B16 melanoma variants selected by one or more cycles of spontaneous metastasis to the same organ fail to exhibit organ specificity

Metastatic clones of the mouse B16 melanoma spontaneously disseminate from subcutaneous tumors throughout the body in two stages, initially to the lungs and secondarily from established lung metastases to systemic sites. From the heterogeneous parent B16 melanoma cell line and from two representative clones, G3.5 and G3.12, cell populations were selected after one or more cycles of tumor growth or metastasis to a particular site, to determine whether metastatic variants with greater organ preference or specificity could be generated. Variants with enhanced secondary metastatic activity were obtained only from G3.12 tumor-disseminated metastases growing in the lungs or in systemic organs. Regardless of the organ of selection or the number of selection cycles, all variants exhibited an overall increase in secondary metastasis incidence and burden in the brain, adrenals, kidneys and ovaries, but no organ preference or specificity was obtained. Populations that grew especially well in the brain, ovaries or liver following intravascular injection were either non-metastatic or exhibited no organ preference during spontaneous metastasis. The increased secondary metastatic activity of G3.12 variants was apparently not due to either longer host survival or to tumor-disseminated cells bypassing the lungs, but may result from enhanced growth potential or greater secondary dissemination capability imparted during growth as lung metastases.     

A unique allogenic model of metastatic pheochromocytoma: PC12 rat pheochromocytoma xenografts to nude mice and establishment of metastases-derived PC12 variants

Local invasion and metastatic spread to distant sites are major causes of death in patients with malignant pheochromocytoma. Since appropriate in vivo models do not exist, little is known about the underlying mech-anisms of tumor growth and invasion. We, therefore, developed an animal model of malignant pheochromo-cytoma and established organotropic metastatic variants of PC12 rat pheochromocytoma cells. PC12 cells were established as xenografts to BALB/c NCR-NU mice. Subsequent to development of tumors or metas-tases, primary cultures from local tumors, metastases to lymph nodes, lungs and liver were established. These were subcultured in vitro and reinjected for up to five successive in vivo/in vitro cycles. Xenografted PC12 cells grew tumors with a doubling time of 6.78 ± 0.58 days during log phase of tumor growth, killing hosts within 5-12 weeks depending on the experimental conditions. Tumors reproducibly metastasized to lymph nodes and the lung. Spontaneous metastases to the liver were not observed, but were achieved by intrasplenic injection of parent PC12 cells. In vitro, the metastatic cell lines displayed striking differences in morphology, overall growth patterns and nutritional requirements as well as binding to purified extracellular matrix pro-teins compared to the parent cell line. In vivo, the metastatic variants showed marked enhancement of metastatic ability. This is the first report of PC12 rat pheochromocytoma cells to exhibit the malignant phe-notype in vivo. We also established variant PC12 cell lines that preferentially metastasized to specific sites and that had acquired different in vitro behavior and ability to metastasize. This unique model system should be useful for further studies relating to the invasion and metastases of pheochromocytoma and may prove valuable for investigations of novel antineoplastic therapies in vitro and in vivo. © Rapid Science Ltd.     

The integrin alpha 6 beta 1 promotes the survival of metastatic human breast carcinoma cells in mice.

The role of the integrin alpha 6 beta 1 in breast carcinoma progression was studied by targeted elimination of this integrin in MDA-MB-435 cells, a human breast carcinoma cell line that is highly metastatic in athymic mice. The strategy used is based on the finding that expression of a cytoplasmic domain deletion mutant of the beta 4-integrin subunit (beta 4-delta CYT) in MDA-MB-435 cells eliminates formation of the alpha 6 beta 1 heterodimer. MDA-MB-435 cells that lacked alpha 6 beta 1 expression (beta 4-delta CYT transfectants) formed tumors in athymic mice that were suppressed in their growth and that exhibited a significant increase in apoptosis in comparison to the control tumors. Unlike the control MDA-MB-435 cells, the beta 4-delta CYT transfectants were unable to establish metastatic foci in the lungs. Also, the control transfectants grew substantially better than the beta 4-delta CYT transfectants in the liver after intrahepatic injection because of extensive apoptosis in the beta 4-delta CYT transfectants. These data suggest that a major function of the alpha 6 beta 1 integrin in breast carcinoma is to facilitate tumorigenesis and promote tumor cell survival in distant organs.     

