This chapter draws on what you have learned about cell

structure (3.2) and the cell cycle (18.2).

Our discussion here also relates to what you have read about

gene mutations and how cells repair damaged DNA (21.2).

You will read about links between cancer and operations of

the immune system (Chapter 9) and how ionizing radiation

damages DNA (18.5).

Key ConCepts

LinKs to earLier ConCepts

Cancer: Uncontrolled Cell

Division

Cancer cells are abnormal in both

structure and function. Cancer

develops when gene changes

remove the normal controls over cell

division. Sections 22.1 –22.4

Diagnosis and Screening

Cancer is diagnosed by biopsy

and other tools. Early detection

increases the chances of successful

treatment. Section 22.5

Treatment and Prevention

Cancer treatments include surgery,

chemotherapy, radiation, and immuno-

therapy. Lifestyle decisions that pro-

mote health can limit a person’s risk of

developing cancer. Section 22.6

Top: James Stevenson/Science Source; Middle: Will & Deni McIntyre/Science

Source; Bottom: © Blue Planet Earth/Shutterstock.com

Cancer strikes one in three people in the United States

and kills one in four. Henrietta Lacks, shown in the old photograph

below, died of cervical cancer not long after the photograph was

taken. Scientists at Johns Hopkins Hospital removed samples of her

cancerous cells for study. Today, descendants of those “HeLa” cells

are still dividing and being used in research all over the world. In

2010, her cancer struggle and her unknowing contribution to cancer

research became the subject of a best-selling book.

Intensive research is rapidly increasing our understanding of the

causes of many kinds of cancer. As you’ll read in this chapter, today

most cancers are treatable, and many are curable if the disease is

caught early.

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Genes and disease: CanCer

22

Science Source

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