Validity of Tests for Carcinogenicity

There is quite a bit of debate among scientists and regulatory agencies about how to assess the carcinogenic hazards of chemicals, both man-made and natural, in our environment. Much of this debate has spilled over into the media, generating a sort of carcinogen-of-the-month club'' and much confusion among the public. Indeed, as one observer put it, ''Cancer news is a health hazard.''93 For many years, the prevailing view among cancer epidemiologists has been that 60 to 90 of human cancers are...

SV40 Virus in Early Polio Vaccines

Polio vaccines have been blamed for everything from initiating the AIDS epidemic to being a Western plot to subvert the developing world. Poliovirus vaccines that were used during the late 1950s and early 1960s were contaminated with simian virus 40 (SV40), a monkey virus that came from the monkey cells in which early batches of the vaccine were grown. A survey done in 1961 indicated that about 90 of U.S. citizens younger than 20 years of age (those born between 1941 and 1961) had received at...

Endogenous Carcinogenesis

An important question that arises is, what is the source of mutations in the human genome that leads to cancer One might argue that the answer is obvious. We live in a sea of carcinogens PAHs from automobile exhaust, industrial pollution, pesticide residues in foods, chlorinated organic compounds in drinking water, etc. Furthermore, epidemiologists argue that almost 30 of human cancers are related to cigarette smoking. Yet, a significant amount of cancers occur in people with no clear evidence...

Basic Facts About Cancer

Cancer is a complex family of diseases, and carcinogenesis, the events that turn a normal cell in the body into a cancer cell, is a complex multistep process. From a clinical point of view, cancer is a large group of diseases, perhaps up to a hundred or more, that vary in their age of onset, rate of growth, state of cellular differentiation, diagnostic detectability, invasiveness, metastatic potential, response to treatment, and prognosis. From a molecular and cell biological point of view,...

Fibroblast Growth Factor

Using initiation of DNA synthesis in mouse 3T3 fibroblasts to monitor purification, Gospodar-owicz246 isolated from bovine pituitary a mito-genic polypeptide, which he called fibroblast growth factor (FGF). Distinct from the IGFs, FGF is a potent mitogen for 3T3 cells and other cultured fibroblasts however, by itself it is only about 30 as potent as whole serum. A combination of FGF and glucocorticoids will replace whole serum as a growth promoter for some cell lines (e.g., 3T3) but not for...

Megmegakaryocytes Function

Abbreviations B, B lymphocytes G, granulocytes E, erythroid cells Eo, eosinophils M, macrophages Mast, mast cells Meg megakaryocytes NK, natural killer cells Stem, stem cells T, T lymphocytes. Abbreviations B, B lymphocytes G, granulocytes E, erythroid cells Eo, eosinophils M, macrophages Mast, mast cells Meg megakaryocytes NK, natural killer cells Stem, stem cells T, T lymphocytes. and M-CSF fosters macrophage colony growth. In addition to stimulating progenitor cell proliferation and cellular...

Biology Of Tumor Metastasis

The ''Classic'' Theory of Tumor Metastasis In humans, the earliest detectable malignant lesions are often referred to as in situ cancers (Fig. 4-33). These are small tumors (usually only a few millimeters in diameter) that are localized in tissues. They are usually detected only if they can be endoscopically or directly visualized, for instance, as in the case of carcinoma in situ of the uterine cervix, urinary bladder, or skin, or by examination of biopsy material, as for ductal carcinoma in...

Cervical Cancer

This is almost two different diseases one in the developing world and a different one in the developed world, although the etiology is similar. For example, in the United States and other developed nations, routine PAP smears and gynecologic examinations detect the majority of cases early and the cure rate is close to 100 for patients with pre-invasive lesions (cervical intraepithelial neoplasia, CIN). The cure rate is 92 for localized carcinomas that are minimally invasive.4 However, it is a...

Avoidability Of Cancer

If, as a number of cancer epidemiologists contend, lifestyle accounts for about 80 of all malignant cancers, then presumably the same proportion of cancers should be avoidable. To be more specific, about 30 of all cancers are thought to be related to smoking, 3 to alcohol consumption, 30 to diet, 7 to sexual and reproductive patterns, and another 5 to occupational hazards and industrial products.50,51 Moreover, about1 are estimated to be related to drugs and medical procedures (primarily...

Description of Cancer

Cancer is a group of diseases of higher multicellular organisms. It is characterized by alterations in the expression of multiple genes, leading to dysregulation of the normal cellular program for cell division and cell differentiation. This results in an imbalance of cell replication and cell death that favors growth of a tumor cell population. The characteristics that delineate a malignant cancer from a benign tumor are the abilities to invade locally, to spread to regional lymph nodes, and...

References

Moolgavkar Multistage carcinogenesis and the incidence of colorectal cancer. Proc Natl Acad Sci USA 99 15095, 2002. 2. P. C. Nowell and D. A. Hungerford A minute chromosome in human chronic granulocytic leukemia. Science 132 1497, 1960. 3. J. D. Rowley A new consistent chromosomal abnormality in chronic myelogenous leukemia identified by quinacrine fluorescence and Giemsa staining. Nature 243 290, 1973. 4. A. G. Knudson Two genetic hits (more or less) to cancer. Nat Rev...

Mucins

Mucins are a type of highly glycosylated glycoproteins that a variety of secretory epithelial cells produce. They are 50 to 80 carbohydrate by weight and function to lubricate and protect duc-tal epithelial cells. They contain O-linked glycans serine- and threonine-linked of various lengths and structures, depending on the tissue type in which they are produced. They are made in a wide variety of tissues, including the gastrointestinal tract, lung, breast, pancreas, and ovary. Tumors arising in...

Macroscopic And Microscopic Features Of Neoplasms

The pathologist can gain valuable insights about the nature of a neoplasm by careful examination of the overall appearance of a surgical specimen. Often, by integrating the clinical findings with macroscopic characteristics of a tumor, a tentative differential diagnosis can be reached. Also, notation of whether the tumor is encapsulated, has extended through tissue borders, or reached to the margins of the excision provides important diagnostic information. The location of the anatomic site of...

Alcohol

Alcohol is thought to interact with smoking in the causation of certain cancers, particularly oral and esophageal cancers. Alcohol appears to be synergistic with tobacco in causing cancers of the mouth, pharynx, larynx, and esophagus, but not that of the lung.64,65 In liver cancer, there is good evidence that alcohol consumption sufficient to cause cirrhosis of the liver increases the incidence of liver cancers, perhaps secondary to the chronic damage to the liver caused by alcohol abuse. Pure...

Hallmarks Of Malignant Diseases

Cancer Rate Death Rate Male

Malignant neoplasms or cancers have several distinguishing features that enable the pathologist or experimental cancer biologist to characterize them as abnormal. The most common Figure 1-3. Annual age-adjusted cancer death rates among males for selected cancer types, United States, 1930 to 2001. Rates are age adjusted to the 2000 U.S. standard population. Because of changes in ICD coding, numerator information has changed over time rates for cancers of the lung and bronchus, colon and rectum,...