Metastatic behavior of human breast carcinomas overexpressing the Bcl-x(L) gene: a role in dormancy and organospecificity

The ability of metastatic cells to survive antiapoptotic signals may contribute to the organospecific-spread patterns of clinical metastasis and dormancy. MDA-MB-435 breast cancer cells (435/Bcl-x(L)), which overexpress the Bcl-x(L) gene, were labeled with the luciferase gene and injected orthotopically into homozygous athymic Balb/c (nude) mice to study the metastatic behavior of the breast cancer cells. The overexpression of Bcl-x(L) in tumors increased the overall metastatic burden in mice (bones, liver, kidneys, brain, lungs, and lymph nodes) in comparison with control tumors (435/NEO:luc) during the same time interval (ANOVA, p = 0.005). The principal differences after 110 days were found in bones, which had 1.5 x 10(5) +/- 1.2 x 10(5) tumor cell equivalents (p = 0.03), and lymph nodes, which had 7.0 x 10(6) +/- 6.0 x 10(6) tumor cell equivalents (p = 0.08). The analyses of light production by tissues at different times showed that cells from 435/NEO:luc and 435/Bcl-x(L).luc tumors were detectable in several organs by the second day after intramammary fat pad implantation. Although initially arriving at the target organs in similar numbers, 435/Bcl-x(L) cells developed more metastases than 435/Neo cells, indicating that the Bcl-x(L) gene might have a role in breast cancer dormancy, promoting survival of cells in metastatic foci. Thus, we suggest that overexpression of Bcl-x(L) could counteract the proapoptotic signals in the microenvironment and favor the successful development of metastasis in specific organs.     

Dormant cancer cells retrieved from metastasis-free organs regain tumorigenic and metastatic potency

This study shows that solitary, dormant human cancer cells, retrieved from metastasis-free organs of animals carrying spontaneously metastatic primary tumors, can reactivate their tumorigenic and metastatic potency. The tumors were produced by MDA-MB-435 CL16 breast cancer cells permanently labeled with green fluorescent protein and the neomycin resistance gene. This enabled unequivocal identification of tumor cells emerging from organ explants cultured in neomycin to eliminate nonneoplastic host cells. Rescued cells resumed proliferation and generated lines that were tumorigenic and metastatic in fresh animals. All resulting primary and secondary tumors were uniformly labeled. Cells recovered from bone marrows and spleens, where there were no metastases, were as tumorigenic and metastatic as cells recovered from lungs and lymph nodes, which are the preferred sites of colonization for this tumor line. This evidence that malignant growth of disseminated cancer cells is suspended indefinitely by microenvironmental conditions in metastasis-free organs, although it is still active in others of the same host, shows that neoplastic progression can be arrested and has far-reaching biological and clinical implications. Specifically, it predicts the existence of natural, nonimmune host mechanisms that stimulate or inactivate tumor growth in different anatomical sites, which may be exploitable for therapeutic benefit.     

Targeting and utilizing primary tumors as live vaccines: changing strategies

Tumor metastases and relapse are the major causes of morbidity and mortality in cancer. Although surgery, chemotherapy and/or radiation therapy can typically control primary tumor growth, metastatic and relapsing tumors are often inaccessible or resistant to these treatments. An adaptive immune response can be generated during these conventional treatments of the primary tumor, and presumably both the primary tumor and secondary metastases share many of the same or similar antigenic characteristics recognized by the immune system. Thus, when established, this response should be able to control metastatic growth and tumor relapse. This review summarizes the mechanisms by which antitumor immune responses are generated, and recent findings supporting the hypothesis that many therapies targeting primary tumors can generate antitumor adaptive immune responses to prevent metastases and tumor relapse.     

Primary leiomyosarcoma of the liver

A 62 year old man developed an abdominal mass, which proved to be a hepatic leiomyosarcoma. During the subsequent two years he lost about 40 pounds. At autopsy the liver weighed 11,200 grams and was almost entirely replaced by tumor nodules. Small metastatic nodules were found in the lungs, pancreas, thyroid, adrenals, and kidneys. This appears to be the eighth case of primary smooth muscle tumor of the liver to have been reported. Primary smooth muscle tumors of the liver progress relatively slowly, even if they are histologically malignant.     

