cancer metastasis

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WordNet

1. type genus of the family Cancridae (同)genus Cancer
2. the fourth sign of the zodiac; the sun is in this sign from about June 21 to July 22 (同)Cancer the Crab, Crab
3. (astrology) a person who is born while the sun is in Cancer (同)Crab
4. a small zodiacal constellation in the northern hemisphere; between Leo and Gemini
5. any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream (同)malignant neoplastic disease
6. the spreading of a disease (especially cancer) to another part of the body

PrepTutorEJDIC

1. 〈U〉〈C〉『がん』 / 〈U〉〈C〉害悪 / 《Cancer》(星座の)カニ座
2. (癌(がん)などの)転移

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/06/11 03:40:14」(JST)

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For the musical composition, see Metastaseis (Xenakis). For the 2009 film, see Metastases (film). For the Spanish-language remake of Breaking Bad, see Metástasis.

Metastasis
Illustration showing hematogeneous metastasis
Classification and external resources
Specialty	Oncology
DiseasesDB	28954
MedlinePlus	002260

Metastasis, or metastatic disease, is the spread of a cancer or other disease from one organ or part of the body to another not directly connected with it. The new occurrences of disease thus generated are referred to as metastases /mə ˈtæs tə siːz/ (sometimes abbreviated "mets"). Metastasis is a Greek word meaning "displacement", from μετά, meta, "next", and στάσις, stasis, "placement".

Cancer occurs after a single cell in a tissue is progressively genetically damaged to produce cells with uncontrolled proliferation. This uncontrolled proliferation by mitosis produces a primary heterogeneic tumour. The cells which constitute the tumor eventually undergo metaplasia, followed by dysplasia then anaplasia, resulting in a malignant phenotype. This malignancy allows for invasion into the circulation, followed by invasion to a second site for tumorigenesis.

Some cancer cells acquire the ability to penetrate the walls of lymphatic and/or blood vessels, after which they are able to circulate through the bloodstream (circulating tumor cells) to other sites and tissues in the body. This process is known (respectively) as lymphatic or hematogenous spread. After the tumor cells come to rest at another site, they re-penetrate the vessel or walls and continue to multiply, eventually forming another clinically detectable tumor. This new tumor is known as a metastatic (or secondary) tumor. Metastasis is one of the "Hallmarks of Cancer", distinguishing it from benign tumors. Most neoplasms can metastasize, although in varying degrees (e.g., basal cell carcinoma rarely metastasize).

When tumor cells metastasize, the new tumor is called a secondary or metastatic tumor, and its cells are similar to those in the original or primary tumor. This means, for example, that, if breast cancer metastasizes to the lungs, the secondary tumor is made up of abnormal breast cells, not of abnormal lung cells. The tumor in the lung is then called metastatic breast cancer, not lung cancer. Metastasis is a key element in cancer staging systems such as the TNM staging system, where it represents the "M". In Overall Stage Grouping metastasis places a cancer in Stage IV. The possibilities of curative treatment are greatly reduced, or often entirely removed, when a cancer has metastasized.

Signs and symptoms

Cut surface of a liver showing multiple paler metastatic nodules originating from pancreatic cancer

Initially, nearby lymph nodes are struck early. The lungs, liver, brain, and bones are the most common metastasis locations from solid tumors.

• In lymph nodes, a common symptom is lymphadenopathy
• Lungs: cough, hemoptysis and dyspnea (shortness of breath)
• Liver: hepatomegaly (enlarged liver), nausea and jaundice
• Bones: bone pain, fracture of affected bones
• Brain: neurological symptoms such as headaches, seizures, and vertigo.

Although advanced cancer may cause pain, it is often not the first symptom.

Some patients, however, do not show any symptoms. When the organ gets a metastatic disease it begins to shrink until its lymph nodes burst, or undergo lysis.

Pathophysiology

Metastatic tumors are very common in the late stages of cancer. The spread of metastasis may occur via the blood or the lymphatics or through both routes. The most common places for the metastases to occur are the lungs, liver, brain, and the bones.

