pubh bio quiz 3

Cancer

A group of diseases in which abnormal cells grow uncontrollably, can arise in almost any tissue, and may spread.

Cancer rank among US causes of death

Second, according to the lecture.

Modifiable cancer risk factors

Tobacco use, excess body weight, poor diet, and certain infections.

Non-modifiable cancer risk factors

Age and inherited genetic mutations.

Galleri test

A blood test looking for cell-free DNA methylation patterns that may signal 50+ cancers; it does not diagnose cancer.

Galleri test cost in lecture

Approximately $900.

Cancer linked to infections in 2024

Lecture reports about 2.3 million new cases, roughly 1 in 8 worldwide, linked to infections.

Examples of infection-associated cancers

HPV-associated cancers and Helicobacter pylori-associated cancers.

Carcinogen

A substance or agent that can initiate or cause cancer in humans.

Aflatoxin

A natural carcinogen produced by a fungus on improperly stored grains and nuts.

Examples of man-made carcinogens

Asbestos, tobacco smoke, and certain industrial chemicals.

How carcinogens can cause cancer

They can damage DNA, causing mutations that drive cancer development.

Endocrine disruptor

A chemical that mimics, blocks, or alters the body's hormone system.

Potential effects of endocrine disruptors

Developmental, reproductive, neurological, immune, and hormone-sensitive cancer effects.

Examples of endocrine-disruptor sources

Pharmaceuticals, dioxins, PCBs, DDT/pesticides, BPA, plastics, cans, detergents, flame retardants, cosmetics, toys, and food.

Cancer development: initiation

First stage; spontaneous or carcinogen-caused mutations occur.

Cancer development: promotion

Environmental factors such as diet or endogenous factors such as hormones promote growth.

Cancer development: progression

Additional genetic or epigenetic changes make cancer more advanced.

Metastasis

Cancer cells leave the original tumor, travel through blood or lymph, and form tumors elsewhere.

Cancer cell self-sufficiency in growth signals

Cancer cells divide without normal signals telling cells to grow.

Insensitivity to anti-growth signals

Cancer cells ignore signals that normally stop division.

Unlimited replicative potential

Cancer cells bypass normal senescence and can continue dividing.

Evasion of apoptosis

Cancer cells resist programmed cell death even when damaged or abnormal.

Angiogenesis

Formation of new blood vessels; tumors stimulate it to obtain oxygen and nutrients.

Tissue invasion

Cancer cells invade surrounding tissues.

Cancer grade

How abnormal or undifferentiated cancer cells look microscopically.

Low-grade cancer

Cells look more like normal cells.

High-grade cancer

Cells look more abnormal and may grow or spread faster.

Cancer stage

How far cancer has spread, considering tumor size, lymph nodes, and distant metastasis.

Carcinoma

Cancer arising from epithelial tissues such as skin, glands, or organ linings.

Sarcoma

Cancer arising from mesenchymal tissues such as bone, cartilage, fat, or muscle.

Lymphoma

Cancer beginning in lymphatic/immune-system tissues.

Leukemia

Cancer involving blood-forming tissues and blood cells.

Myeloma

Cancer involving plasma cells, a type of immune cell.

Tumor microenvironment

Immune cells, fibroblasts, molecules, and blood vessels surrounding a tumor that influence its growth and spread.

How cancer evades immunity

It can resemble normal cells, send "back off" signals, or create a microenvironment that blocks immune attacks.

How immunotherapy may help

Some treatments help immune cells better detect and kill cancer cells.

Why cancers differ between people

Each person's cancer can have a unique combination of genetic changes affecting treatment response.

Proto-oncogene

A normal gene that regulates/promotes controlled cell growth.

Oncogene

A mutated or overactive proto-oncogene that drives uncontrolled cell growth.

How proto-oncogenes become oncogenic

Point mutation, gene amplification, chromosomal translocation/rearrangement, or epigenetic changes.

Proto-oncogene examples from lecture

RAS, MYC, and HER2.

HER2 amplification

Can drive aggressive breast tumor growth; lecture says about 20% of breast cancers have HER2 amplification.

Trastuzumab (Herceptin)

A targeted therapy that blocks HER2 and can improve survival and reduce recurrence.

Tumor-suppressor gene

A gene that restrains cell growth or helps prevent cancer; loss of function can enable uncontrolled growth.

TP53

A tumor-suppressor gene described as a brake on cell growth.

RB

A gatekeeper tumor-suppressor gene regulating cell cycle/cell growth.

Caretaker gene

A gene that maintains genome stability through DNA repair, cell-cycle checkpoints, or telomere stability.

Gatekeeper gene

A gene that directly regulates cell growth, cell cycle, or apoptosis.

Genomic instability

An increased tendency for DNA/genetic changes to accumulate.

Why cancer risk rises with age

Cancer-causing changes accumulate over time, while DNA repair mechanisms can become less efficient.

Retinoblastoma

A rare childhood retinal tumor associated with RB1 mutations; lecture estimates 1 in 20,000 and 3% of childhood cancers.

Cervical cancer key infectious cause

Persistent infection with high-risk human papillomavirus (HPV).

