Module 2 - BIO 11 - Unit 2

Stage 4 Cancer

- Cancer has fully metastasized and has spread to organs outside of the breast - In breast cancer, this typically includes the lungs, heart, brain, and liver. - Type of cancer is often called incurable, but medical advances are being made to extend the lifespan of individuals with this stage

How does cancer disrupt organ function

- as a tumor forms, begins to take up space in organ - this can block ducts, blood vessels, or lymphatic vessels needed for organ to function - most cells of a tumor require oxygen and nutrients, and may cause fewer resources for other cells

Cancer cell appearance

- cancer cells often look very different that surrounding neighbors and have an irregular shape - nuclei of cancer cells different and typically larger - nuclei may vary in shape and size

Negative feedback

- type of regulation in bio systems in which the end product of a process in turn reduces stimulus of that same process - occurs in blood sugar regulation, pH, and levels of chemicals in the blood

Example of cancer disrupting organ function

1. Breast cancer that has metastasized to the lungs can block airways, reducing oxygen 2. Cancer in the brain can place pressure on areas necessary to regulate body functions 3. Cancer in the bone marrow may prevent WBC from forming, leaving body open to infection

Organs involved in homeostasis

1. Digestive System 2. Respiratory system 3. Cardiovascular system 4. Urinary system 5. Liver & Kidneys 6. Heart

Stage 3A cancer

1. Either the tumor is less than 2 cm but has spread to more than four nearby lymph nodes, or tumor is larger than 5cm, but has spread to lymph nodes near breastbone or arm.

Stage 2A Cancer

1. Either tumor is smaller than 2cm (or cannot be detected) and cancer cells have been detected in multiple lymph nodes, or tumor is 2-5 cm in size but has not spread to lymph nodes.

What questions do oncologists ask?

1. How large is the tumor? 2. Has the tumor begun to invade nearby tissues? 3. Is the cancer located in nearby lymph nodes? 4. Has cancer moved to any other organs of body?

Stage 3C cancer

1. The tumor (regardless of size) has spread either to area of collar bone or to more than ten lymph nodes.

Stage 3B cancer

1. The tumor (regardless of size) has spread either to the wall of the breast or the skin on breast and has infected more than nine lymph nodes. Often, this stage of cancer also has characteristics of forming swelling, inflammation, or ulcers on the breast.

How does cancer affect homeostasis

As cancer disrupts the operation of organs, it has ability to interfere with body's ability to regulate internal environment.

Are benign or malignant tumors more dangerous

Benign tumors may be dangerous if their growth interferes with organs, malignant tumors present a much greater threat to our bodies

Stage 0 cancer

Cancer cells are located in a very small area. If tumor is detected early, and has not begun to invade surrounding tissues

Stage 3 Cancer

Cancer has become more invasive and is beginning to affect more of the tissues of the breast and surrounding tissues but has not yet spread to distant organs of the body.

Stage 1 cancer

If the tumor has begun to invade surrounding tissues

Sentinel biopsy

Lymph node that is closest to tumor is referred to as the sentinel lymph node, so biopsy is called this

Stage 2B Cancer

Size of tumor has increased to 2-5 cm and cancer cells have been detected in nearby lymph nodes.

Metastasis

The spread of cancer cells beyond their original site

Stage 1A cancer

Tumor is small (usually less than 2cm), but has not spread to any nearby lymph nodes

Stage 1B cancer

Tumor is smaller than 2 cm (can't be detected), but small groups of cancer cells are found in a few of the surrounding lymph nodes

Why do cancer cell nuclei look darker?

Usually because of mutations that have increased amount of DNA in nucleus

Lymphatic vessels

are responsible for removing excess fluid from tissues, and participate in immune response

What are the two types of tumors

benign and malignant

How do physicians determine if cancer has metastasized?

by taking small samples of tissue from lymph nodes surrounding cancer, which is called a biopsy.

