Cancer Study Guide Flashcards
(26 cards)
Tumor masses can be either
Benign or Malignant
What are carcinomas and sarcomas?
Carcinomas: Tumor from epithelial origin
Sarcomas: Tumor from mesenchymal origin
Most frequent cancers in the United States:
Lung, colon, breast, prostate. The most lethal form is lung cancer
Cancer is caused by….
multiple mutations developed over the years
What is tumor clonality?
cells in one tumor have the same mutation, example, x chromosome inactivation
Stages of Tumor Development
Tumor initiation: genetic alteration leads to abnormal proliferation of a single cell
Clonal selection: Additional mutations confer a selective advantage of the cell
Clonal selection continues
Tumors become more rapid growing and malignant
Property of cancer cells different from normal cell:
Density-dependent inhibition of proliferation
Contact inhibition of migration; Growth factor requirements, Cell adhesion
How environmental agents lead to cancer?
Such as UV can cause mutations
What is protooncogen, oncogene, tumor suppressor gene
Oncogene is a mutated version of proto oncogene in a normal cell
Oncogenes are first revealed by studies of chicken retrovirus, which usually can pick up oncogenes from host cell
Raf proto-oncogene is converted to a oncogene when its regulatory domain is replaced by a viral domain and it cannot be turned off.
viral domain and it cannot be turned off.
Active from of ras is
the most common oncogene in human tumors
First direct evidence of oncogene in human tumor
DNA extracted from a human bladder carcinoma was able to transform recipient mouse cells in culture
How c-myc becomes an oncogene in Malignancy of B lymphocytes
a translocation to IgH
Proto-oncogenes can be altered in many ways to develop into oncogenes
Mutation in Coding Sequence - hyperactive protein made in normal amounts
Gene Amplification - Normal protein greatly overproduced
Chromosome Rearrangement - Nearby regulatory DNA sequence causes protein to be overproduced OR fusion to actively transcribed gene greatly overproduces fusion protein; or fusion protein is hyperactive
Chronic myelogenous leukemia (CML) is caused by
translocation that results BCR/ABL fusion
Tl/PDGFR is caused by
gene translocation and produce a fusion product that has overactive uncontrolled protein kinase activity
Loss of Function of tumor suppressor can be…
oncogenic
Rb tumor suppressor and its function
Rb is the first tumor suppressor gene identified in Retinoblastoma
BRCA, PTEN, P53 are examples of what?
Tumor Suppressor genes
Loss of two copies of Tumor suppressor gene can lead to…
Cancer, but heterozygous mutations can not
Mutations in BRCA gene leads to
breast cancer and ovarian cancer
P53 two function:
(1) p53 activate p21 to stop cell cycle and repair DNA damage
(2) when severe damage is detected, cell apoptosis.
cancers develop by an accumulation of mutations in multiple genes, why?
This is because a cancer cell must acquire a whole range of abnormal properties to be successful
Standard chemotherapy kills what kind of cells?
Cells undergoing cell division
