Malignant neoplastic cells

Chemotherapy The act of NO release through apoptotic, genotoxic, or other cell death pathways can be harnessed selectively toward malignant neoplastic cells or tissues in chemotherapy, or used to enhance chemo/radiotherapy, or to attenuate resistance to such therapy. 

B and T cells can undergo neoplastic transformation that is governed by specific mutations in their chromosomes that result in populations of malignant lymphoma cells. 

In terms of pharmacokinetics, many host factors, such as the route of administration, the metabolism, the catabolism and clearance will considerably determine the anti neoplastic success of a drug. One major difficulty with the clinical effectiveness of chemotherapy of neoplastic diseases is the requirement that it kill malignant tumor cells at doses that allow cells in the patient s vital organs to survive so that the recovery can occur. In other words, it is to obtain a reasonably safe therapeutic index favoring introduction into clinical practice. 

Blood vessels penetrating tumors provide malignant cells with another point at which to enter the circulation. Evidence exists that in situation where cancers disseminate predominantly by the blood, the extent of metastasis depends upon the vasculature of the primary tumor. Thin-walled capillaries, especially those newly formed, provide poor resistance to invading cancer cells. Also, data from microscopy studies show that the endothelium of tumor vessels, particularly in areas of poor oxygenation, is often abnormal (Kl). These abnormalities may permit invasion by neoplastic cells (P3). Finally, tumors can spread by direct extension into body cavities such as pleural and peritoneal spaces. An example of this is the formation of peritoneal metastases from ovarian carcinoma. 

The division between benign and malignant is useful but too simple. To be a little more precise, we can add the classification of dysplastic tissue. Dysplastic cells are not yet fully malignant but are on their way to getting there. Finally, the term neoplastic is frequently used to describe malignant cells or tumors. So we have the sequence normal, benign, dysplastic, malignant (neoplastic). 

We hypothesize that different patterns of nuclear p-catenin occur, depending on the localization of neoplastic cells in the tumor and correlating with variations in the differentiation state of malignant hepatocyte subpopulations. At the inner area of the cancerous tissue, neoplastic hepatocytes might have low or are even devoid of nuclear p-catenin and exhibit proliferation. In contrast, malignant hepatocytes that have undergone EMT at the invasive front might... 

Butyrate appears to have its most profound effects on neoplastic cells such as HeLa in addition to morphological and biochemical differentiation, the fatty acid inhibits cell growth (2). Previous studies have established a correlation between decreased ganglioside synthesis and malignant transformation (43-46). Transformed baby hamster kidney and newborn rat kidney cells exhibited a loss of GM3 and sialyl transferase activity (43,44). 

Plasma contains protease inhibitors that rapidly inactivate the coagulation proteins as they escape from the site of vessel injury. The most important proteins of this system are -anti protease, 2-macroglobulin, -antiplasmin, and antithrombin. If this system is overwhelmed, generalized intravascular clotting may occur. This process is called disseminated intravascular coagulation (DIC) and may follow massive tissue injury, cell lysis in malignant neoplastic disease, obstetric emergencies such as abruptio placentae, or bacterial sepsis. 

Tumors. Neoplastic cells display a number of biochemical changes compared with normal cells. For example, a number of invasive tumors have been shown to secrete collagenase. This enzyme gives the malignant cells the ability to invade adjacent tissues and to spread as the collagenase dissolves connective tissue collagen. 

FIGURE 12.14 In this malignant epithelioid hemangioendothelioma, the neoplastic cells have an epithelial appearance and can be confused with carcinomas. X 400. 

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