Capillary function

carry nutrients and oxygen to cells, and remove waste materials

Pathologists

doctors who diagnose disease based on lab results, use the TNM classification

How are cancer stages determined

· Cancer diagnoses use a numerical system to indicate degree to which the cancer spreads · Based on a 0-4 or 1-4 grade, as well as subcategories such as 1A or 1B. · Staging of cancer done by an oncologist - a doctor who specializes in treatment of cancer

Stage 2 Cancer

· Cancer is considered to be invasive. The tumor begins to grow in size, but still located entirely in one area, such as the breast.

Mortality rates of cancer

· Mortality rates from cancer are dropping by almost 1.8% per year for men, and 1.4% per year for women. Cancer will claim 610,000 lives this year.

What is Homeostasis

· Stabilization of internal environment around conditions · Conditions include body temp of 37 degrees, and pH of body fluids is 7.4. · Maintaining those conditions important because enzymes are optimized during these conditions - homeostasis result of negative feedback mechanisms

Benign tumors

- Cells in a benign tumor often closely resemble those in surrounding tissue - Key characteristic of a benign tumor is that it is localized to one tissue type and has not invaded surrounding tissues - A mole (nevus) is an example of a benign tumor of the skin

Malignant tumors

- Cells in a malignant tumor don't resemble other cells of tissue and are very unspecialized - Frequently differ in appearance even within tumor itself - have ability to invade other tissues, and possibly move to other locations in the body.

Proteinase

- Malignant tumor meets some resistance as it grows, and releases enzyme proteinase - Proteinase digests protein molecules and allows cells of tumor to move into surrounding tissues

General characteristics of cancer cells

- accumulate mutations in its genetic info over time - due to rapid cell division, accumulates more and more mutations, or makes mistakes during cell division that result in an increase in total amount of DNA in cell - mutations and increase in DNA content accelerate changes discussed ahead

Why are cancer cells immortal

- an enzyme called telomerase is active within the cell - telomerase repairs at end of chromosome, effectively making cell immortal - allows cell to accumulate more mutations over time

Cancer cell division & needing nutrients

- cancer cells rapidly divide, meaning they require plentiful amounts of oxygen and nutrients - as tumor grows, cells in a center of tumor have a harder time getting required materials - undergo angiogenesis

Angiogensis

- cancer cells release specialized growth factors that cause local capillaries of circulatory system to grow toward tumor - tumor cells release signals that promote growth of new blood vessels, which supply tumor with nutrients

How are cancer cells less specialized

- cells of our body become more specialized over time because of cell signaling and chemical signals - cancer cells undergo a reverse process - as a cell accumulates mutations, becomes less specialized, no longer functions as part of surrounding tissue - if it continues to divide, it will become a mass of unspecialized tissue called a tumor

Why does limitation of cell division matter

- cells only divide a limited number of times before undergoing apoptosis (telomeres shortening) - with each cell division, there is a chance that DNA may accumulate a detrimental mutation, and by limiting number of cell divisions, chances of cell becoming cancerous is reduced

Normal cell appearance

- normally cells have a distinct appearances, and is difficult to pick out any differences between individual cells - due to process of cell division, cells genetically identical and carry out same genetic instructions in tissue - nuclei do not vary

Cell signaling

- series of complex interactions between cells that help specialize cells - cells become specialized by cell signaling and chemical signals from other organs of body - those interactions turn sets of genes on, and others off, establishing identity and role of cell

Cancer Alters Body Chemistry

- some organs in body play an important role in regulating chemical compositions - EX: tissues in bone help establish blood calcium levels, so bone cancer can disrupt calcium homeostasis, causing calcium levels to rise Those high levels of blood calcium could lead to coma

How cancer cells move to other parts of body

- when malignant tumor invades tissue, can come in contact with local capillaries or lymphatic vessels (both part of transport system) - if cells of tumor get into these, can be transported to other areas of body where they can undergo angiogenesis to form new tumors (metastasis)

TNM Classification of cancer

· Score is based on three factors: 1. T: the size of the tumor. A Tx indicates that the tumor can't be found, while T1-4 indicates relative size of tumor 2. N: number of lymph nodes in which cancer is detected. Example: N3 would indicate that cancer cells were detected in three lymph nodes. 3. M: whether the cancer has metastasized to other organs of the body. This is given as a M0 (no metastasis observed) or M1 (the cancer has moved to distant organs or tissues).