Factors involved

Metastasis is a complex series of steps in which cancer cells leave the original tumor site and migrate to other parts of the body via the bloodstream, the lymphatic system, or by direct extension. To do so, malignant cells break away from the primary tumor and attach to and degrade proteins that make up the surrounding extracellular matrix (ECM), which separates the tumor from adjoining tissues. By degrading these proteins, cancer cells are able to breach the ECM and escape. The location of the metastases is not always random, with different types of cancer tending to spread to particular organs and tissues at a rate that is higher than expected by statistical chance alone. Breast cancer, for example, tends to metastasize to the bones and lungs. This specificity seems to be mediated by soluble signal molecules such as chemokines and transforming growth factor beta. The body resists metastasis by a variety of mechanisms through the actions of a class of proteins known as metastasis suppressors, of which about a dozen are known.

Human cells exhibit three kinds of motion: collective motility, mesenchymal-type movement, and amoeboid movement. Cancer cells often opportunistically switch between different kinds of motion. Some cancer researchers hope to find treatments that can stop or at least slow down the spread of cancer by somehow blocking some necessary step in one or the other or both kinds of motion.

Cancer researchers studying the conditions necessary for cancer metastasis have discovered that one of the critical events required is the growth of a new network of blood vessels, called tumor angiogenesis. It has been found that angiogenesis inhibitors would therefore prevent the growth of metastases.

Several different cell types are critical to tumor growth. In particular, endothelial progenitor cells have been shown to have a strong influence on the growth of tumor blood vessels. This finding was published in the journals Science (2008) and Genes and Development (2007) together with the fact that endothelial progenitor cells are critical for metastasis and angiogenesis. The importance of endothelial progenitor cells in tumor growth, angiogenesis and metastasis has been confirmed by a recent publication in Cancer Research (August 2010). This seminal paper has demonstrated that endothelial progenitor cells can be marked using the Inhibitor of DNA Binding 1 (ID1). This novel finding meant that investigators were able to track endothelial progenitor cells from the bone marrow to the blood to the tumor-stroma and even incorporated in tumor vasculature. This finding of endothelial progenitor cells incorporated in tumor vasculature proves the importance of this cell type in blood vessel development in a tumor setting and metastasis. Furthermore, ablation of the endothelial progenitor cells in the bone marrow lead to a significant decrease in tumor growth and vasculature development. Therefore, endothelial progenitor cells are very important in tumor biology and present novel therapeutic targets.

NFAT transcription factors are implicated in breast cancer, more specifically in the process of cell motility at the basis of metastasis formation. Indeed, NFAT1 (NFATC2) and NFAT5 are pro-invasive and pro-migratory in breast carcinoma and NFAT3 (NFATc4) is an inhibitor of cell motility. NFAT1 regulates the expression of the TWEAKR and its ligand TWEAK with the Lipocalin 2 to increase breast cancer cell invasion and NFAT3 inhibits Lipocalin 2 expression to blunt the cell invasion.

Epigenetic regulation also plays an important role in the metastatic outgrowth of disseminated tumor cells. Metastases display alterations in histone modifications, such as H3K4-methylation and H3K9-methylation, when compared to matching primary tumors. These epigenetic modifications in metastases may allow the proliferation and survival of disseminated tumor cells in distant organs.

Recently, a series of high-profile experiments suggests that the co-option of intercellular cross-talk mediated by exosome vesicles is a critical factor involved in all steps of the invasion-metastasis cascade. Tumour-derived exosome vesicles harbour prodigious amounts of pathogenic miRNA, mRNA, DNA fragments, proteins as well as oncogenic viral nanoparticles which can enhance cancer metastasis. As summarised by Syn et al., tumour-derived exosomes promote metastasis by 1) providing autocrine and paracrine signals to activate an epithelial-mesenchymal transition (EMT) programme in neoplastic epithelial cells, thus endowing them with the invasive and migratory capabilities; 2) fostering a pre-metastatic niche in secondary organ tissue, where incoming metastatic cells may engraft and colonise; 3) sculpt the immune contexture of the tumour microenvironment and convert reactive, inflammatory stromal infiltrates into accomplices in maligancy.

