Cancer

Mutations Mutations are permanent changes in the DNA of the cell

Types of Mutations Duplication: an extra copy of a gene is made and inserted into the chromosome. Original Chromosome: shows the normal order of the genes in a chromosome.

Types of Mutations Deletion: a gene or part of a gene is not copied so it is missing from the chromosome. Original Chromosome:

Types of Mutations Insertion: a gene or part of a gene is inserted into a chromosome where it doesn’t belong. Original Chromosome:

Types of Mutations Inversion: genes or parts of genes are inserted into a chromosome backwards. Original Chromosome:

Mutations can be caused by Carcinogens Examples include: a) chemicals such as benzene from cigarette smoke or nitrites from processed meats b) radiation such as ultraviolet (UV) rays from the sun or X-rays c) infections such as the human papilloma virus (HPV) that can cause cervical cancer

Mutations in the DNA may cause Cancer some mutations are harmless some mutations are lethal and kill the cell; some mutations effect critical genes and may cause cancer

Cancer begins when a mutation turns on or off critical genes that control the rate of cell division (these genes are called “oncogenes”); these mutations make the cell divide rapidly and out of control How Does Cancer Start?

Abnormal Cell Division: the DNA in a cell is mutated (changed); may be random or from a carcinogen. Cancer: One or more of the mechanisms that control cell division are turned off. The cell divides rapidly and incorrectly. Apoptosis: the cell recognizes that it is damaged and commits “cellular suicide”. The cell dies. The mutation may be harmless or even beneficial. The cell continues to function as well as, or better, than before. This change is passed to the daughter cells. If the mutation happens in a sperm or egg cell, then it will be passed on to all future generations. Normal Cell

Tumours are swellings formed by the abnormal growth of cells tumour cells do not respond to normal signals that control cell division and cell growth the suffix “oma” indicates a tumour eg. carcinoma, lipoma or melanoma the study of tumours is called oncology Not all tumours are cancerous

Benign Tumours tumours that stay in one place and do not spread to other parts of the body are usually smooth, round and encapsulated (surrounded by a membrane or capsule) these tumours do not cause cancer and can be removed surgically

Benign fibromas in the uterus

Benign lipoma on the internal surface of the intestine

Benign liver tumour (The tumour is a green colour because it is producing bile.)

Benign Stomach Tumour

Malignant Tumours malignant tumours are cancerous because they spread to other parts of the body “cancer” comes from the Latin word for crab because cancer cells cling tightly to whatever tissue they attach themselves are usually irregularly shaped like a cauliflower or ulcer

Malignant liver tumours

Malignant Tumour of the Uterus

Cervical Cancer (on the Cervix)

Tumours of the Intestine

Bone Cancer on the Femur

Thyroid Cancer

Melanoma (Skin Cancer)

Signs of Melanoma (Skin Cancer) The ABCDEs:  Asymmetrical  Borders are ragged or uneven  Colour varies  Diameter is larger than a pencil’s eraser  Evolving or changing over time

Cancer Cells grow and divide uncontrollably often crowd together tightly are large and irregularly shaped have large, dark staining nuclei may have more than one nucleus per cell undergo frequent and abnormal mitosis secrete chemicals that cause new blood vessels to grow and bring them nutrients

Abnormal Mitosis in a Cancer Cell This cancer cell has a “tripolar” spindle (three sets of spindles).

Abnormal Mitosis in Cancer Cells

Testicular Cancer Cells

Skin Cancer Cells

Breast Cancer Cells

Normal Blood Cells There should be about one white blood cell for every 600 red blood cells

Blood Cells in Leukemia There are too many white blood cells (leukocytes).

Stages in Cancer Development 1. Cancer begins as a single mutated (genetically altered) cell. 2. This cell divides rapidly and uncontrollably, which is called “hyperplasia” (fast growth). 3. Because of abnormal mitosis, the cancer cells don’t divide properly, which is called “dysplasia” (abnormal growth).

Stages in Cancer Development 4. The tumour grows “in situ” (where it started) 5. The tumour becomes invasive. Pieces of the tumour break off and spread to other tissues, which is called “metastasis”. The tumour also secretes chemicals to cause new blood vessels to form to bring the tumour nutrients.

Stages of Cancer Development

Stages in Cancer Development

Cancer Treatment: Chemotherapy chemotherapy (“chemo”) is the use of drugs to slow down or stop cell division chemotherapy slows down cell division in ALL rapidly dividing cells, both cancer cells and normal cells that divide rapidly such as cells lining the stomach and intestines, hair follicles and blood cells the goal of chemotherapy is to kill more cancer cells than normal cells, and hope that the normal cells will be able to recover later

Cancer Treatment: Radiation radiation is the use of high energy waves and particles to kill rapidly dividing cells radiation damages the cell’s DNA so the cell can not divide properly, so it dies radiation is focused on the tumour, so its cells get the highest dose normal cells around the tumour receive lower doses of radiation, so they should recover after the treatments are over