2-22_24-11 Cancer Genetics

2-22_24-11 Cancer Genetics - Genetic Analysis II February...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
THE GENETIC BASIS OF CANCER Genetic Analysis II February 22 & 24, 2011 Reading: Chapter on Cancer Genetics , in Human Molecular Genetics , Strachan and Read Chapter 18 in the 2nd edition, or Chapter 17 in the 3rd edition. (2nd edition is available on-line in the NCBI Bookshelf)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
It is a genetic disease at the cellular level. More than 100 kinds of human cancers are known. These are classified according to tissue of origin, i.e., the type of cell that has become cancerous. ~ 1 million Americans are diagnosed with cancer each year; About 500,000 will die from the disease each year. Cancer is a disease characterized by uncontrolled cell division.
Background image of page 2
Most cancers are thought to originate in a single cell. In this regard, a cancer can be considered clonal . At the cellular and genetic levels, cancer is usually a multistep process. It begins with a precancerous genetic change that confirs a cellular growth advantage (i.e., a benign growth). Following additional genetic changes, one or a few clones of cells progress to cancerous growth. Once a cellular growth has become malignant , the cells are invasive (i.e., they can invade surrounding healthy tissue). They are also metastatic (i.e., they can migrate to other parts of the body, and establish secondary tumors there). Some Cancer Characteristics:
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17_02.jpg Tumor cell populations undergo clonal evolution
Background image of page 4
5 - 10% of cancers are familial; They involve an inherited predisposition. 90-95% are “sporadic”, not (apparently) familial; A small subset result from spontaneous mutations and viral infections (e.g., cervical cancer induced by Human Papilloma Virus). However, at least 80% of cancers are thought to arise from exposure to mutagens that alter the structure and (therefore) the expression of genes. An environmental agent that causes cancer is termed a carcinogen . Most carcinogens are mutagens. Cancer Characteristics (cont.):
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The process of converting a normal cell into a malignant cell is termed transformation . A few viruses are known to cause cancer in plants, animals and humans. Many of these viruses can also infect lab-grown cells and transform them into malignant cells. Most cancer-causing viruses are not very potent at inducing cancer. most viruses are also inefficient at transforming normal human cells grown in the lab. Certain Viruses Can Cause Cancer
Background image of page 6
But a few types of viruses can rapidly induce tumors in animals and efficiently transform cells in culture. These are called acutely transforming viruses (ACVs). The first ACV, the Rous sarcoma virus (RSV), was isolated from chickens by Peyton Rous in 1911. During the 1970s, RSV research led to the
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 41

2-22_24-11 Cancer Genetics - Genetic Analysis II February...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online