic resonance imaging (MRI) showed an ampulloma of Vater’s papilla; moreover, a neoplastic nodule in the left breast was diagnosed. She underwent surgery for both breast cancer and ampulloma of Vater’s papilla. Pathological examination of pancreatic specimen, however, did not confirm primary carcinoma of the duodenal papilla, but showed a metastatic involvement of pancreas from lobular breast cancer. Immunohistochemistry has been essential to confirm the origin of the malignancy: hormone receptors and mammaglobin were expressed in both the primary breast tumor and the pancreatic metastasis.

Conclusions

This is one of the few reported cases in literature of an isolated and synchronous pancreatic metastasis from breast cancer, where the definitive diagnosis was obtained only after surgery. We discuss the controversies in this diagnosis and the choice of correct treatment. The surgical resection of solitary metastases can be performed in the absence of disseminated disease.     

Analysis of DNA and morphometry in breast carcinoma

Feulgen-stained imprints and smears from 730 cases of invasive breast cancer were investigated using an image analysis system. From each tumor sample 100 cells were randomly scanned and several DNA and morphometrical parameters evaluated. Their prognostic value for a prediction of distant metastases within 5 years was investigated with the multivariate Cox regression analysis, which was performed for all consecutive cases, as well as for node-negative and node-positive patients separately. The multivariate analyses showed a strong prognostic value of the anisonucleosis (variation of nuclear radius) and the DNA histogram type in addition to the nodal status, the tumor size (pT), and the histological tumor grade. However, performing this analysis for both node-positive patients and for those without lymph node metastases demonstrated a different prognostic meaning of the variables. The combination of each of the group-specific variables led to a prognostic factor, which allowed an assignment of patients to several subgroups with significantly different risk for distant metastases. Thus, both a low-risk group of node-negative patients with a 5-year distant recurrence rate of only 5.8%, and a higher risk group of node-negative patients with a recurrence rate of 38.6% could be identified. Among the node-positive patients, a low-risk group with a distant recurrence rate of 8.6%, and also a high risk group with 69% distant recurrence, could be identified.     

Flow cytometric detection of multifocal DNA aneuploid cell populations in mastectomy specimens containing a primary breast carcinoma

DNA flow cytometry was used to study the presence of DNA aneuploid cell populations in macroscopically normal glandular tissue in mastectomy specimens from 30 patients with breast cancer. In the 13 patients with a DNA diploid primary tumor, no DNA aneuploidy could be found in any of the 39 distant specimens assessed. However, DNA aneuploid cell populations were demonstrated in four of the 17 (23%) patients with a primary DNA aneuploid carcinoma and in seven out of 54 (13%) distant tissue samples (P = 0.02). In all cases the DNA index of the DNA aneuploid cells found in the distant samples was identical to that of the primary tumor. The replicate aneuploid DNA indices and histologic controls taken in parallel very strongly suggest that these distant DNA aneuploid cell populations are metastases.     

Claudin-2 promotes breast cancer liver metastasis by facilitating tumor cell interactions with hepatocytes

We previously identified claudin-2 as a functional mediator of breast cancer liver metastasis. We now confirm that claudin-2 levels are elevated in liver metastases, but not in skin metastases, compared to levels in their matched primary tumors in patients with breast cancer. Moreover, claudin-2 is specifically expressed in liver-metastatic breast cancer cells compared to populations derived from bone or lung metastases. The increased liver tropism exhibited by claudin-2-expressing breast cancer cells requires claudin-2-mediated interactions between breast cancer cells and primary hepatocytes. Furthermore, the reduction of the claudin-2 expression level, either in cancer cells or in primary hepatocytes, diminishes these heterotypic cell-cell interactions. Finally, we demonstrate that the first claudin-2 extracellular loop is essential for mediating tumor cell-hepatocyte interactions and the ability of breast cancer cells to form liver metastases in vivo. Thus, during breast cancer liver metastasis, claudin-2 shifts from acting within tight-junctional complexes to functioning as an adhesion molecule between breast cancer cells and hepatocytes.     

Comparison of nuclear DNA content in primary and metastatic malignant melanoma.

The DNA patterns obtained from 23 primary malignant melanomas and 35 corresponding metastases were compared and found to differ in many cases. In eight cases the primary tumors and their metastases had a ploidy type I ("euploid") DNA pattern. One case had a type I primary tumor and both type I and type II metastases. Five cases had type I primary tumors and ploidy type II ("aneuploid") DNA pattern metastases. In five cases the primary tumors and corresponding metastases were type II, and in another four cases the primary tumors were type II, whereas the metastases were type I. We interpret these data as indicating that malignant melanomas (more often than adenocarcinomas) are composed of genetically heterogeneous tumor sublines that frequently give rise to heterogeneously composed metastases. Since we sometimes observed a change in the DNA content in malignant melanomas, it seems to be more difficult to obtain prognostic information from DNA analysis in malignant melanoma as compared to the more stable adenocarcinomas.     

