Chapter 6 Answers to Select Review Questions

1.  Alterations in what three processes drive the initiation of cancer?

The origins of cancer depend upon alterations in one or more of three properties:  regulatory control of the cell cycle; cellular senescence; and/or apoptosis, or programmed cell death.

4.  What hypothesis and theory did Rudolph Virchow formulate regarding the origins of cells and cancer?

Virchow developed the hypothesis of embryonal rest, which highlighted the striking similarity between cancer cells and cells encompassing an early-stage developing embryo and coined the now infamous quote "Omnis cellula e cellula" (All cells come from cells).  This quote is now widely recognized as cell theory.

7.  What is Stewart Sell's hypothesis on the origin of many cancers?

Stewart Sell hypothesized that many cancers originate from the arrest of tissue stem cell maturation.

13.  List and describe the three main properties of cancer stem cells.

Ability to Self-Renew

Self-renewal is perhaps the most critical prerequisite for a CSC to have tumorigenic capability.  It is most often measured via serial tumor transplantation in vivo or through the application of soft agar sphere formation in vitro.

Strong Tumorigenic Potential

            Tumorigenic potential is measured as the number of cells required for tumor induction. 

Establishment of Tumor Heterogeneity

            In order to truly be classified as a cancer stem cell the cell must not only be able to self- replicate and result in the formation of tumors but must also have the capacity to        completely recapitulate the phenotype of the original tumor from which it was isolated.

19.  What markers do pancreatic cancer stem cells express that define them as such?

CD44+, CD24+, ESA+

22.  Why did Richard Jones and colleagues focus on syndecan-1 (CD138) in their search for multiple myeloma cancer-initiating cells?

Richard Jones and his team focused on syndecan-1 because it is a well-known transmembrane domain protein and plasma cell marker that has also been detected in cells representing various tumor types.