Comparative study of the distribution of 7,12-dimethylbenz(a)anthracene in pregnant rats and their fetuses

On the 21st day of pregnancy rats were given an intravenous injection of 7,12-dimethylbenz(a)anthracene (DMBA) in a dose of 15 mg/kg, and its concentration in the organs of the mothers (liver, kidneys, lungs, brain, spleen, and placenta) and of their fetuses (liver, kidneys, lungs, brain, intestine, carcass, and whole fetus) was determined by a fluorescence-spectral method 30, 60, and 180 min later. The highest concentration of DMBA in the mothers at all times was found in the lungs. With an increase in the time of injection the DMBA concentration fell in all organs of the pregnant rats, except in the brain, in which it rose. In the fetuses an irregular distribution of the carcinogen in the organs was found only 60 min after injection of DNBA, when the highest concentration was detected in the liver. In all fetal organs the maximal concentration was found after 60 min. Accumulation of DMBA in the various fetal organs did not correlate with the observed highest frequency of tumors in the kidney and nervous system of rat fetuses following transplacental exposure to DMBA in the same dose.Laboratory of Biophysics and Laboratory of Experimental Tumors, N. N. Petrov Research Institute of Oncology, Ministry of Health of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 3, pp. 334–335, March, 1980.     

结直肠癌原发灶与肝转移灶K-ras基因状态的研究

目的观察K-ras基因在结直肠癌原发灶及肝转移灶的突变状态。方法采用富集PCR配对测序法检测46例（男35例,女11例）结直肠癌肝转移患者原发灶及肝转移灶K-ras基因突变状态,其中结肠癌肝转移21例（45.7%）,直肠癌肝转移25例（54.3%）。结果46例中有18例（39.1%）原发灶K-ras基因为突变型,其中17例对应的肝转移灶K-ras基因为突变型,1例对应的肝转移灶K-ras基因为野生型。28例（60.9%）原发灶K-ras基因为野生型者中,26例对应的肝转移灶K-ras基因为野生型,2例对应的肝转移灶K-ras基因为突变型。统计分析表明,原发灶与肝转移灶K-ras基因突变状况差异无统计学意义（P=1.00）。结论转移性结直肠癌原发灶与肝转移灶的K-ras基因突变状态差异无统计学意义。     

Effect of host microenvironment on the microcirculation of human colon adenocarcinoma.

It is generally accepted that the host microenvironment influences tumor biology. There are discrepancies in growth rate, metastatic potential, and efficacy of systemic treatment between ectopic and orthotopic tumors. Liver is the most common and critical site of distant metastasis of colorectal carcinoma. Tumorigenicity and efficacy of chemotherapeutic agents in colorectal tumors are different in liver and subcutaneous sites. Thus, we hypothesize that the liver (orthotopic) versus subcutaneous (ectopic) microenvironment would have different effects on the angiogenesis and maintenance of the microcirculation of colorectal tumor. To this end, we developed a new method to monitor and to quantify microcirculatory parameters in the tumor grown in the liver. Using this approach, we compared the microcirculation of LS174T, a human colon adenocarcinoma, metastasized to the liver with that of the host liver vessels and that of the same tumor grown in the subcutaneous space. In the liver metastasis model, 5 x 10(6) LS174T cells were injected into the spleen of nude mice. Four to eight weeks later, the liver with metastatic tumors was exteriorized and placed on a special stage and observed under an intravital fluorescence microscope. The dorsal skinfold chamber model was used to study the subcutaneous tumors. Red blood cell velocity, vessel diameter, density, permeability, and leukocyte-endothelial interactions were measured using fluorescence microscopy and image analysis. Vascular endothelial growth factor/ vascular permeability factor (VEGF/VPF) mRNA expression was determined by the Northern blot analysis. LS174T tumor foci in the liver had tortuous vascular architecture, heterogeneous blood flow, significantly lower vascular density, and significantly higher vascular permeability than normal liver tissue. Tumors grown in the liver had significantly lower vessel density, especially in the center coincident with central necrosis, than the subcutaneous tumors. The frequency distribution of vessel diameters of liver tumor was slightly shifted to smaller size compared with that of subcutaneous tumor. Leukocyte rolling in liver tumor was twofold lower than that in subcutaneous tumor. These physiological findings were consistent with the measurement of VEGF/VPF in that the VEGF/VPF mRNA level was lower in the liver tumor than that in the subcutaneous tumor. However, macromolecular vascular permeability in the liver tumor was significantly higher than in the subcutaneous tumor. Liver sinusoidal endothelial cells, the origin of liver tumor vessel endothelium, are known to be fenestrated and not to have a basement membrane, suggesting that the difference in endothelial cell origin may explain the difference in tumor vascular permeability in two sites. These findings demonstrate that liver microenvironment has different effects on some aspects of the tumor angiogenesis and microcirculation compared with the subcutaneous tissues. The new model/method described in this paper has significant implications in two research areas: 1) the liver microenvironment and its effect on tumor pathophysiology in conjunction with cytokine/ growth factor regulation and 2) the delivery of drugs, cells, and genes to liver tumors.     