Routes of metastasis

Main sites of metastases for some common cancer types. Primary cancers are denoted by "...cancer" and their main metastasis sites are denoted by "...metastases".

Metastasis occurs by following four routes:

1. Transcoelomic

The spread of a malignancy into body cavities can occur via penetrating the surface of the peritoneal, pleural, pericardial, or subarachnoid spaces. For example, ovarian tumors can spread transperitoneally to the surface of the liver.

2. Lymphatic spread

Lymphatic spread allows the transport of tumor cells to lymph nodes and ultimately, to other parts of the body. This is the most common route of metastasis for carcinomas. In contrast, it is uncommon for a sarcoma to metastasize via this route. It is worth noting that the lymphatic system does eventually drain into the systemic venous system via the azygous vein, and therefore these metastatic cells can eventually spread through the haematogenous route.

Lymph node with almost complete replacement by metastatic melanoma. The brown pigment is focal deposition of melanin

3. Hematogenous spread

This is typical route of metastasis for sarcomas, but it is also the favored route for certain types of carcinoma, such as those originating in the kidney (renal cell carcinoma). Because of their thinner walls, veins are more frequently invaded than are arteries, and metastasis tends to follow the pattern of venous flow.

4. Transplantation or implantation

Cancer cells may spread to lymph nodes (regional lymph nodes) near the primary tumor. This is called nodal involvement, positive nodes, or regional disease. ("Positive nodes" is a term that would be used by medical specialists to describe a patient's condition, meaning that the patient's lymph nodes near the primary tumor tested positive for malignancy. It is common medical practice to test by biopsy at least two lymph nodes near a tumor site when doing surgery to examine or remove a tumor.) Localized spread to regional lymph nodes near the primary tumor is not normally counted as metastasis, although this is a sign of worse prognosis. Transport through lymphatics is the most common pathway for the initial dissemination of carcinomas.

Organ-specific targets

There is a propensity for certain tumors to seed in particular organs. This was first discussed as the "seed and soil" theory by Stephen Paget over a century ago, in 1889. The propensity for a metastatic cell to spread to a particular organ is termed 'organotropism'. For example, prostate cancer usually metastasizes to the bones. In a similar manner, colon cancer has a tendency to metastasize to the liver. Stomach cancer often metastasises to the ovary in women, then it is called a Krukenberg tumor.

According to the "seed and soil" theory, it is difficult for cancer cells to survive outside their region of origin, so in order to metastasize they must find a location with similar characteristics. For example, breast tumor cells, which gather calcium ions from breast milk, metastasize to bone tissue, where they can gather calcium ions from bone. Malignant melanoma spreads to the brain, presumably because neural tissue and melanocytes arise from the same cell line in the embryo.

In 1928, James Ewing challenged the "seed and soil" theory and proposed that metastasis occurs purely by anatomic and mechanical routes. This hypothesis has been recently utilized to suggest several hypotheses about the life cycle of circulating tumor cells (CTCs) and to postulate that the patterns of spread could be better understood through a 'filter and flow' perspective. However, contemporary evidences indicate that the primary tumour may dictate organotropic metastases by inducing the formation of pre-metastatic niches at distant sites, where incoming metastatic cells may engraft and colonise. Specifically, exosome vesicles secreted by tumours have been shown to home to pre-metastatic sites, where they activate pro-metastatic processes such as angiogenesis and modify the immune contexture, so as to foster a favourable microenvironment for secondary tumour growth.