HPV overview

A group of about 200 viruses; most infections clear, but some high-risk types cause cancers and some types cause genital warts.

HPV infection course

Often clears without symptoms, especially in younger people; persistent infection can raise cancer risk.

HPV-related cancer burden in 2019

Lecture reports about 620,000 cancer cases in women and 70,000 in men attributable to HPV.

HPV cancer prevention

HPV vaccination, screening for precancerous lesions, and appropriate follow-up/treatment.

Pap test

Cervical screening test that can detect precancerous changes.

Why early cervical screening matters

It can identify precancerous lesions before invasive cancer develops.

HPV vaccine recommendation as stated in slides

Lecture slide says recommended for males through age 21 and females through age 26; use current clinical guidance for real decisions.

Breast ductal carcinoma in situ (DCIS)

An early breast cancer in which malignant cells in milk ducts remain in place (in situ).

Breast cancer mortality trend

Lecture says female breast-cancer death rates peaked in 1989 and then fell by about 42% as of the slide's reference period.

Breast cancer risk: dense breasts

More cells may become abnormal and dense tissue makes mammograms harder to interpret.

Breast cancer inherited susceptibility genes

BRCA1 and BRCA2 are examples of inherited cancer-susceptibility genes.

Breast cancer hormonal/reproductive risk examples

Starting menstruation before 12 and menopause after 55 lengthen exposure to reproductive hormones, as described in lecture.

Skin cancer primary prevention

Avoid excessive UV exposure, use SPF 30+ sunscreen, and wear protective clothing/hats.

Cancer prevention through immunization

Vaccination against carcinogenic viruses such as HPV can prevent some cancers.

Cancer prevention through safer sex

Condom use can reduce exposure to some sexually transmitted carcinogenic infections, though it does not eliminate HPV risk.

Cancer prevention through chemical regulation

Reduce exposure to carcinogenic chemicals through regulation and environmental protections.

Cancer screening examples in lecture

Cervical cancer: Pap/HPV testing; screening programs can identify disease earlier.

Targeted therapy

Personalized/precision treatment aimed at a specific molecular feature of a tumor.

Why targeted therapy may not work for everyone

Not every tumor has an identified actionable mutation, and tumor biology/resistance varies.

CAR-T cell therapy

Immunotherapy in which a patient's T cells are modified to express a special receptor that targets cancer cells.

Cancer public health challenge: causes

Many cancers have unknown or multifactorial causes; environmental, genetic, microbial, and behavioral factors interact.

Cancer public health challenge: risk prediction

Identifying high-risk people is difficult; access, education, income, and diverse populations complicate risk profiling.

Cancer public health challenge: rare/resistant cancers

Some cancers, including pancreatic, brain, late-stage, rare, and pediatric cancers, have limited or resistant treatment options.

Cancer health equity challenge

Prevention and early detection do not reach all groups equally; culturally tailored scalable interventions and policy support are needed.

Cancer: inherited mutation vs inherited cancer

A person may inherit a predisposition mutation; this does not mean cancer itself is inevitably inherited or will develop.

Why cancer is usually not fixed by one mutation

It commonly involves multiple accumulated genetic and epigenetic changes and interactions with the tumor environment.

Positive cancer prevention approaches from lecture

UV protection, immunization against carcinogenic viruses, condom use, chemical regulation, and early detection.

Diabetes mellitus

A chronic condition in which the body cannot make enough insulin or use it effectively, leaving excess glucose in blood.

Insulin

A hormone made by pancreatic beta cells that helps move glucose from blood into cells for energy/storage.

Glucose

A six-carbon sugar and the primary fuel source for the body's cells.

Homeostasis

The body's ability to maintain a relatively stable internal environment despite external change.

Dynamic equilibrium

A stable state maintained by balancing inputs and outputs; not a completely unchanging state.

Sensor in homeostasis

Detects a change or signal.

Control center in homeostasis

Receives sensor information and sends instructions for a response.

Effector in homeostasis

Carries out the response that helps restore the desired condition.

Negative feedback

A response that counteracts a change and returns a variable toward its normal range.

Positive feedback

A response that amplifies a change; less common and used in specific processes such as childbirth.

Negative feedback example: blood glucose

Rising glucose triggers insulin release; insulin promotes uptake/storage and blood glucose falls.

Negative feedback example: temperature

The hypothalamus integrates temperature signals and activates effectors to adjust body temperature.

Endocrine gland

A ductless gland that releases hormones directly into the bloodstream.

Exocrine gland

A gland that releases products through ducts, such as sweat, saliva, tears, milk, or mucus.

Hormone

A signaling molecule made by endocrine cells/glands that regulates body functions, often over longer time scales.

Hormone signaling key events

Reception → signal transduction → response.

Ways endocrine signaling can be disrupted

Hormone production, transport/availability, or receptor/signaling response can be disrupted (see lecture diagram).

Glucose sources

Food carbohydrates are digested into monosaccharides; the liver also stores and releases glucose.

Hyperglycemia

Blood glucose that is too high.

Hypoglycemia

Blood glucose that is too low.