module 3 patho

Question 1

describe the steps of metastasis

Answer 1

1. must have characteristics to be metastasis
2. initially invade the interstitial spaces of local tissue
3. if carried by lymphatic drainage, go to primary or sentinel lymph nodes
4. enter the venous system as lymph, drains into left and right subclavian veins
5. must evade the innate immune system, one way to do this is to be coated with platelets, thereby appearing as a normal cell
6. secrete proteolytic enzymes in order to penetrate tissues from blood vessels
7. once seeded, the cells must release cytokines and growth factors that control evading tissue functions: to stimulate growth and proliferation & if it grows larger the 1mm, requires own blood supply and perform angiogenesis

Question 2

name and describe the 2 types of growth controlling genes that when altered, may cause cancer (include examples)

Answer 2

a. Proto-oncogenes: normal non-mutant genes that code for proteins that cause the cells to divide. If these do mutate and become more active, thus causing more rapid growth of cells, they are called oncogenes. Example: RAS proteins
b. Tumour suppressor genes: a gene that regulates a cell during cell division and replication. If the cell grows uncontrollably, it will result in cancer. When a tumour suppressor gene is mutated, it results in a loss or reduction in its function. [slow cell growth due to the Recessive Effect with a greater chance of losing both cells since you only have one] (BRCA1 gene in breast cancer)

Question 3

Describe the use of tumour markers

Answer 3

Tumour markers are antigens expressed on the surface of tumour cells or substances released from normal cells in response to the presence of tumours. Can help identify high-risk people, diagnose the tumour and follow a successful treatment

Question 4

describe pap tests

Answer 4

Pap test: the secretions around a tumour can contain cells of the tumour because they shed easily. Examination of the secretion can reveal abnormal cells

Question 5

describe biopsy

Answer 5

Biopsy: removal and examination of tissue sample, (through a needle, an endoscope or surgery)

Question 6

describe immunohistochemistry

Answer 6

Immunohistochemistry: use of antibodies specific for a particular cell product or surface marker to detect the presence of that product or marker.

Question 7

Differentiate between the grading and staging classifications of cancer.

Answer 7

grading: according to cellular characteristics
staging: includes size and spread of the disease

Question 8

staging steps

Answer 8

Stage 1: confined to origin
Stage 2: local invasive
Stage 3: spread to local lymph nodes
Stage 4: spread to distant sites

Question 9

Describe the basis of grading a tumour

Answer 9

a portion of the tumour is obtained through a biopsy. The closer the tumour cells resemble normal tissue, the lower the grade

Question 10

How does the type of cancer usually found in children differ in origin from that of adults?

Answer 10

In adults usually epithelial origin – breast, lungs, colon

Children are not of epithelial origin – brain, leukemia

Question 11

When are childhood cancers usually diagnosed?

Answer 11

Usually during peak times of physical growth and maturation (first years of life and puberty/adolescence) and are generally fast-growing

Question 12

Why can childhood cancers be difficult to diagnose early?

Answer 12

Signs and symptoms are very similar to common childhood diseases.

Question 13

What is the most widely used treatment for childhood cancers? Why?

Answer 13

Chemotherapy because children better tolerate side effects and the type of tumours respond better