CANCER

When What, and How

Background

• Cells divide and multiply as the body needs them. When these cells continue multiplying when the body doesn't need them, the result is a mass or growth, also called a tumor.

Background

• These growths are considered either benign or malignant.

• Each type of cancer is unique with its own causes, symptoms, and methods of treatment. Like with all groups of disease, some types of cancer are more common than others.

Cancer

• a malignant tumor of potentially unlimited growth that expands locally by invasion and metastasis

Cancer• Cancer is one of the most common diseases

in the world:• 1 in 4 deaths are due to cancer• Lung cancer is the most common cancer in

men• Breast cancer is the most common cancer in

women• There are over 100 different forms of cancer

Cancer• The division (mitosis) of normal cells is

precisely controlled. New cells are only formed for growth or to replace dead ones.

• Cancerous cells divide repeatedly out of control even though they are not needed, they crowd out other normal cells and function abnormally.

• They can also destroy the correct functioning of major organs.

Cancer Is One Outcome of A Runaway Cell Cycle

Licentious division - prostate cancer cells during division.

The Cell Cycle and Cancer

Neoplasm-Neoplasm- abnormal growth of cellsabnormal growth of cells BenignBenign neoplasms are neoplasms are not not cancerouscancerousEncapsulated; Do not invade Encapsulated; Do not invade neighboring tissue or spreadneighboring tissue or spread

MalignantMalignant neoplasms are neoplasms are cancerouscancerousNot encapsulated; Readily invade Not encapsulated; Readily invade neighboring tissuesneighboring tissues

May also detach and lodge in May also detach and lodge in distant places – metastasisdistant places – metastasis

Characteristics of Cancer Cells

Lack differentiation (control)Lack differentiation (control)Have abnormal nucleiHave abnormal nucleiForm tumorsForm tumorsMitosis controlled by contact Mitosis controlled by contact with neighboring cells – contact with neighboring cells – contact inhibitioninhibition

Cancer cells have lost contact Cancer cells have lost contact inhibitioninhibition

What causes cancer?• Cancer arises from the mutation

of a normal gene.

• Lack of apoptosis (self destruction)

• P53 and P 21 genes

• these genes could actually be mutated be chemotherapy

• Microtubules ( there are some drugs that targets them make the cell grow abnormaly

• P-Glycoprotien pump

• Angiogenesis (formation of blood vessels by VA GV)

• Metastasis (original tumor easily fragments

• Inflammation(chronic,infection can weaken our immune system that create environment for cancer

• Myc oncogene (easily mutated gene, from food, bacteria and virus)

• Exosomes (booms that inhibit the action of NK cells

• ER-ɑ and ER-ß( estrogen receptor cancer)

• Milieu(environment)

Carcinogens• Ionising radiation – X Rays, UV light

• Chemicals – tar from cigarettes

• Virus infection – papilloma virus can be responsible for cervical cancer.

• Hereditary predisposition – Some families are more susceptible to getting certain cancers. Remember you can’t inherit cancer its just that you maybe more susceptible to getting it.

Cell Cycle 4Cell

division

Mitosis

3DNA

repair

G21

Cell grows, doubles in size

G1

S

2Chromosome duplication

G2/M checkpoint

G1/S checkpoint

Signal Transduction• In normal cells, signals from outside cell can

– Activate tumor suppressor genes (turning off cell division) or

– Activate proto-oncogenes (turning  on  cell division)

• Signals can be proteins, hormones, or nerve signals

• May include steroids, pollutants, and other molecules

Process of Signal Transduction

• Signal binds to a receptor in plasma membrane

• Binding sets off series of interactions inside cell

• Signal molecule may remain outside cell• Binding of signal changes shape of

receptor and allows it to transmit signal to other proteins

• May alter gene expression

Outside cell

Receptor

Plasma membrane

Cytoplasm

Nucleus

Changes in gene expression

Signal molecule

Signal–receptor binding

Cellular response

Protein molecules

Tumor Suppressor Genes•Tumor suppressor genes produce proteins that

suppresses growth and proliferation.

•These are “loss of function” or recessive mutations.

•Being heterozygous enhances the probability of cancer but this will require a mutation in the corresponding other allele. e.g., it need to be homozygous for the gene.

•Tumor supressor genes include: (a) Proteins that regulate or inhibit progression through a cell cycle stage like CKI’s: p16, p21; (b) Receptors for secreted hormones/growth factors that function to inhibit proliferation: e.g., TGF-beta; (c) Restriction point (Rb) & check point (p53) control proteins.

G1

SG2

M

S

G2

M

G1

RB

RB

pi

E2F

E2F

Cyclin DCDK4

Cyclin ECDK2

Cyclin D

P21P21P21P21

Proto-OncogeneGrowth Factor

Tyrosine kinase receptor

RAS(G protein)

Protein kinases

Nucleus

Protein thatstimulates cell cycle

Transcription factor

Gene expression

Proto-Oncogene

CANCER CELLS ARE CHARACTERIZED BY GLOBAL ABERRATIONS IN THE NUMBER SIZE AND BANDING PATTERNS OF CHROMOSOMES GIVING RISE TO THE IDEA OF A “CHAOTIC GENOME” IN CANCER CELLS.

Chromosome painting of normal diploid human cells

Chromosome painting of an osteosarcoma cell line (MG-63)

What are the different kinds of Cancer?

• The four most common cancers are:• Breast Cancer• Colon Cancer • Lung Cancer • Prostate Cancer

What are the different kinds of Cancer?

• Cancers of Blood and Lymphatic Systems:• Hodgkin's Disease • Leukaemia • Lymphomas • Multiple Myeloma • Waldenström's Disease

What are the different kinds of Cancer?

• Cancers of Digestive Systems: • Head and Neck Cancers • Esophageal Cancer • Stomach Cancer • Cancer of Pancreas • Liver Cancer • Colon and Rectal Cancer • Anal cancer

What are the different kinds of Cancer?

• Cancers of Urinary system: • Kidney Cancer • Bladder Cancer • Testis Cancer • Prostate Cancer

What are the different kinds of Cancer?

• Miscellaneous cancers: • Brain Tumors • Bone Tumors • Nasopharyngeal Cancer • Retroperitoneal sarcomas • Soft Tissue Tumors • Thyroid Cancer • Cancers of Unknown Primary Site

Cancer Treatment

• Chemotherapy treatment

• uses medicine to weaken and destroy cancer cells in the body, including cells at the original cancer site and any cancer cells that may have spread to another part of the body.

Cancer Treatment

• Chemotherapy treatment

• or "chemo," is a systemic therapy, which means it affects the whole body by going through the bloodstream.

• In some cases, chemotherapy is given before surgery to shrink the cancer

Cancer Treatment

• Radiation therapy (also called radiotherapy)

• Like surgery, radiation therapy is a local treatment; it affects cancer cells only in the treated area. Radiation can come from a machine (external radiation).

Cancer Treatment

It can also come from an implant (a small container of radioactive material) placed directly into or near the tumor (internal radiation). Some patients receive both kinds of radiation therapy.

Cancer Prevention

• Healthy lifestyle– Exercise and proper breathing– Balanced diet– Complete rest and sleep– Water (8 to 10 glasses daily) – Eating Fruit on an empty stomach

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