Rush University - NSG 533 Module 5 Oncogenesis Objectives Study Guide. Latest 2021.Student Objectives
On completion of the learning activities, the
... [Show More] student will be able to:
Compare characteristics of malignant and benign tumors.
Benign tumors: retain some normal tissue structure, do not invade or spread, and
include suffix “oma.” Examples: lipoma or organ hypertrophy. They can be life
threatening if enlarge in critical locations
Grow slowly
Have a well defined capsule
Are not invasive
Are well differentiated; look like the tissue from which they arose
Have a low mitotic index; dividing cells are rare
Do not metastasize
Malignant tumors: possess several unique characteristics and ultimately can
metastasize (spread) and result in death due to growing in other organs, tissues, and
structures
Grow rapidly
Are not encapsulated
Invade local structures and tissues
Are poorly differentiated; may not be able to determine tissue of origin
High mitotic index; many dividing cells
Can spread distantly, often through blood vessels and lymphatics
Differentiate between tumors of epithelial origin and those of mesenchymal origin.
Cancer arising from epithelial tissue comprise most of the solid tumor cancers and
are carcinomas
Cancer in situ means that it is in its early stage of growth and is localized to
the epithelium and has not invaded elsewhere
Cancer arising from mesenchymal origin include cancers of the bone marrow,
lymphatic, nerves, and muscles/tendons/connective tissue
Bone marrow and lymphatics: leukemia, lymphoma, multiple myeloma
Nerves: blastomas
Musculoskeletal/tendons/connective tissue: osteosarcoma
Discuss and give examples of tumor markers (see text).
Tumor markers are substances produced by both benign and malignant cells that
either are present in or on tumor cells or are found in blood, spinal fluid, or urine
Tumor markers include hormones, enzymes, genes, antigens, and antibodies
Tumor markers can be used in 3 ways:
To screen and identify individuals at risk for cancer
To help diagnose the specific type of tumor in individuals with clinical
manifestations relating to their tumor (as in adrenal tumors or enlarged
liver/prostate)
To follow the clinical course of a tumor
Example of tumor markers:
Alpha fetoprotein (AFP) type of cancer: hepatic, germ cell
Carcinoembryonic antigen (CEA) type of cancer: GI, pancreas, lung, breast,
etc.
B-Human chorionic gonadotropin (B-hCG) type of cancer: germ cell
Prostate-specific antigen (PSA) type of cancer: prostate
Catecholamines type of cancer: pheochromocytome (adrenal medulla)
Homovanillic acid/vanillylmandelic acid (HVA/VMA) type of cancer:
neuroblastoma
Urinary bence jones protein type of cancer: multiple myeloma
Adrenocorticotropic hormone (ACTH) type of cancer: pituitary adenomas
Discuss major causative factors and significant epidemiological risk factors for the
development of cancer.
Major causative factors
The most important environmental risk factor for cancer is exposure to
cigarette smoking
The process of carcinogenesis usually begins with an irreversible change in
the cell DNA
Significant epidemiological risk factors:
Tobacco
Alcohol
Lack of fruit and vegetables
Meat
Lack of fiber
Overweight
Lack of physical exercise
Post menopause
Infections
Ionizing radiation
Occupational hazard
Reproduction
Sun exposure & sunbeds
Describe the defining characteristics of cancer (dysregulated growth, invasion, metastasis).
Dysregulated growth:
Unrestricted, immortal growth
A tumor is an abnormal growth resulting from uncontrolled proliferation and
serves no physiologic function
Invasion:
Local spread, is a prerequisite for metastasis
Local invasion may occur by direct tumor extension
Mechanisms important in local invasion include recruitment of macrophages
& other cell types to the primary tumor, where they promote digestion of
connective tissue capsules & other structural barriers by secreted proteases
Metastasis:
Metastasis is the spread of cancer cells from the site of the original tumor to
distant tissues & organs through the body
Metastasis is a defining characteristic of cancer, contributes significantly to
the pain & suffering from cancer, & is the major cause of death from cancer
The metastatic spread of tumor cells is facilitated by enzyme secretion that
enables invasion and movement to distant tissues. [Show Less]