Organ-specificity of the extravasation process: An ultrastructural study

The process of extravasation of the high metastatic Lewis lung carcinoma line was examined in different organs. Four of the five organs (liver, lungs, brain and adrenals) represent the most frequent metastatic sites in humans. In the case of each organ 150–350 tumor cells were analysed. The interaction of tumor cells with endothelial cells and the basement membrane showed significant differences between the organs. In the liver and lungs, endothelial cells were found to migrate onto the surface of the tumor cells, resulting in the removal of tumor cells from the circulation. The process was initiated by development of cytoplasmic projections on the luminal surface of the endothelial cells. In the liver only half of the tumor cells showed basement membrane degradation even after 24 h, although 6 h after injection 40% of the tumor cells were sequestered from the circulation. In the adrenals and brain, tumor cells were not covered by endothelial cells instead, limited retraction of endothelial cells was followed by penetration of the basement membrane. In the kidney both types of tumor cell-endothelial cell interactions were observed, but the process of extravasation was not completed, stopping as the tumor cells reached the basement membrane or the mesangial matrix. The time course of tumor cell extravasation also showed significant differences between the organs. The process was most rapid in case of the liver and adrenals. By 6 h 40–50% of the tumor cells were in the process of extravasation or were in an extracapillary position. These organs are preferential metastatic sites of this tumor line. The time of extravasation was much longer in the other organs (lungs 16 h, brain 48 h), for which this tumor line shows no preference. Conclusions: (1) Type and duration of tumor cell extravasation differ between the organs. (2) The time needed to reach extraluminal position, but not the type of extravasation correlates with the organ preference. (3) Endothelial cells of the lungs and liver can play a much more active role in the process of extravasation than previously suggested. (4) Tumor cells can complete the metastatic process without reaching a complete extracapillary position; contact with the basement membrane or extracellular matrix seems to be sufficient. This revised version was published online in July 2006 with corrections to the Cover Date.     

Organ distribution of experimental metastases of a human colorectal carcinoma injected in nude mice

The metastatic behavior of the HT-29 human colorectal carcinoma cell line was studied following injection into nude mice by different routes. After intrasplenic injection, experimental metastases formed in the livers of most mice. Variant lines were established in culture from the liver lesions and from tumors growing at the site of injection, the spleen. Cells of the HT-29 LMM line exhibited slightly enhanced ability to form liver metastases compared with cells of the non-selected parent line. When injected i.v., the HT-29 cells produced only a few small experimental metastases in the lungs, but in most of the mice macroscopic tumors were found in various lymph nodes and the interscapular fat. Analyses of the distribution of IdUrd-labeled cells did not reveal a preferential localization of the HT-29 cells in sites where metastases subsequently formed. This suggested that the growth of the human colon carcinoma cells in those sites might be the result of a stimulatory interaction between the tumor and host cells as opposed to growth in sites such as the lungs, where numerous cells arrested after i.v. injection but only a few, small metastases were seen 60 days later.     

A BALB/c murine lung alveolar carcinoma used to establish a surgical spontaneous metastasis model

Line-1, a weakly immunogenic lung tumor cell line derived from the BALB/c mouse, metastasizes spontaneously to the lungs of mice following subcutaneous administration. The parameters that influence metastasis as well as the progression of metastatic lung disease following surgical resection of primary subcutaneous tumors were characterized. Histological analysis of the lungs obtained from mice bearing different size subcutaneous tumors demonstrated that >90% of the mice developed micrometastatic disease in the lungs when the tumor exceeded 650 mm3 in size. Surgical resection of subcutaneous tumors resulted in the cure of primary disease in 95% of the mice. Macroscopic tumor nodules were grossly visible in the lungs of 75% of the mice 5 weeks after surgery. Serum amyloid A level correlated with primary tumor burden and was diagnostic for the presence of metastatic disease. The efficiency of metastasis, post-surgical primary tumor recurrence and long-term survival were significantly different between BALB/c mice obtained from different suppliers. The Line-1-BALB/c surgical metastasis model provides a clinically relevant tool for the evaluation of anti-cancer therapies, especially those that are designed to target long-term suppression of minimal residual disease following surgical intervention.     

