Chapter 22, Problem 1RQ

Summary Introduction

To determine: The way by which cancer cells are structurally different from normal cells of the same tissue.

Introduction: Cancer is caused due to abnormal cell growth. This occurs due to several genetic and epigenetic alterations that cause uncontrolled proliferation of cells. The word tumor is used to refer swelling, but now it is used to describe the new growth or neoplasm (cancerous growth). The clinical manifestations of cancer are numerous and depend on the variety and intensity of symptoms.

Explanation of Solution

The structural difference between the normal cells and cancer cells are as follows:

Characteristics	Normal cells	Cancer cells
Shape of cells	Normal and regular cell	Irregular
Nucleus	Proportionate size	Enlarged and darker nuclei
Cytoplasm	Normal	Little cytoplasm
Cytoskeleton	Normal	Changes occur in cytoskeletal structure
Plasma membrane	Normal	Changes occur in plasma membrane
Growth	In control	Uncontrolled growth
Contact inhibition	present	Absent
Mortality	Mortal; through apoptosis	Immortal
Maturation of cells	Matures and undergo cell differentiation	Undifferentiated

Summary Introduction

To determine: The relevance of altered surface proteins to uncontrolled growth.

Introduction: Cancer is caused due to abnormal cell growth. This occurs due to several genetic and epigenetic alterations that cause uncontrolled proliferation of cells. The word tumor is used to refer swelling, but now it is used to describe the new growth or neoplasm (cancerous growth). The clinical manifestations of cancer are numerous and depend on the variety and intensity of symptoms.

Explanation of Solution

Some tumor or cancer cells do not express the antigens over their surface that causes failure in eliciting the immune response of the body. Altered expression of surface proteins of cells leads to the undesired changes in the cell interaction to its environment and response of surrounding cells. These cells divide rapidly and lose contact inhibition.

Cancer cells keep on growing beyond a monolayer and form a mass of cells that overlap with each other. They do not show anchorage-dependent growth. For a normal cell, cell division is limited to a monolayer. They stop cell division after forming a monolayer. Their growth is halted by contacts with neighboring cells as well as the availability of growth factors, nutrients, and substratum. After losing contact inhibition, the cell ceases to adhere within the tissue, which allows it to move away from the site of the original neoplasm.