Author Notes

hello and thank you for visiting! currently preparing for the unit 3 test which is very soon and i’m hoping to get a decent score other than a 66% on the other two tests (yeah idk why i suck).. anyways, good luck and happy studying!!!

• use the “test me” feature to test yourself on this knowledge!

﹙✦﹚﹒﹒note that there are abbreviations used throughout this guide :]

﹙Overview﹚

unit 3 is a deep dive into the world of cancer, discussing the process of diagnosis, treatment, creating interventions, and prevention that takes place as cancer continues to end the lives of many. this will provide review of all the concepts in unit 3, including the calculations, biotechnological processes and analyzations of data as scientists and medical professionals.

╭ Other Resources :

:: unit 3 terms ﹒﹒ a knowt deck i made of the key terms of this unit (only 3.1-3.2 atm) !

:: cancer prefixes ﹒﹒ my teacher said it’ll help with the unit test so.. yeah its there

﹙3.1 - Detecting Cancer﹚

✦﹒diagnostic imaging helps with the diagnosis of cancer by producing images in your body

• radiology is a branch of medicine in diagnostic imaging

• these include:

  • x-ray - produces 2D imgs of the inside of the body by sending electromagnetic radiation rays thru the body

  • CT scans - also computerize [axial] tomography, produces multiple sectional 3D/cross section imgs of the body using ionization radiation

  • MRI scans - also magnetic resonance imaging, uses powerful magnets and radio waves instead of radiation to produce detailed imgs of soft tissue

  • bone scans - a nuclear imaging test tht produces 2D imgs of the bones

  

✦﹒cells that lose control results in cancer, which are unhealthy cells tht hv issues in cell division regulators in the cell cycle

• regulators in cell division include the following—

  • proto-oncogenes - normal genes which affect normal cell growth and poliferation; codes for pos cell cycle regulators

    • mutations in function cause oncogenes, which hv the potential to cause cancer

  • tumor suppressor genes - a segment of DNA that codes for neg. cell cycle regulators; inhibits/supresses cell proliferation + tumor growth

    • tumor supressor p53 works to shut down cell division when cell is stressed

• if cancer gets worse, it can metastasize, where cells penetrate into lymph nodes/blood vessels and spread to other areas of the body

• cell morphology helps identify if the tissue is cancerous or not

  • healthy characteristics - organized division + arrangement w/cell-cell junction, distinct features to perform specific function, same tissue, size, and shape, one small nucleus

  • cancerous - disorganized arrangement + uncontrollable division, lrg nuclei, vary in size + shape

  • note the different lvls of tissue changes in a biopsy sample:

    

✦﹒DNA microarrays allow scientists to look at thousands of genes and identify differences in gene expression, which is different in cancer cells vs healthy cells

• when a gene is expressed, the cell is turned on/active, producing mRNA of tht gene

  • mutations can turn off expression, inc expression (up regulation), and dec expression (down regulation)

  • if a cancerous cell’s expression on a gene different compared to a healthy cell’s, scientists would likely conduct a further study on that gene

• DNA microarray shows a fluorescent color tht indicates expression—

  • red - upregulated, w/inc expression of gene

  • green - downregulated, w/dec expression in cancer cells

  • yellow - equal gene expression of healthy + cancerous (which is good)

  • black/blank - no expression

  *brief steps of DNA microarray process frm edvotek in pltw

✦﹒a popular method tht calculates the similarities btwn gene expression profiles using the DNA microarray data is the Pearson [product-moment] correlation coefficient, which measures to cprrelation/relationship btwn two sets of data

scary ahh formula!!!

• x̄, ȳ - mean/average (add all values and divide it by amt of values)

• x_i, y_i - expression ratio in base 2 log form (the values at the data, i = each gene; gene 5 = x₅)

1. colors frm DNA microarray r converted to colors (ex: bright light intensity → 400, dull color → 100)

2. ratios of tumor (red) : healthy (green) r calculated and simplified (ex: 400:100 → 4:1 → 4/1 = 4)

   • up regulation - expression lvl > 1

   • down regulation - expression lvl < 1

     ^ this is not efficient, hence why values r converted to log₂

3. convert ratios to log₂

   • positive value - up regulated/induced by tumor formation

   • negative value - down regulated/suppressed by tumor formation

   • zero - equivalent expression in both cells (no affect)