Altered expression of the retinoblastoma gene product in human sarcomas

BACKGROUND. The retinoblastoma-susceptibility (Rb) gene is a prototype tumor-suppressor gene originally isolated from patients with heritable retinoblastoma. This gene encodes a nuclear phosphoprotein whose expression is altered in several types of human tumors. METHODS. We studied the expression of the Rb protein in 44 primary and 12 metastatic high-grade human sarcomas by means of immunohistochemical methods and Western blotting. Computerized image analysis was used to quantify the level of Rb gene product in individual tumor cells. The expression of the Rb gene was then correlated with clinical outcome in the patients with primary tumors. RESULTS. Of the 44 patients with primary sarcomas, 13 (30 percent) had tumors with normal, homogeneous expression of the Rb protein in essentially all tumor cells. Thirty-one patients with primary tumors (70 percent) had altered Rb expression; in 18 (40 percent) the Rb protein was heterogeneously expressed, and in 13 (30 percent) it was detected in fewer than 20 percent of the tumor cells. All 12 of the patients with metastatic sarcomas had altered expression of the Rb protein. When the findings in the patients with primary tumors were correlated with clinical outcome, survival was found to be significantly increased in the patients whose tumors had homogeneous Rb expression, as compared with those with either heterogeneous expression (P = 0.026) or no expression (P = 0.012). CONCLUSIONS. Tumors in which the expression of Rb gene product was decreased were more aggressive than tumors in which this protein was expressed by nearly all cells. The Rb gene product may be an important prognostic variable in patients with these tumors.     

Characterization of an animal model of aggressive metastatic pheochromocytoma linked to a specific gene signature

Pheochromocytomas are chromaffin cell-derived neuroendocrine tumors. There is presently no cure for metastatic pheochromocytoma and no reliable way to distinguish malignant from benign tumors before the development of metastases. In order to successfully manage pheochromocytoma, it is necessary to better understand the biological determinants of tumor behavior. For this purpose, we have recently established a mouse model of metastatic pheochromocytoma using tail vein injection of mouse pheochromocytoma (MPC) cells. We optimized this model modifying the number of cells injected, length of trypsin pre-treatment, and incubation temperature and duration for the MPC cells before injection, and by serial passage and re-selection of tumors exhibiting the metastatic phenotype. We evaluated the effect of these modifications on tumor growth using serial in vivo Magnetic Resonance Imaging studies. These results show that number of cells injected, the pre-injection incubation temperature, and duration of trypsin treatment are important factors to produce faster growing, more aggressive tumors that yielded secondary metastatic lesions. Serial harvest, culture and re-selection of metastatic liver lesions produced even more aggressive pheochromocytoma cells that retained their biochemical phenotype. Microarray gene expression comparison and quantitative real-time PCR of these more aggressive cells to the MPC-parental cell line identified genes that may be important for the metastatic process. Lucia Martiniova and Edwin W. Lai contributed equally to this work.     

Postmortem pathology of opportunistic infection in a HIV positive patient--a case report

An autopsy case of HIV positive patient with multiple opportunistic infections is described. We received heart, lungs, spleen and both the kidneys along with pieces of cerebrum for anatomy and histopathological examination. Histology of organs revealed disseminated non-granulomatous necrotizing type of tissue reaction with superadded infection with Cryptococcus neoformans (C. neoformans) in liver and brain. Pneumocysts carini (P. carini) induced pneumonia in lungs, disseminated mycobacterial infection in spleen, lungs, liver and kidneys and acute fibrinous meningitis with superadded infection with C. neoformans in brain. Special stains were carried out to demonstrate different organisms.     

