Cancer

• CA cells do not have a cell membrane
• Cell membranes protect the cell
• Limits cell growth
• Determines what type of cell its gonna be

Malignant neoplasm - new growth or formation

• Nutrients
• Oxygen
• Carry out metabolism
• Carry out excretion
• Undergo a reproductive process

Increase in size of normal cells (heart muscle)

Increase in number of cells

Any new or continued cell growth NOT NEEDED for normal development or replacement of dead or damaged tissues is termed NEOPLASIA and is always considered abnormal

• Slow growing
• Localized
• Encapsulated with well-defined borders
• Easily removed
• Non-malignant

• Aggressive growths that INVADE and DESTROY surrounding tissues
• Can lead to death unless interventions taken
• Own blood supply
• Rapid growth

• *Have limited cell division
• Undergo mitosis to develop normal tissue & replace lost or damaged normal tissue
• Divide only when optimal body conditions & nutrition exist

• *Show specific morphology
• Each cell type has a distinct & recognizable appearance, size, & shape

• *Have a small nuclear-cytoplasmic ratio
• The nuclear space is small in proportion to the cytoplasmic space

• *Perform specific differentiated functions
• Every cell must perform at least one special function to contribute to whole body homeostasis

• *Adhere tightly together
• Cells make & secrete cell-surface proteins that allow cells to bind closely & tightly together (cling together)

• *Are nonmigratory
• Cells do not wander from one tissue to another
• Exception - erythrocytes & leukocytes

• *Are contact inhibited
• A cell will divide only as long as it hase some surface that is not in direct contact with another cell
• It no longer ungoes mitosis if it is in direct contact on all surface areas with another cell membrane

• G₀ Phase: Resting - not in cell cycle
• G₁ Phase: preparing for division - taking extra everything - 18 hours
• S Phase: DNA duplicates - DNA synthesis - 20 hours
• G₂ Phase: Protein & RNA synthesis
• Mitosis: prophase, metaphase, anaphase, telophase - single cell splits into 2 identical cells

• Differentiated during embryonic development
• This is a normal cell characteristic
• Daughter cells - look just like mom - same characteristics
• Increased specialization of cells & tissues
• From immature to complex
• A well-differentiated cell is mature & functions properly - looks like mom
• An undifferentiated cell is immature & does not do its work - malignant

Carcinogenesis - Activation of proto-oncogenes into oncogenes

• Suppressor genes -
• *Prevents cells from dividing
• *Take control over proto oncogenes
• *Maintains control over cell cycle

Carcinogen meets up with suppressor gene DNA - alters it - turns proto oncogene into oncogene

• Genetic research has focused on proto oncogenes
• These are genes that promote rapid growth in the undifferentiated cell of the fetus - as the cells begin to differentiate, these genes are "turned off"
• They have no other apparent function in the life cycle
• Mutation of proto oncogenes produces oncogenes
• An oncogene (small segment of the DNA) can transform normal cells into malignant ones and activate the process of cell division
• Proto oncogenes can be activated to become oncogenes by two processes
• *Viral related - certain viruses can alter cell DNA control of the proto-oncogenes
• *Carcinogenesis - some proto-oncogenes can become active oncogenes when spontaneous or chemically induced initiation occurs - this results in uncontrolled reproduction of mutant cells during the promotion phase

The process of changing a cell with normal appearance & function into a cell with malignant characteristics (malignant transformation)

• 4 Steps:
• Initiation
• Promotion
• Progression
• Metastasis

• Initiators such as chemicals, physical factors, and biological agents escape normal enzymatic mechanisms and cause alterations in the genetic structure of the cellular DNA
• Alterations are irreversible but usually not significant until the second step

• Repeated exposure to promoting agents causes the expression of abnormal or mutant genetic information
• The cells then begin to produce mutant cell populations
• Agents that promote or initiate cellular transformation are referred to as carcinogens.