Tumour Suppressor Genes and Oncogenes

Question 1

What is oncogenes?

Answer 1

Endogenous human DNA sequences that arise from proto-oncogenes

(Proto-oncogenes are normal genes)

Question 2

What is proto-oncogene?

Answer 2

Normally expressed in many cells >> particularly during foetal development

Plays important regulatory role in cell growth and development

Question 3

Alternations in the proto-oncogene can result-?

Answer 3

Can activate an oncogene >>> that oncogene produces unregulated gene activity >>> tumourogenesis

Question 4

What is the normal function of tumour supressor genes?

Answer 4

controll cell cycle

Question 5

Role of tumour supressor genes?

Answer 5

• Normally down regulate cell gorwth
• required to inactivate them to allow malignant growth

Question 6

How many copies need to be mutated of tumour supressor genes to result the cancer?

Answer 6

2 copies

Exhibit a recessive effect

Caution: many disorders by its mutation: neurofibroma, colorectal carcinoma, Li-fraumeni syndrome

Question 7

Name 7 common tumour supressor genes

Answer 7

P53

RB

NF-1

APC

BRCA 1 & 2

WT1

MTS-1, p16

Question 8

Name 5 common oncogenes

Answer 8

c-myc

BCR-ABL

Her-2/neu (Erb)

ras

N-myc (proto-oncogene)

Question 9

Location of P53 gene

Answer 9

Chromosome 17p13.1

Question 10

What is the most common mutated tumour supressor gene in breast, colon, lung cancer?

Answer 10

P53

Question 11

Role of P53 gene

Answer 11

1. Prevents entry into S-phase of cell cycle until DNA is checked & repaired

2. Key regulator of apoptosis

Question 12

Cancers related to mutation of P53 gene

Answer 12

Breast cancer

Colon cancer

Lung cancer

Common to many cancers as Li-Fraumeni syndrome

Question 13

Result of mutation in APC gene

Answer 13

Colorectal cancer

Question 14

Result of mutation in NF1 gene

Answer 14

Neurofibromatosis

Question 15

Result of mutation in RB gene

Answer 15

Retinoblastoma

Question 16

What is Li-fraumeni syndrome?

Answer 16

Esrly onset of variety of cancers, such as sarcoma, breast cancer etc.

Question 17

c-myc ongene encodes for

Answer 17

transcription factor

Question 18

c-myc oncogene related cancers

Answer 18

Burkitt’s lymphoma

Breast cancer

Ovarian carcinoma

Question 19

BCR-ABL encodes for

Answer 19

Signalling Tyrosine kinase

Question 20

BCR-ABL related cancer

Answer 20

CML

Question 21

Her2/neu (erb) encodes for

Answer 21

Receptor tyrosine kinase

Question 22

Her2/neu (erb) related cancer

Answer 22

Breast carcinoma

Neuroblastoma

Question 23

Result of mutation in BRCA 1 & BRCA2

Answer 23

Breast cancer & Ovarian cancer

Question 24

Result of mutation in WT1

Answer 24

Wilm’s tumour

Question 25

Result of mutation in MTS-1, p16 (Multiple tumour supressore 1)

Answer 25

Melanoma

Question 26

ras oncogene encodes for

Answer 26

Rhabdomyosarcoma

Question 27

N-myc proto-oncogene encodes for-?

Answer 27

Neuroblastoma

(Not all neuroblastoma has poor prognosis)

Question 28

Prognosis of N-myc proto-oncogene in neuroblastoma

Answer 28

Poor prognosis

Question 29

Translocation of c-myc oncogene in Burkitt’s lymphoma

Answer 29

C-myc is translocated intact from its normal position on chromosome 8 to chromosome 14