Cancer

Question 1

Cancer definition

Answer 1

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph system

Question 2

function of multicellular cells

Answer 2

It is to support the survival of the organism and the propagation of germ cells, which create more of the same organism

Question 3

what dedifferentiates the cell

Answer 3

Mutations that lead to the conferring of a selective advantage of a cell over its neighbors, particularly with respect to increased growth and survivak, can impart a dedfifferentiated or selfish phenotype

Question 4

Micro evolution of cancer

Answer 4

Initial mutations can be followed by successive rounds of mutations that lead to a micro-evolutionary process whereby an abnormal cell’s progeny rapidly undergoes natural selection through competition
this results in development of abnormal cells at expense of neighbors

Question 5

Properties of cancer

Answer 5

-They exhibit uncontrolled proliferation
-They invade areas of the organism reserved for other cells

Question 6

Benign cells

Answer 6

Cells that divide uncontrollably but do not become invasive

Question 7

Malignant

Answer 7

Dividing cells with the ability to invade surrounding tissue and migrate to distal sites within the organism where they form secondary tumors or neoplasms

Question 8

Metastais

Answer 8

Process of spread and invasion that results in death

Question 9

Carcinomas

Answer 9

Epithelial cells (80% of all cancers)

Question 10

Sarcomas

Answer 10

Connective tissue and muscle

Question 11

Lukaemia and lymphoma

Answer 11

Blood cells and precursors

Question 12

How to classify cancer cells

Answer 12

Have characterisitics that reflect their origin:
Melanoma makes melanin, hepatocarcinoma makes albumin

Question 13

Molecular evidence that cancer originates from one cell

Answer 13

Philadelphia chromosome
X-Inactivation patterns

Question 14

Philadelphia chromosome

Answer 14

-It causes chronic myelogenous leukemia
-Translocations of chromosome 22 to 9 results in truncated chromosome 22 ( Philadelphia chromosome)
-It also creates elongated chromosome 9
-This resutls in fusion oncoprotein BCR-ABL1
-ABL1 gene encodes for non-receptor tyrosine kinase
-This causes cell growth, survival, inhibition of apoptosis and activation of transcription factors
-results in constituitively expressed defective Abl

Question 15

X-inactivation

Question 16

Test for precancerous cells

Answer 16

Pap smear

Question 17

Normal epigenetic function

Answer 17

-In normal cells: CpG island promoters are unmethylated and when active, as with tumor suppressor genes, are accompanied by histone marks such as acetylation and H3K4 methylation allowing transcription to occur on open chromatin structure

Question 18

Epigenetic dysregulation

Answer 18

CpG islands for tumor suppressor gene promoters become methylated which forms silent chromain structure

Question 19

Natural selection role in cancer

Answer 19

It favors proliferation and survival over genetic stability

Question 20

Cell cycle and cancer

Answer 20

-Cells have checkpoints that halt cycle if DNA damage is detected and induce apoptosis if DNA repair is not possible
-Cancer cells aquire mutations to inactivate this process

Question 21

Telomeres and cancer

Answer 21

-Cancer cells also escape the built in limit to cell proliferation that normal cells have via telomere shortening
-They express telomerase which repiars and elongates shortened telomeres

Question 22

Tasks for metastasis

Answer 22

-the cell must break free from the ‘mother’ tumor and surrounding tissue that constrains movement; it must become invasive. This reuquires mechanisms to disrupt ECM and tissues
-The cell must travel to distal sites in the organism and survive, proliferate in new tissue environments. This requires entering the blood stream or lymphatic system trhough vessels and exit elsewhere

Question 23

Enzyme that disrupts tissues and ECM

Answer 23

proteases

Question 24

Micrometastasis

Answer 24

Formation of micro colonies or tumors at a new site

Question 25

Angiogenesis

Answer 25

Bllod vessel formation

Question 26

Angiogenesis formation

Answer 26

-Hypoxic conditions stimulate altered gene expression
-Transcriptions factors such as HIF1a are activated
-This results in expression of pro-angigenesis factors such as vascular endothelial growth factor (VEGF) which results in blood vessel formation

Question 27

HIF1a

Answer 27

Hypoxic inducible factor

Question 28

VEGF

Answer 28

Vascular endothelial growth factor

Question 29

Metabolism of cancer

Answer 29

They switch from aerobic to anaerobic metabolism (glycolysis)

Question 30

Tumor micro environment

Answer 30

Consists of fibroblasts, immune cells such as macrophages and endothelial (vascular) cells
-Tumor cells produce factors that recruit and modify stromal and immune cell behaviour to alter ECM of tumor environment