Human neural stem cell tropism to metastatic breast cancer

Metastasis to multiple organs is the primary cause of mortality in breast cancer patients. The poor prognosis for patients with metastatic breast cancer and toxic side effects of currently available treatments necessitate the development of effective tumor-selective therapies. Neural stem cells (NSCs) possess inherent tumor tropic properties that enable them to overcome many obstacles of drug delivery that limit effective chemotherapy strategies for breast cancer. We report that increased NSC tropism to breast tumor cell lines is strongly correlated with the invasiveness of cancer cells. Interleukin 6 (IL-6) was identified as a major cytokine mediating NSC tropism to invasive breast cancer cells. We show for the first time in a preclinical mouse model of metastatic human breast cancer that NSCs preferentially target tumor metastases in multiple organs, including liver, lung, lymph nodes, and femur, versus the primary intramammary fat pad tumor. For proof-of-concept of stem cell-mediated breast cancer therapy, NSCs were genetically modified to secrete rabbit carboxylesterase (rCE), an enzyme that activates the CPT-11 prodrug to SN-38, a potent topoisomerase I inhibitor, to effect tumor-localized chemotherapy. In vitro data demonstrate that exposure of breast cancer cells to conditioned media from rCE-secreting NSCs (NSC.rCE) increased their sensitivity to CPT-11 by 200-fold. In vivo, treatment of tumor-bearing mice with NSC.rCE cells in combination with CPT-11 resulted in reduction of metastatic tumor burden in lung and lymph nodes. These data suggest that NSC-mediated enzyme/prodrug therapy may be more effective and less toxic than currently available chemotherapy strategies for breast cancer metastases.     

LIM kinase inhibition reduces breast cancer growth and invasiveness but systemic inhibition does not reduce metastasis in mice

Metastasis is the major cause of morbidity and mortality in cancer patients. An understanding of the genes that regulate metastasis and development of therapies to target these genes is needed urgently. Since members of the LIM kinase (LIMK) family are key regulators of the actin cytoskeleton and are involved in cell motility and invasion, LIMK is considered to be a good therapeutic target for metastatic disease. Here we investigated the consequences of LIMK inhibition on growth and metastasis of human and mouse mammary tumors. LIMK activity was reduced in tumor cells by expression of dominant-negative LIMK1, by RNA interference or with a selective LIMK inhibitor. The extent of phosphorylation of the LIMK substrate, cofilin, of proliferation and invasion in 2D and 3D culture and of tumor growth and metastasis in mice were assessed. Inhibition of LIMK activity efficiently reduced the pro-invasive properties of tumor cells in vitro. Tumors expressing dominant-negative LIMK1 grew more slowly and were less metastatic in mice. However, systemic administration of a LIMK inhibitor did not reduce either primary tumor growth or spontaneous metastasis. Surprisingly, metastasis to the liver was increased after administration of the inhibitor. These data raise a concern about the use of systemic LIMK inhibitors for the treatment of metastatic breast cancer.     

Assessing Tumor Growth and Distribution in a Model of Prostate Cancer Metastasis using Bioluminescence Imaging

Bioluminescence imaging (BLI) has greatly facilitated the development of animal models of cancer, allowing sensitive detection of luciferase-expressing cancer cells in living mice. Previous efforts characterizing such models have involved small numbers of animals, limiting understanding of their performance features. We employed BLI to serially image the growth and distribution of a prostate cancer cell line, 22Rv1, after intracardiac injection into scid mice (n = 85). This approach models hematogenous dissemination of cancer cells and allows inquiry of the process of metastatic colonization at various organ sites, although accurately injecting cancer cells into the left ventricle remains challenging. Therefore, to predict injection success we measured the ratio of the thoracic bioluminescence signal to the whole body bioluminescence signal (T/WB ratio) immediately following intracardiac injection. A T/WB ratio less than 0.50 predicted the development of tumors outside of the thoracic cavity while a T/WB greater than 0.50 predicted the development of tumors entirely within the thoracic cavity, suggestive of a failed injection. Progressive tumor growth was quantified using BLI. Tumors colonized multiple organ sites including bone, liver, and adrenal glands resembling the spectrum of metastases in autopsy studies of patients with prostate cancer. Tumors growing in bone exhibited mixed osteolytic and osteoblastic features, eliciting a spiculated periosteal response. With the ability to more accurately predict injection success, we can now monitor efficacy of intracardiac injections facilitating the performance of this model.