7 - Neoplasia

Question 1

What is cancer?
What is neoplasia?
What is neoplasm?

Answer 1

It is a disorder of altered cell differentiation and growth.
Tend to be relatively uncoordinated and autonomous, lacking normal regulatory controls over cell growth and division.
The new growth

Question 2

What is cell proliferation?

What is cell differentiation?

Answer 2

The process of cell division, is an inherent adaptive mechanism for cell replacement when old cells die or additional cells are needed.
Is the process of specialization whereby new cells acquire the structural, microscopic, and functional characteristics of the cells they replace.

Question 3

Benign neoplasms are?

Malignant neoplasms are?

Answer 3

Are composed of well-differentiated cells that resemble the normal counterpart both in terms of structure and function but have lost the ability to control cell proliferation. Are usually named by adding a oma to the parenchyma tissue type from which the growth originated.
Are less differentiate and have lost the ability to control both cell differentiation and proliferation. Can also be from evasion of apoptosis. Carcinoma is added to designate a malignant tumour of epithelial tissue origin. Sarcomas are mesenchymal origin.

Question 4

What is apoptosis?

Answer 4

Is a form of programmed cell death that eliminates senescent cells, DNA, and damaged or unwanted cells.

Question 5

The difference between benign and malignant Tumor by 4 characteristics

Answer 5

1. The characteristics of the tumor cells.
2. The rate of growth
3. Local invasion.
4. The ability to metastasize.

Question 6

What are benign neoplasms?

Answer 6

Are composed of well-differentiated cells that resemble the cells of thee tissues of origin and are generally characterized by a slow, progressive rate of growth that may one to a standstill or regress. Have lost the ability to suppress the genetic program for cell proliferation but have retained the program for normal cell differentiation. They grow by expansion and remain localized to their site of origin and do not have the capacity to infiltrate, invade or metastasize to distant sites. Because they expand slowly they develop a surrounding rim of connective tissue called fibrous capsule, leaves a sharp line between the tumor and adjacent tissues so is easily removed surgically.

Question 7

What are malignant neoplasms?

Answer 7

Tend to grow rapidly, invade and infiltrate nearby tissue, and spread to other parts of the body. Lack a well-defined capsule and their margins are not clearly separated from the normal surrounding tissue. Because of rapid growth tumors may compress blood vessels and outgrow their blood supply, causing ischemia and tissue injury. Some secrete hormones and or cytokines, liberate enzymes and toxins and or induce an inflammatory response that injures normal tissue

Question 8

What are the two types of malignant neoplasms?

Answer 8

1. Solid tumors - initially are confined to a specific tissue or organ. As the growth of the primary solid tumor progresses, cells detach from the original tumor mass, invade the surrounding tissue and enter the blood and lymph system to spread to distant sites, metastasis.
2. Hematologic cancers involve cells normally found within the blood and lymph, thereby making them disseminated diseased from the beginning.

Question 9

How do they grade tumors with differentiation and anaplasia?

Answer 9

Is based on the degree of differentiation and the number of proliferating cells. The closer the tumor cells resemble comparable normal tissue cells, both structurally and functionally the lower the grade. Scale ranging from I to IV. I are well differentiated and IV are poorly differentiated and display marked anaplasia.

Question 10

Cancer is studied for growth and behaviour by using culture techniques. What are they?

Answer 10

1. Differentiation and anaplasia.
2. Genetic instability and chromosomal abnormalities - most commonly results in gross chromosomal abnormalities.
3. Growth properties - distinguish cancer cells from normal cells. Include growth factor independence, lack of cell density- dependent inhibition, impaired cohesiveness and adhesion, loss of anchorage dependence, faulty cell to cell communication and an indefinite cell life span or immortality.
4. Functional features - tend to function on a more primitive level than normal cells.they can revert to earlier stages of gene expression and produce antigens that are immunologically distinct from the antigens that are expressed by cells. They can also engage in the abnormal production of substances that affect body function.

Question 11

The rate of growth in normal and cancerous tissue depends on three factors?

Answer 11

1. The number of cells that are actively dividing or moving through the cell cycle.
2. The duration of the cell cycle
3. The number of cells that are being lost relative to the number of new cells being produced.

Question 12

What is invasion?

What is metastatic spread? How do they disseminate?

Answer 12

Invading into surrounding tissues, seeding of cancer cells in body cavities and metastatic spread.
Is used to describe the development of a secondary tumor in a location distant from the primary tumor. They frequently retain many of the microscopic characteristics of the primary tumor.
Two pathways, lymph channels and blood vessels. Lymph is more common in carcinomas, blood by sarcomas.

Question 13

What are the ethology of cancer?

Answer 13

1. The genetic and molecular mechanisms that characterize the transformation of normal cells into cancer cells.
2. The external and more contextual factors such as age, heredity, and environmental agents that contribute to its development and progression.

Question 14

What are the two categories for cancer-associated genes?

Answer 14

1. Gene overactivity - oncogene formation where there is a single nucleotide base change such as activation of the rays oncogene can inc cell proliferation. Another is gene amplification such as epidermal growth factor receptor.
2. Gene underactivity. - normal cells have regulatory genetic mechanisms that protect them against activate or newly acquired oncogenes. Called tumor-suppressor genes these genes tend to behave normally until there is homologous deletion, inactivation, or silencing of both the maternal and paternal genes. Two of the best known are p53 and retinoblastoma genes

Question 15

What is epigenetic mechanisms for etiology of cancer?

