Lecture 2 - The Nature of Cancer

Question 1

Differentiate between Normal and Cancerous Tissue (3)

Answer 1

1 - Lack of overall structure (Cancer)
2 - Lack of organization (Cancer)
3 - Lack of distance between cells (Cancer)
[^cells are squished together in a mushy, multinucleated slurry]

Question 2

Differentiate between a benign and malignant tumor

Answer 2

Benign tumor: confined to a particular area

Malignant tumor: has invaded and spread to surrounding tissues, but hasn’t spread to rest of the body [yet].

Question 3

What is epithelial tissue? What is it good for? What does it protect?

Answer 3

80% of cancer deaths are attributed to tumors in epithelial tissues. Epithelial cells are found in sheets that line the walls of cavities and channels within the body. They also cover the outside of the body via the skin. By covering these areas, they help by fighting infection, bacteria, toxins, viruses, etc… They are defenders to the underlying tissues.

Question 4

In what ways can tumors be lethal? Can benign tumors be lethal? How?

Answer 4

Tumors can destroy/alter tissues important to critical life functions (lungs, brain, heart, etc…). Benign tumors can be lethal by location and function. In the brain, they can cause increases in intercranial pressure that can kill the host. Other benign tumors can secrete toxic chemicals or other dangerous organic compounds.

Question 5

What is a carcinoma? Give two examples (2)

Answer 5

Carcinomas are the most common type of cancer. They arise in epithelial tissues. Adenocarcinoma arise in excretory epithelial cells. Squamous cells carcinomas arise in other protective epithelial tissues.

Question 6

What is a sarcoma? Give four examples (4)

Answer 6

Sarcomas are cancers that arise in mesenchymal (mesoderm) cells/tissues. 
Osteosarcoma - bone cancer
Liposarcoma - Adipocyte (fat cell)
Leiomyosarcoma - smooth muscle cancer
Rhabdomyosarcoma: skeletal muscle cancer

Question 7

What are hematopoietic malignancies? What are the two types? (2) What is Leukemia?

Answer 7

Hematopoietic malignancies are found in blood forming tissues which includes the immune system.
Chronic: older blood cells, more variated, decreased rates of proliferation
Acute: younger blood cells, less variated, increased rates of proliferation

Leukemia is when the body is full of WBCs [White Blood Cell] that are ineffective/altered and cannot fight infection. They end up choking out the host’s vascular and immune functions.

Question 8

What are neuroectodermal malignancies? Give three tissues they infect. What is the classic example we studied?

Answer 8

Neuroectodermal malignancies are cancers that arise from the CNS and PNS [Central Nervous System, Peripheral Nervous System, respectively].
-Astrocytes
-Ganglia
-Neurons
Classic Example: Retinoblastoma [cone cells in retina]

Question 9

What are melanomas? Where are they found?

Answer 9

Melanomas are cancers that arise from melanocytes [bottom skin cell layer]. Found in skin, eyes, and have a neural crest origin.

Question 10

What are teratomas?

Answer 10

Teratomas are cancers that arise from germ cell precursors that fail to migrate properly during embryonic development. These are typically pleuripotent and form the wrong tissues in the wrong places - monsters.

Question 11

What is transdifferentiation? Give 2 examples.

Answer 11

Transdifferentiation is the switching of tissue lineages and the acquisition of new cancer cell characterisitics. ***Nearly all cancer cells retains some of the distinctive attributes from their precursor cells.
Ex: 1 - epithelial to mesenchymal transition [EMT]
Ex: 2 - small lung cell carcinoma [SCLCs]

Question 12

What are anaplastic tumors? What is CUP

Answer 12

Anaplastic tumors are dedifferentiated, which means the cells have an unknown origin. CUP stands for “Cancer of Unknown Primary Origin”.

Question 13

What are hyperplastic growths? Give a common tissue location example.

Answer 13

Hyperplastic growths are when cancer cells look exactly like normal cells, except for the fact that there are wayyyyyyyy too many of them (far too numerous).
Ex: mammary glands

Question 14

What is metaplasia? Where is this usually found?

Answer 14

Metaplasia is when a normal cell layer is displaced by a mis-localized cell type. This is usually found in epithelial transition zones.

Question 15

What does dysplastic mean? Give some key indicators that cells have become dysplastic. (4) What is this considered to be [state]?

Answer 15

Dysplastic means that cells no longer look cytologically correct [kinda starting to look funny].

• variation in nuclear size, shape [bulbous]
• increase in nuclear staining affinity
• increase in rate of mitotic activity [proliferation]
• not specializing properly

This is considered to be a transitional state or “Pre-Malignant”….. not good news :(

Question 16

What are adenomatous growths? Give two examples. (2)

Answer 16

Adenomatous growths are dysplastic epithelial cells that form large growths but DO NOT invade surrounding tissues.

• Polyps
• Papillomas

Question 17

What does neoplastic mean?

Answer 17

Neoplastic cells are able to breach basement tissues and invade nearby surrounding stroma [extracellular fluid].

Question 18

Cancer develops progressively. Give the order, IN ORDER

5/6 trick step procedure

Answer 18

1 - Normal cell
2 - Hyperplastic/Metaplastic
3 - Dysplastic
4 - Neoplastic
5 - Metastatic

Question 19

Are tumors monoclonal or polyclonal? Explain using an example.

Answer 19

Tumors/cancers are monoclonal, which means that one single mutated cell is the ancestor to all subsequent cells in the tumor.