Cell Biology and Cancer What is cancer In

Cell Biology and Cancer

What is cancer? • In simple terms, cancer is a group of more than 100 diseases that develop across time and involve the uncontrolled division of the body’s cells. • Cancer begins when a cell breaks free from the normal restraints on cell division and begins to follow its own agenda for proliferation (multiply).

What is a tumor? • A tumor is a mass of cells. • In situ cancer- means the abnormal cells remain within the tissue in which it originated. • Invasive cancer- when the abnormal cells begin to invade nearby tissues.

Malignant • An invasive tumor is said to be malignant. The cells shed in to the blood or lymph from a malignant tumor. • This likely establishes new tumors throughout the body, also known as metastases. • Tumors threaten an individual's life when the growth disrupts the tissues and organs.

3 stages of tumor development Cell with genetic mutation, hyperplasia, dysplasia, in situ cancer, invasive cancer.

Research • Over the last 3 decades, research has revolutionized our understanding of cancer. • Largely due to the application of the techniques of molecular biology. • Today we know cancer is a disease of molecules and genes • Our increasing understanding of these genes makes it possible for development of new strategies for preventing, forestalling and even correcting the changes that lead to cancer.

Clues from epidemiology • In 1775, a high incidence of scrotal cancer was described among men who worked as chimney sweepers. • In the mid-1800’s, lung cancer was observed at alarmingly high rates among miners in Germany. • At the end of the 19 th century, using snuff and cigars was thought to be closely associated with cancers of the mouth and throat.

• These observations and others suggested that the origin or causes of cancer may lie outside the body, and more importantly, they could be linked to identifiable and even preventable causes. • These ideas led to a widespread search for agents that might cause cancer. • An early notion, prompted by the discovery that bacteria caused a variety of human diseases, suggested cancer was an infectious disease.

• Another idea was that cancer arises from chronic irritation of tissues. • This view received strong support with the discovery of X-rays in 1895 and the observation that exposure to this form of radiation could induce localized tissue damage, which could lead in turn to the development of cancer. • Another view is that it is hereditary.

• In 1910, a submicroscopic agent was isolated from a chicken tumor and found that it could induce new tumors in healthy chickens. • This theory led scientists to find out that an agent known as the Rous Sarcoma virus is one of several viruses that can act as a causative factor in the development of cancer.

Clues from cell biology • Cancer cells are indigenous cells— abnormal cells that arise from the body’s normal tissues. • All malignant tumors are monoclonal in origin (cells are derived from a single clone).

Development of cancer • The development of cancer occurs as a result of a series of clonal expansions from a single ancestral cell. • Although a tumor is monoclonal, it may contain a large number of cells with diverse characteristics.

Normal cells vs. cancerous cells • Cancerous cells look and act differently from normal cells. • In normal cells, the nucleus is only 1/5 th the size of the cell. • In cancerous cells, the nucleus may occupy most of the cells volume. • Tumor cells have lost their restraints on growth that characterize normal cells.

Cancer Trends Progress Report (CTPR) - 2007 Update • • • Measure. Trend. PREVENTION Age at smoking initiation. Stable Youth smoking. Falling Adult smoking. Falling Quitting smoking. Stable Health professional advice to quit smoking. Falling Secondhand smoke. Environmental Tobacco Smoke NSC Smoke-free work environment Rising Smoke-free indoor air laws. Rising Fruit & vegetable consumption. NSC Red meat consumption Stable

• • • Fat consumption Stable Alcohol consumption. Rising Weight (both sexes) Healthy weight. NSC Overweight. Stable Obese. NSC No leisure time physical activity. NSC Sun protection. Falling Pesticide levels in the blood. Rising Dioxin levels in the human body. Falling

EARLY DETECTION • • • Breast cancer screening. Falling Cervical cancer screening. Falling Colorectal cancer screening. Fecal Occult Blood Test (FOBT)Falling • Endoscopy. Rising • Colorectal test use. Rising

DIAGNOSIS Ø Incidence • All cancers. Falling • White. Falling • Black. Falling • Hispanics. Falling • American Indian/Alaskan Natives. NSC • Asian/Pacific Islanders. Falling

Four most common cancers • • Prostate. Stable Female breast. Falling Colorectal. Falling Lung and bronchus. Falling

Cancers that are increasing • Non-Hodgkin lymphoma. Rising • Melanoma of skin (White only)Rising Ø Stage at diagnosis Ø Colon. Falling Ø Female breast. Stable Ø Rectum. Falling Ø Cervix. NSC Ø Prostate. Falling

Breast cancer treatment • Mastectomy. Falling • No surgery. Rising • BCS with radiation. NSC • BCS without radiation. Rising • Multiagent chemotherapy. Rising Ø Colorectal cancer treatment. Rising

Life after cancer • • • Survival: All cancers. Rising Prostate. Rising Female breast. Rising Colorectal. Rising Lung and bronchus. Rising

End of life (all cancers) • • • All cancers. Falling White. Falling Black. Falling Hispanic. Falling American Indian/Alaskan Natives. Stable Asian/Pacific Islander. Falling

Mortality of the 4 main cancers • • Prostate. Falling Female breast. Falling Colorectal. Falling Lung and bronchus. Falling