Multiple mutations of the p53 gene in human mammary carcinoma

Alteration of the p53 tumor suppressor gene is the most common genetic abnormality in human cancer. In breast cancer, depending on the stage of disease and method of detection, mutation rates of 25-60% have been observed. Multiple mutations of p53 gene in the same tumor however, are rarely reported. In this study we explored the frequency of multiple mutations of p53 gene in mammary carcinoma in a cohort of south Florida patients. Three hundred eighty-four cases of primary breast cancer diagnosed between 1984 and 1986 at the University of Miami, Jackson Medical Center were subjects of this study. Sequence analysis of exons 5 through 8 of p53 was performed on cloned PCR-amplified DNA of formalin-fixed, paraffin-embedded tumors. Two hundred thirty-four of 384 breast cancers (61%) had p53 mutation. Of those, 36 tumors showed more than one mutation; 31 tumors had two mutations, three showed three, one tumor had five mutations, and one case carried six mutations. The majority of mutations were missense (43) followed by silent (35); and most occurred within a single exon. Our study suggests that multiple mutations of p53 suppressor gene in breast cancer are more common than currently believed.     

A Mouse Tumor Model of Surgical Stress to Explore the Mechanisms of Postoperative Immunosuppression and Evaluate Novel Perioperative Immunotherapies

Surgical resection is an essential treatment for most cancer patients, but surgery induces dysfunction in the immune system and this has been linked to the development of metastatic disease in animal models and in cancer patients. Preclinical work from our group and others has demonstrated a profound suppression of innate immune function, specifically NK cells in the postoperative period and this plays a major role in the enhanced development of metastases following surgery. Relatively few animal studies and clinical trials have focused on characterizing and reversing the detrimental effects of cancer surgery. Using a rigorous animal model of spontaneously metastasizing tumors and surgical stress, the enhancement of cancer surgery on the development of lung metastases was demonstrated. In this model, 4T1 breast cancer cells are implanted in the mouse mammary fat pad. At day 14 post tumor implantation, a complete resection of the primary mammary tumor is performed in all animals. A subset of animals receives additional surgical stress in the form of an abdominal nephrectomy. At day 28, lung tumor nodules are quantified. When immunotherapy was given immediately preoperatively, a profound activation of immune cells which prevented the development of metastases following surgery was detected. While the 4T1 breast tumor surgery model allows for the simulation of the effects of abdominal surgical stress on tumor metastases, its applicability to other tumor types needs to be tested. The current challenge is to identify safe and promising immunotherapies in preclinical mouse models and to translate them into viable perioperative therapies to be given to cancer surgery patients to prevent the recurrence of metastatic disease.     

Long-term follow-up of patients treated with radical surgery for rectal cancer

In developed societies colorectal cancer (CRC) is the second most frequent malignant tumor which causes more than 5000 deaths yearly in Hungary. We have attempted to answer the question how to improve the above mentioned data by the long-term follow-up of patients operated upon for rectal cancer at our department. Of the patients operated on for rectal cancer at our department between March 1990 and April 2006, we have conducted regular follow-up of 297 patients according to a protocol developed by us. We have examined the length of time between the rectum operation and the diagnosis and the number of local recurrences, distant metastases, tumor progression in more than one organ as well as second tumors (independent of the rectal cancer). During this period we found 24 local recurrences, 32 distant metastases, 43 tumor progressions in more than one organ, and 21 second tumors. In two patients, in addition to distant metastases, we found a second CRC independent of the original rectal cancer, and in one patient with tumor progression in more than one organ we also detected breast cancer. In one patient we found 3 second tumors (CR, lung and urinary bladder) independent of the original rectal cancer. Altogether we found tumors in 117 out of 297 patients. During the same period, we performed 69/117 operations and 31/117 patients were alive at the end of our study with a median survival of 60.4 (3-184) months. In summary, we can state that this work is beneficial for curing the recurrence of rectal cancer, making the patients' life longer or making the quality of life better for the patients operated on for rectal cancer.     

Flow cytometric analysis of DNA stemline heterogeneity in primary and metastatic breast cancer.