Metastasis and primary cancer

It is theorized that metastasis always coincides with a primary cancer, and, as such, is a tumor that started from a cancer cell or cells in another part of the body. However, over 10% of patients presenting to oncology units will have metastases without a primary tumor found. In these cases, doctors refer to the primary tumor as "unknown" or "occult," and the patient is said to have cancer of unknown primary origin (CUP) or unknown primary tumors (UPT). It is estimated that 3% of all cancers are of unknown primary origin. Studies have shown that, if simple questioning does not reveal the cancer's source (coughing up blood—"probably lung", urinating blood—"probably bladder"), complex imaging will not either. In some of these cases a primary tumor may appear later.

The use of immunohistochemistry has permitted pathologists to give an identity to many of these metastases. However, imaging of the indicated area only occasionally reveals a primary. In rare cases (e.g., of melanoma), no primary tumor is found, even on autopsy. It is therefore thought that some primary tumors can regress completely, but leave their metastases behind.

Common sites of origin

• Lung
• Breast
• Skin: melanoma (other skin tumors rarely metastasize)
• Colon
• Kidney
• Prostate
• Pancreas
• Liver
• Cervix

Diagnosis

The cells in a metastatic tumor resemble those in the primary tumor. Once the cancerous tissue is examined under a microscope to determine the cell type, a doctor can usually tell whether that type of cell is normally found in the part of the body from which the tissue sample was taken.

For instance, breast cancer cells look the same whether they are found in the breast or have spread to another part of the body. So, if a tissue sample taken from a tumor in the lung contains cells that look like breast cells, the doctor determines that the lung tumor is a secondary tumor. Still, the determination of the primary tumor can often be very difficult, and the pathologist may have to use several adjuvant techniques, such as immunohistochemistry, FISH (fluorescent in situ hybridization), and others. Despite the use of techniques, in some cases the primary tumor remains unidentified.

Metastatic cancers may be found at the same time as the primary tumor, or months or years later. When a second tumor is found in a patient that has been treated for cancer in the past, it is more often a metastasis than another primary tumor.

It was previously thought that most cancer cells have a low metastatic potential and that there are rare cells that develop the ability to metastasize through the development of somatic mutations. According to this theory, diagnosis of metastatic cancers is only possible after the event of metastasis. Traditional means of diagnosing cancer (e.g. a biopsy) would only investigate a subpopulation of the cancer cells and would very likely not sample from the subpopulation with metastatic potential.

The somatic mutation theory of metastasis development has not been substantiated in human cancers. Rather, it seems that the genetic state of the primary tumor reflects the ability of that cancer to metastasize. Research comparing gene expression between primary and metastatic adenocarcinomas identified a subset of genes whose expression could distinguish primary tumors from metastatic tumors, dubbed a "metastatic signature." Up-regulated genes in the signature include: SNRPF, HNRPAB, DHPS and securin. Actin, myosin and MHC class II down-regulation was also associated with the signature. Additionally, the metastatic-associated expression of these genes was also observed in some primary tumors, indicating that cells with the potential to metastasize could be identified concurrently with diagnosis of the primary tumor.

Expression of this metastatic signature has been correlated with a poor prognosis and has been shown to be consistent in several types of cancer. Prognosis was shown to be worse for individuals whose primary tumors expressed the metastatic signature. Additionally, the expression of these metastatic-associated genes was shown to apply to other cancer types in addition to adenocarcinoma. Metastases of breast cancer, medulloblastoma and prostate cancer all had similar expression patterns of these metastasis-associated genes.

The identification of this metastasis-associated signature provides promise for identifying cells with metastatic potential within the primary tumor and hope for improving the prognosis of these metastatic-associated cancers. Additionally, by identifying the genes whose expression is changed in metastasis offers potential targets to inhibit metastasis.

• Cut surface of a humerus sawn lengthwise, showing a large cancerous metastasis (the whitish tumor between the head and the shaft of the bone)

• Micrograph of thyroid cancer (papillary thyroid carcinoma) in a lymph node of the neck. H&E stain

• CT image of multiple liver metastases

• CT image of a lung metastasis

• Metastasis proven by liver biopsy (tumor (adenocarcinoma) - lower two-thirds of image). H&E stain.

