Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 35

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  przerzuty nowotworowe
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
A malignant tumor predominantly consists of proliferating cells, a smaller percentage of the cells in the resting phase G0 and G1, as well as necrotic and/or apoptotic cells. It is a heterogeneous structure with the ability to metastasize which includes the acquisition of additional genetic mutation, migration ability or the production of MMP (metalloproteinase). Unfortunately, at present it is impossible to find tissue cells with clearly specify features of metastasis in the tumor, and therefore it requires more intense research in this direction. This paper describes the stages of the cancer cell migration from a place of origin, the effect of which is to create metastatic deposits. The metastatic process is compared to the adoption of “seedlings in the soil” (seed and soil). Complementary adhesion molecules are expressed in both the metastatic cells as well as in the target organ cells. The stroma of an organ decides whether cancer cells are adopted. It should be characterized by the absence of proteinase inhibitors, the presence of various growth factors and the ability of neoangiogenesis. Each metastasis can be a point of departure for further metastasis. It has been also describes a number of metastatic mechanisms, i.e. involved in the process of chemokines, adhesion molecules, neoangiogenesis, types of Lewis antigens a, b, x, y, cancer stem cells (CSC), and presents the phenomenon of transmigration through the blood vessels, which is similar to the migration of granulocytes in the system. Tumor cell clones with a high metastatic potential differ from low metastatic counterparts with regard to pheno- and genotypic features. This means that not all of the malignant tumors have the same invasiveness or metastatic potential. Therefore, special attention was paid to the role of genes in metastatic neoplasia (genes: SDF1, BRMS1, MET, IAP-4, KAI-1, KISS-1, NM-23-H1, UGT8, alpha Klotho). The newly discovered intercellular connections are also mentioned, i.e. membrane nanotubes (tunnel – TNTs), enabling the mitochondrial transport between cells, mtDNA transfer and its mutation, as well as mediate in the phenomenon of MDR (multidrug resistance), i.e. removal the xenobiotics from the cells (such as cytostatics), which explains the failure of cancer chemotherapy. Unfortunately recognition of all metastatic molecular mechanisms has not been fully explained to date.
Medycyna Weterynaryjna
|
2010
|
tom 66
|
nr 11
s.745-750,fot.,rys.,bibliogr.
The aim of this article is to summarize current data on the role of growth factors in the development of mammary tumors and their receptor expression as tumor markers. Particular attention is paid to IGF-I and IGF-IR in canine mammary tumors. The growth of a canine and human mammary cancer is regulated not only by sex steroid hormones but also by growth factors (GFs). Growth factors control such critical processes as the growth of the cell, differentiation, angiogenesis and apoptosis in a normal mammary gland. In malignancies these signaling pathways are often exploited to stimulate tumor growth and metastasis. In recent years there has been an increased understanding of aberrations in the insulin-like growth factor-I and its receptor (IGF-I, IGF-IR) responsible for or accompanying human and canine mammary carcinogenesis. IGF-IR demonstrates a tyrosine kinase activity and closely resembles the insulin receptor (IR) in structural as well as in signaling cascades. The binding of the ligands IGF-I or IGF-II to IGF-IR causes the phosphorylation of the IGF-IR tyrosine kinase rest located in the cytoplasmic portion of the β-subunit, then the Ras/ MAPK and PI-3K/Akt pathways associated with cell differentiation are activated and apoptosis is inhibited. IGF-IR is overexpressed in mammary tumor cells and has been implicated in tumor aggressiveness. IGF-IR expression contributes to cancer cell migration as well as cell-cell adhesion. The assessment of IGF-IR expression seems to be a significant indicator of prognosis. There are only a few studies on the role of IGF-I/IGF-IR in canine mammary neoplasms. Interestingly, the cross-talk between estrogens/ERα and IGF-I/IGF-IR has been demonstrated in breast cancer. Most in vitro studies demonstrate that estrogens and IGF-I have a synergistic effect on the proliferation of breast cancer cells. In the case of canine mammary tumors this potential relationship has not been thoroughly investigated, but it has been hypothesized that such a mechanism of cross-talk between sex hormones and the IGF-I pathway might promote carcinogenesis in an autocrine/paracrine manner. A further understanding of this mechanism could lead to the development of new therapeutic strategies in canine and human mammary neoplasms.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.