Chapter 16 Cancer biology & ch16 pt2

What is a complex genetic disease in which changes in DNA results in uncontrolled cell division, causing tumor development

Cancer

Cancer alters DNA in what cells

somatic

Is cancer inherited

No

not cancer

Benign tumors

cancer

Malignant tumors

rarely life-threatening

Benign tumors

may be life-threatening

Malignant tumors

can be removed, and usually do not grow back

Benign tumors

can be removed, but sometimes they grow back

Malignant tumors

do not invade the tissues around them or spread to other parts of the body

Benign tumors

can invade and damage nearby tissues and organs

Malignant tumors

spread of cancer

metastasis

Cancer cells spread by breaking away from the original primary tumor and entering the what or lymphatic system. The cells can invade other organs, forming new tumors that damage these organs.

bloodstream

cancer that begins in the skin or in epithelial tissues that line or cover internal organs

Carcinoma

cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue

Sarcoma

cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood

Leukemia

cancers that begin in the cells of the immune system

Lymphoma and myeloma

cancers that begin in the tissues of the brain and spinal cord

Central nervous system cancers

Gene expression in cancer cells is altered

genetic disorders

Cancer cells proliferate in an uncontrolled manner, forming what tumors

malignant

Malignant tumors tend to
metastasize (establish what tumors)

secondary

Cancer cells ignore inhibitory growth signals, and grow in the what of stimulatory growth signals required by normal cells

absence

Cancer cell growth uninhibited by
– Contact with other what

cells

Cancer cell growth uninhibited by
– Growth factor what

signals

what in cancer cells attributes to tumor growth

Telomerase

Absence of telomerase in normal somatic cells: major defense against what growth

tumor

Diet and environment cannot or can influence risk of developing cancer

can

Diet and environment can influence risk of developing cancer: alter the genome – favoring cell cycle progression and no what

apoptosis

occurs by a cumulative progression of genetic alterations

Tumorigenesis

A cancer what cell can self-replicate and produce progenitors that generate all of the cell types that make up a tumor

stem

In Tumorigenesis Cells become more or less responsive to growth regulation and more invasive

less

The proposed cells of origin of malignant tumors: tumors can arise from either tissue stem cells or what cells

progenitor

Cancer occurs in a what-step process

multi

Usually how many mutations are needed to develop a cancer

multiple

a preparation of homologous pairs ordered according to size

karyotype

The pattern on a karyotype may be used to screen chromosomal what

abnormalities

Cancer cells are also often what

aneuploid

Cancer cells are also often aneuploid
• but- this may or may not be causative
• and this occurs what

somatically

Encode proteins that restrain cell growth

Tumor-suppressor genes

Tumor-suppressor genes:
– Both cellular gene copies must be what

altered

Encode proteins that promote loss of growth control

Oncogenes

Oncogenes are altered cellular genes (proto-oncogenes) that act what

dominantly

Series of events through which loss of two copies of a tumor suppressor gene gives rise to loss of cellular what control

growth

Mutant is non-functional

Recessive

Mutant is more function/always On

Dominant

Tumor-Suppressor Genes: acts as a repressor to regulate the G1 to S transition via E2F transcription factors

Retinoblastoma (RB) mutation: retinoblastoma

Tumor-Suppressor Genes: responsible for about 3% of breast cancers (about 7,500 women per year) and 10% of ovarian cancers (about 2,000 women per year)

BRCA (BReast CAncer gene) 1 and 2 mutation

was the first tumor-suppressor gene to be discovered

Retinoblastoma (RB)

Children with a high risk for RB have how many copies of the mutated RB gen

one

The RB protein (pRB) acts as a what to regulate G1 to S transition via transcription factors of E2F family

repressor

familial

sporadic

The breast cancer susceptibility genes BRCA1 and 2, important for what repair

DNA

BRCA act through the what factor P53 important for DNA repair and cell cycle

transcription

BRCA mutations does what to the risk for breast cancer

increase

?% of the breast cancer cases show defects in brca1 or 2

5-10

breast cancer affects 1/? women (US)

8

a tumor suppressor gene, produces the p53 protein, often called the "guardian of the genome

TP53 gene

TP53 is the most commonly mutated what in human cancers

gene

Lacking TP53 causes inherited disorder called what syndrome, disease with high cancer incidence

Li-Fraumeni

Tumors with TP53 mutations have what prognosis than wild-type TP53 gene

poorer

Loss of TP53 function critical in progression toward which cancer

malignant

p53 is a what factor

transcription

p53 is activated by what double stranded breaks

DNA

p53 turns on what (cdk inhibitor), that inhibits the G1-S transition

p21