Genetics of Tumor Suppressor Genes 🧬

Question 1

Tumor Suppressor Genes

Answer 1

Genes that cause cancer when their function is lost. They control cell cycle, promote apoptosis, and repair DNA.

Question 2

Two Hit Hypothesis

Answer 2

Concept where two mutations are needed for tumor initiation. First hit can be inherited, second hit occurs randomly.

Question 3

Epigenetic Changes

Answer 3

Aberrant methylation of genes leading to gene silencing. Can contribute to tumorigenesis.

Question 4

DNA silencing

Answer 4

Mechanisms producing 2nd hit in tumor formation through aberrant methylation.

Question 5

Retinoblastoma

Answer 5

Childhood cancer linked to mutation in Rb gene on chromosome 13, manifests with white pupillary reflex.

Question 6

HNPCC (Lynch syndrome)

Answer 6

Hereditary non-polyposis colon cancer with defects in DNA mismatch repair, characterized by few polyps but rapid progression.

Question 7

BRCA1 and BRCA2

Answer 7

Genes associated with breast cancer susceptibility, involved in DNA repair and apoptosis, mutations can predispose to cancer

Question 8

Apoptosis in Cancer

Answer 8

Process of programmed cell death important for controlling cell proliferation and avoiding cancer development, involves regulatory genes such as p53, BAX, and BCL-2

Question 9

Familial Cancer Syndromes

Answer 9

Inherited predisposition to cancer due to mutations in tumor suppressor genes. Examples include Li-Fraumeni syndrome and hereditary nonpolyposis colon cancer.

Question 10

Rb protein

Answer 10

Regulator of G1/S phase transition, critical for driving G1-S transition during cell division.

Question 11

Li-Fraumeni syndrome

Answer 11

Rare disorder with inherited p53 mutation, associated with increased risk of various cancers.

Question 12

MMR Genes

Answer 12

DNA mismatch repair genes responsible for maintaining genome stability, mutations in these genes lead to increased mutation rates

Question 13

Epigenetics in Tumorigenesis

Answer 13

Altered DNA methylation and histone modifications in tumor cells, silencing of tumor suppressor loci and potential roles in cancer initiation or progression

Question 14

Loss of Heterozygosity

Answer 14

When normal allele is lost and mutant allele is expressed in tumor tissue. A key concept in the Two Hit Hypothesis.

Question 15

p53

Answer 15

Tumor suppressor protein that regulates cell cycle and apoptosis, mutated in over 50% of cancers.

Question 16

Familial Adenomatous Polyposis (FAP)

Answer 16

Inherited disorder with mutations in APC gene leading to numerous adenomatous polyps in the colon.

Question 17

Microsatellite Instability

Answer 17

Phenomenon where tumors exhibit errors in short repetitive sequences of DNA, indicating defects in DNA repair mechanisms

Question 18

MicroRNA in Tumorigenesis

Answer 18

Regulation of gene expression by miRNAs, implicated in oncogene activation and tumor suppressor gene inhibition, aberrant expression of miRNAs can be tumorigenic