• Metastatic cancer in the lungs

• Metastases from the lungs to the brain

• Metastases from the lungs to the pancreas

Management

Treatment and survival is determined, to a great extent, by whether or not a cancer remains localized or spreads to other locations in the body. If the cancer metastasizes to other tissues or organs it usually dramatically increases a patient's likelihood of death. Some cancers - such as some forms of leukemia, a cancer of the blood, or malignancies in the brain - can kill without spreading at all.

Once a cancer has metastasized it may still be treated with radiosurgery, chemotherapy, radiation therapy, biological therapy, hormone therapy, surgery, or a combination of these interventions ("multimodal therapy"). The choice of treatment depends on a large number of factors, including the type of primary cancer, the size and location of the metastases, the patient's age and general health, and the types of treatments used previously. In patients diagnosed with CUP it is often still possible to treat the disease even when the primary tumor cannot be located.

Current treatments are rarely able to cure metastatic cancer though some tumors, such as testicular cancer and thyroid cancer, are usually still curable.

Research

Although metastasis is widely accepted to be the result of the tumor cells migration, there is a hypothesis saying that some metastases are the result of inflammatory processes by abnormal immune cells. The existence of metastatic cancers in the absence of primary tumors also suggests that metastasis is not always caused by malignant cells that leave primary tumors.

History

In March 2014 researchers discovered the oldest complete example of a human with metastatic cancer. The tumors had developed in a 3,000-year-old skeleton found in 2013 in a tomb in Sudan dating back to 1200 BC. The skeleton was analyzed using radiography and a scanning electron microscope. These findings were published in the Public Library of Science journal.

See also

• Brain metastasis
• Brown–Séquard syndrome (Sections on cavernous malformation, germinoma, renal cell carcinoma and lung cancer)
• Contact normalization
• Disseminated disease
• Mouse models of breast cancer metastasis
• PET (positron emission tomography)

References

External links

Medical information about metastatic cancer

• Q&A: Metastatic Cancer – from the National Cancer Institute
• Invasion and Metastases – from Cancer Medicine e.5
• How Cancer Grows and Spreads – an interactive Flash presentation that explores the progression of a carcinoma from a single cell to metastasis; from Children's Hospital Boston

Charities and advocacy groups dealing with metastatic cancer

• The MetaCancer Foundation – resources and support for metastatic cancer survivors and their caregivers
• Metastatic Breast Cancer Network
• Children's Cancer Research Charity for Metastatic Cancer in Kids

UpToDate Contents

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• 1. 原発不明癌の分類およびマネージメントの概要 overview of the classification and management of cancers of unknown primary site
• 2. 原発不明の腺癌 adenocarcinoma of unknown primary site
• 3. 原発不明の扁平上皮癌 squamous cell carcinoma of unknown primary site
• 4. 播種性転移した去勢感受性前立腺癌の治療法の概要 overview of the treatment of disseminated castration sensitive prostate cancer
• 5. 切除可能大腸癌の肝転移のマネージメント management of potentially resectable colorectal cancer liver metastases

English Journal

• Bisphenol A stimulates human prostate cancer cell migration via remodelling of calcium signalling.

• Derouiche S, Warnier M, Mariot P, Gosset P, Mauroy B, Bonnal JL, Slomianny C, Delcourt P, Prevarskaya N, Roudbaraki M.SourceInserm, U-1003, Equipe labellisée par la Ligue Nationale contre le cancer, Villeneuve d'Ascq, France ; Laboratory of Excellence, Ion Channels Science and Therapeutics; Université Lille I Sciences et Technologies, Villeneuve d'Ascq, France.
• SpringerPlus.Springerplus.2013 Dec;2(1):54. Epub 2013 Feb 15.
• Bisphenol A (BPA), the principal constituent of reusable water bottles, metal cans, and plastic food containers, has been shown to be involved in human prostate cancer (PCa) cell proliferation. The aim of the present study was to explore the effect of BPA on PCa cell migration and the pathways invol
• PMID 23450760

• RNA interference targeting adrenomedullin induces apoptosis and reduces the growth of human bladder urothelial cell carcinoma.