Answer 15

They involve changes in the patterns of gene expression without a change in DNA. They may “silence” genes such as the tumor suppressor genes.

Question 16

What are some of the molecular and cellular pathways known or suspected to facilitate the development of cancer?

Answer 16

These mechanisms include defects in DNA repair mechanisms, disorders in growth factor signaling pathways, evasion of apoptosis, development of sustained angiogenesis and evasion of metastasis.

Question 17

What is the three stages by which carcinogenic agents cause normal cells to become cancer cells?

Answer 17

1. Initiation - involves exposure of cells to doses of a carcinogenic agent that induce malignant transformation. Can be chemical, physical, or biological and they produce irreversible change in the genome of a previously normal cell.
2. Promotion - involves the induction of unregulated accelerated growth in already initiated cells by various chemicals and growth factors.
3. Progression - is the process whereby tumor cells acquire malignant phenotypic changes. May promote the cells ability to proliferate autonomously, invade or metastasize and may also destabilize its karyotype

Question 18

What are the four host and environmental factors?

Answer 18

1. Heredity - genetic predisposition for development of cancer
2. Hormones - the link between hormones and cancer is unclear it has been suggested that it may reside with the ability of hormones to drive the cell division of malignant phenotype.
3. Obesity - has been associated with insulin resistance and increased production of pancreatic insulin, both can have a carcinogenic effect. Increased levels of sex hormones - which stimulate cell proliferation, inhibit apoptosis. Has been related to condition of chronic inflammation
4. Immunologic mechanisms - immune system plays a central role in protection against tumors

Question 19

Continued what are the environmental factors three of them?

Answer 19

1. Chemical carcinogens - two groups - direct-reacting agents and indirect -reacting agents. Such as smoking drinking chemicals at work, and chemicals in food
2. Radiation - ionizing radiation (atomic bomb, diagnostically exposed). Higher rates of skiing and leukaemia cancer ultraviolet radiation and skin cancer
3. Viral and microbial agents - such as HPV, EBV, HBV hepatitis, HHV herpes.

Question 20

What are the local/regional and systemic manifestations?

Answer 20

1. Local are primary site involve such as lung cancer causing respiratory issues, abdominal cancer will cause bowel obstruction or press on blood vessels causing ulceration or necrosis or might develop effusions
2. Systemic - anemia, anorexia and cachexia, fatigue and sleep disorders, paraneoplastic syndromes - elaboration of hormones, circulating factors, hormones (Inappropriate ADH secretion, Cushing syndrome and hypercalcemia), production of circulating mediators that cause hematologic complications, symptomatic paraneoplastic neurologic disorders.

Question 21

How do they screen for cancers?

Answer 21

1. Observation
2. Palpating
3. Lab test

Question 22

What are the diagnostic methods for finding cancer?

Answer 22

Tumor markers - are antigens expressed on the surface of tumor cells or substances released from normal cells in response to the presence of tumor. Serum markers are hCG, prostate PSA, CA-125, CD blood cell antigens, and carcinoembryonic antigen CEA. Some express fetal antigens one alpha fetoprotein AFP and CEA. But they can also be elevated in benign conditions
Cytologic, histology, and gene-profiling. PAP smear and tissue biopsy. Immunohistochemistry - can be used to find the site of origin from metastatic. Microarray technology - has the advantage of analyzing a large number of moecular changes in cancer cells to determine overall patterns of behaviour
Staging and grading tumors - grading involves the microscopic examination of cancer cells to determine their level of differentiation and the number of mitosis. Staging uses methods of determine the extent and spread of the disease, uses ct or MRI or surgical exploration, the TNM system - t for primary tumor, n for regional lymph node involvement, m for metastasis.

Question 23

What are the three categories of cancer treatment? The most common treatments are?

Answer 23

curative, control and palliative

1. Surgery - used for diagnosis, staging, tumor removal, and palliation(relief of symptoms).
2. Radiation therapy - can be used as primary method of treatment, as preoperative or postoperative treatment, with chemotherapy or along with chemotherapy and surgery. Can also be used palliative treatment to reduce symptoms. Through ionizing radiation indirect through xrays or gamma rays side effects are infection, bleeding and anemia, nausea and vomiting to gi cells loss. Can be delivered in three ways external beam or teletherapy, with beams generated by a linear accelerator or cobalt -60 matching at a distance, brachytherapy a sealed radioactive source is placed close to or directly in the tumor site and systemic therapy in which radioisotopes with a short half-life are given by mouth or injected into the tumor site.
3. Chemotherapy - is a systemic treatment that enables drugs to reach the site of the tumor as well as distant sites. They are more affective against tumor with a high growth fraction. A major problem is development of cellular resistance so they usually see a better result with combination chemotherapy.
4. Hormone and anti hormone therapy - consists of adminstration of drugs designed to deprive the cancer cells of the hormonal signals
5. Bio therapy - use of immunotherapy and biological response modifiers as a means of changing a person’s immune response - monoclonal antibodies and cytokines and adjuvants
6. Targeted therapy -

Question 24

Chemotherapy side effects are?

Answer 24

As they affect normal cells as well as cancerous cells - there’s acute and intermediate - acute are anorexia, nausea and vomiting and can be relieved by antiemetic drugs. Alopecia is usually temporary May experience changes to menstrual flow and men can see decreased sperm count or absence suppress bone marrow - anemia, neutropenia and thrombocytopenia