CANCER

Who gets cancer? *No social or economic boundaries *All populations *All ages *All demographics *All races *Everyone is equally affected!

Characteristics of cancer cells Three basic characteristics: (1) The first is that they have lost the ability to undergo apoptosis, or programmed cell death. (2) Cancer cells have lost the ability to stop dividing. (3) Telomeres are structures that cap off the ends of DNA. Each time a cell divides during adult life, the telomeres get shorter. When they get too short, repressor genes tell the cell to stop dividing. Telomeres are activated by telomerase, which is inactive by adulthood. Telomerase activation is a key step in developing cancer (90% of all cancer cases telomerase is active).

Types of cancer Three basic categories: carcinomas, sarcomas and leukemias/lymphomas Both carcinomas and sarcomas are solid tumors, or tumors consisting of a dense collection of cancer cells that has its own blood supply. leukemia and lymphoma are malignancies originating in immune or hematopoeitic cells (blood cells) and can be found in patients representing a wide age range. These cancers are commonly referred to as disseminated cancers as they do not form masses of cells, but instead are found throughout the vascular system.

Tissue Pathology Physicians who specialize in the study of disease are called pathologists. They focus on diagnosing the disease, rather than treating it. Use a combination of anatomical and histological observations to determine the nature and severity of the disease.

Diagnosis Part of the diagnosis process often includes taking biopsies (tissue samples) of diseased organs/tissue *Tissue can be obtained through surgical removal of external skin or surgery (excisional) *Tissue can also be removed via biopsy needles to minimize invasive procedures. (incisional biopsy)

Diagnosis of cancer Cancers can be seen on Xrays

Diagnosis of cancer Oligodendrogliomas diagnosed via MRI

Histological changes Environmental factors, such as smoking or tanning, can cause tissues to change. Genetic factors can also cause tissue to grow abnormally Not known what causes the cells to mutate or divide with all genetic cases of cancer

Histological change: dysplasia First abnormality seen during histological change. Dysplasia is a change in the normal size, shape, and organization of tissue cells. Usually a response to chronic irritation or inflammation (cigarette smoke, sun exposure, etc) Changes in tissue are reversible!

Histological change: metaplasia Epithelial and connective tissues may undergo more radical changes in structure due to division and differentiation of stem cells. Metaplasia is a structural change that dramatically alters the character of the tissue. EX: heavy smoking over time leads to epithelial cells losing their cilia altogether

Histological change: metaplasia As metaplasia progresses, the epithelial cells produced by stem cell divisions no longer differentiate into ciliated cells. They begin to form stratified squamous epithelium that provides greater resistance to drying and chemical irritation. Remember stratified squamous functions to protect, so the body tries to protect the underlying tissues, but can’t protect all parts of the respiratory tract. Metaplasia is reversible!!!

Histological change: anaplasia In anaplasia, tissue organization breaks down. Tissue cells change shape and size, becoming unusually large or small. The tissue cells become tumor cells, reproducing at a faster rate. Not all cell divisions occur in the normal way; many tumor cells have abnormal chromosomes. Anaplasia is irreversible!

Healthy lung vs smokers lung

Staging of cancers

Top ten deadliest cancers 1. Lung Cancer 2. Colon/rectal cancer 3. Breast cancer 4. Pancreatic cancer 5. Prostate cancer 6. Leukemia 7. Non-Hodgkin Lymphoma 8. Liver cancers 9. Ovarian cancer 10. Esophageal cancer