• Liu AG, Zhang XZ, Li FB, Zhao YL, Guo YC, Yang RM.SourceDepartment of Interventional Therapy, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China.
• Medical oncology (Northwood, London, England).Med Oncol.2013 Sep;30(3):616. doi: 10.1007/s12032-013-0616-6. Epub 2013 May 29.
• Adrenomedullin (ADM) is a potent, long-lasting angiogenic peptide that was originally isolated from human pheochromocytoma. ADM signaling is of particular significance in endothelial cell biology because the peptide protects cells from apoptosis, and ADM has been shown to be pro-tumorigenic in that
• PMID 23715749

• Expression of synuclein gamma indicates poor prognosis of triple-negative breast cancer.

• Wu K, Huang S, Zhu M, Lu Y, Chen J, Wang Y, Lin Q, Shen W, Zhang S, Zhu J, Shi YE, Weng Z.SourceDepartment of Surgery, Xinhua Hospital Shanghai Jiaotong University School of Medicine, Shanghai, 200092, China.
• Medical oncology (Northwood, London, England).Med Oncol.2013 Sep;30(3):612. doi: 10.1007/s12032-013-0612-x. Epub 2013 May 22.
• Synuclein gamma (SNCG), previously identified as breast cancer-specific gene 1, is highly expressed in malignant cells but not in normal epithelium. Studies have demonstrated that the expression of SNCG is an independent predictive marker for recurrence and metastasis in breast cancer. Triple-negati
• PMID 23696021

Japanese Journal

• 腋窩リンパ節転移で発見され胸筋温存乳房切除術を施行した潜在性乳癌の2例

• 深光 岳,野島 真治,杉山 望,金田 好和,須藤 隆一郎,亀井 敏昭
• 山口医学 64(2), 153-157, 2015-05-01
• … Breast cancer metastases to the axillary lymph nodes were suspected. … She was diagnosed with latent breast cancer and underwent mastectomy and axillary lymphadenectomy. … Axillary lymph node biopsy revealed invasive ductal breast carcinoma, leading to a diagnosis of latent breast cancer. … Latent breast cancer develops at a low incidence, 0.3-1% of all breast cancers, and therapeutic strategies are determined on an individual basis at each institution. …
• NAID 120005617817

• 卵巣転移によるMeigs症候群を来すも無再発を維持しているS状結腸癌の1例 : 大腸癌卵巣転移によるMeigs症候群本邦報告34例の集計

• 久保 秀文,長岡 知里,多田 耕輔,宮原 誠,長谷川 博康,山下 吉美
• 山口医学 64(2), 129-137, 2015-05-01
• … bevacizumab+XELOX療法による術後化学療法を投与し,術後14ヵ月経過する現在無再発にて生存中である.胸腹水を伴う骨盤腫瘤のある患者ではMeigs症候群も念頭において精査を進めるとともに,消化器系の悪性腫瘍の検索をする必要がある.また本症候群を大腸癌の終末期である癌性胸･腹膜炎と誤診しないことも重要である.We report a rare case of Meigs syndrome caused by ovarian metastases from sigmoid colon cancer. …
• NAID 120005617814

• 胸腔鏡下肺部分切除後にポート孔再発した大腸癌肺転移

• 蓮沼 綾子,塩野 知志,片平 真人 [他]
• 胸部外科 = The Japanese journal of thoracic surgery 68(5), 339-342, 2015-05
• NAID 40020458552

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★リンクテーブル★

リンク元	「がん転移」
関連記事	「metastasis」「cancer」

「がん転移」

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英

cancer metastasis

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癌転移

「metastasis」

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• n.

• 転移

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meta, ガン転移

　 　

「cancer」

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同

癌腫

関

tumor