Flow cytometric DNA-ploidy analysis was used to investigate intratumor DNA stemline heterogeneity in primary breast carcinomas and lymph node metastases (LNM). The study was done in tumor specimens from 44 patients 35 of whom had LNM. In all, measurements were done in 214 different samples of primary tumors and 211 lymph nodes. Sixty-one percent (27/44) of the primary tumors were found to have multiple DNA aneuploid stemlines when the data of the separate samples per tumor (mean 4.9) were compared. Only five of 44 (11%) primary tumors were DNA diploid; two of these had DNA aneuploid metastases. Statistical analysis of these results indicated that, on average, four samples are needed for reliable determination of the DNA ploidy status of primary tumors by flow cytometry. In the majority of the cases (26/35), distinct tumor DNA stemlines found in LNM were also present in the primary tumor, which suggests that the generation of DNA ploidy diversity may have taken place prior to metastasis. Multiploidy was not related to tumor size but, particularly for LNM, was significantly correlated with age (r = 0.40, P = 0.02). The results of this study support the view that breast cancer is an extremely heterogeneous disease and that underestimation of this factor might account for the disagreement in literature about the prognostic value of DNA ploidy determinations.     

Human small breast epithelial mucin: the promise of a new breast tumor biomarker

Breast cancer remains one of the most frequently diagnosed cancers today. In developed countries, one in eight women is expected to present with breast cancer within her lifetime and an estimated 1,000,000 cases are detected each year worldwide (Canadian Cancer Statistics, http://www.cancer.ca/vgn/images/ portal/cit_86751114/14/33/1959864 11niw_stats2004_en.pdf). For women with recurrent disease, the median time of survival is about 2 years. Despite optimal surgery, adjuvant irradiation, hormonal treatment, and chemotherapy, approximately 30% of patients with localized breast cancer finally develop distant metastases. Early detection, which enables intervention at a localized and potentially curable stage, remains a central goal in breast cancer treatment. Indeed, the 5-year survival rate for women with breast cancer has been shown to increase dramatically when the disease is diagnosed at an early stage: from less than 25% in women with disseminated cancer to about 75% in patients with regional disease and over 95% in women with a localized tumor (Breast Cancer Facts and Figures, 2001-2002, http://www.cancer.org/downloads/STT/BrCaFF 2001.pdf). Unfortunately, only 60% of all breast cancers are diagnosed at a local stage. Any improvement in early detection through identification of tumor biomarkers would have a significant impact on reducing overall breast cancer mortality.     

乳腺癌双膦酸盐辅助治疗临床研究进展

乳腺癌是女性发病率和死亡率最高的恶性肿瘤,复发和远处转移仍是导致患者死亡的首位原因,而双膦酸盐作为一种骨质吸收抑制剂,能够抑制破骨细胞介导的骨质吸收,在多种实体肿瘤骨转移及多发性骨髓瘤等恶性疾病所致的骨相关事件治疗中起重要作用。近年来大量体外、体内实验表明双膦酸盐还具有抑制肿瘤细胞生长、粘附、播散和侵润,降低肿瘤细胞膜稳定性、促进肿瘤细胞凋亡等直接抗肿瘤作用以及抑制肿瘤血管生成、激活免疫细胞对肿瘤细胞的杀伤等间接抗肿瘤作用,基于这些基础研究结果已经开展了一系列针对双膦酸盐辅助治疗乳腺癌的,陆床试验研究,本文就近年相关临床试验研究进展做简要综述。     

Application of DNA flow cytometry to paraffin-embedded archival material for the study of aneuploidy and its clinical significance

By using a recently developed flow cytometric method we have analyzed cellular DNA content of paraffin-embedded histological material from cancer patients. This method allows the retrospective study of tumors from patients whose clinical outcome is already known, and we have applied it to ovarian cancers, stage II breast cancers, and to metastatic adenocarcinoma of unknown primary site. In addition to knowledge of patient survival, comprehensive information was available about other prognostic determinants and treatment received, and we have used multivariate analysis in an attempt to determine the prognostic significance of cellular DNA content. In ovarian cancer, it is a major prognostic variable except in stage IV disease, whereas in metastatic adenocarcinoma of unknown primary site cellular DNA content has no influence on survival. For stage II breast cancer the situation is more complex and requires larger numbers to be studied. However, aneuploid tumors tend to have more extensive involvement of axillary lymph nodes and a poorer overall disease-free survival. This influence of DNA content on disease-free survival appears to be confined to premenopausal patients, and has no effect on patient survival following disease recurrence. Although we need to study more patients and more tumor types, taken together the results so far show a generally more favorable prognosis for patients with diploid tumors, except in the presence of recurrent or metastatic disease. The better prognosis associated with diploid tumors could be due to the fact that they are more commonly found in earlier clinical stages rather than to their being inherently less aggressive than aneuploid tumors.