4. use log ratio values and plug it into the pearson correlation coefficient equation

   • positive coefficient - similar gene expression profiles; lrger = stronger relationship

   • negative coefficient - gene expression profiles behave differently; farther frm 0 = stronger relationship

   • value of 1 - identical gene expression profiles

   • value of 0 - gene expression profiles behave in an unrelated manner

﹙✦﹚﹒know functions of 4 diagnostic imagings, cell morphology of healhy vs cancer , how dna microarrays work + especially analyzing them w/pearson coefficient

→ not mentioned : hierarchical clustering

﹙3.2 - Reducing Your Risk﹚

✦﹒certain risk factors increase the chances of developing cancer— these risk factors can be organized into three categories

• behavior risk factors - behaviors you can change (ex: smoking)

• environmental risk factors - toxins found in your surrounding environment tht can inc your cancer risk (ex: radon + asbestos)

• genetic risk factors - determined by genes + r inherited by parents (ex: sex, race + whether or not you’ve inherited the genes related to the disease)

✦﹒skin cancer is a common cancer in which its risks are preventable

• the sun emits energy in the form of ultraviolet (UV) photons tht can dmg the DNA in your cells and cause this cancer

  • occasionally, the dmg is repaired by special enzymes

  • more exposure = more repairing, increasing the risk

• sunscreen is a simple way to reduce the risk, either filtering or blocking UV rays frm touching your skin

• recall that a lab related to skin cancer was conducted utilizing yeast cells, a good model system as single-celled organisms tht r easy to grow + work much like mammalian cells

• recall from pbs the ABCDE self exam for melanoma— asymmetry, borders, color, diameter, evolving

• actinic keratosis (AK) lesions can form by exposure to UV + r precancerous skin cells, eventually leading to squamous cell carcinoma

  • a treatment for this is 5-fluorouracil (5-FU), which inhibits enzyme thymidate synthase in order to block the thymidine formation required for DNA synthesis + disrupts splicing of pre-mRNA by preventing post-transcriptional modification of tRNAs and assembly activity of protein complexes

    • 5-FU belongs to a family of pyrimidine antagonists, which are structurally similar to naturally occurring nucleotides, often being as false precursors in DNA/RNA or inhibition of proteins involved in nucleotide metabolism

✦﹒breast cancer is an example of a cancer that has genetic risk factors

• two genes associated w/inherited cases of breast cancer are breast cancer gene 1 + 2 (BRCA1 + BRCA2)

  • they normally function as tumor supressor genes, helping to repair DNA dmg + prevent cancer cell formation

  • in inherited cases, they r mutated

• preventative measures of this cancer include hormonal or antiestrogen therapy, prophylactic surgeries, nutrition, + physical activity

• cancers r divided to categories—

  • sporadic cancer - cancer occurring occasionally, singly, or in scattered instances

  • familial cancer - cancer that runs in families more often than chance; may be a sign of shared environmental or lifestyle factors

  • hereditary cancer - an inherited disorder gives hv a higher-than normal chance of developing the cancer, often b4 age 50

• marker analysis is a technique where the gene mutation is analyzed using a genetic marker instead of directly analyzing the gene itself

  • genetic markers r used as a short seq of DNA repeated many times called short tandem repeats (STRs, also microsatellites)

    • # of repeated sequences varies frm person to person, more = longer DNA fragment

    • alt forms of STR correspond to different alleles, often occurring in introns (noncoding regions of DNA)

  • marker analysis is based by gel electrophoresis results, in which a standard curve is constructed

    • to make one, the relative mobility value (R_f) is calculated and compared to fragment length

  

✦﹒precancerous cells can be caused by viruses

• human papilloma viruses (HPVs) - sexually transmitted infection tht causes abnormal cells to start growing, eventually becoming cancerous

  • main cause to cervical cancer, linked to mouth + throat cancer

• epstein-barr virus (EBV) - a type of herpes virus tht causes infectious mononucleosis (mono), infecting and staying in b lymphocytes

  • linked to hodgkin diseases + stomach cancer

  • inc risk of nasapharyngeal cancer + burkitt lymphoma

• hepatitus B + C virus (HBV, HCV) - both known to cause liver infection, where long term infection inc risk of liver cancer

• precancerous cells can be removed by cryosurgery, a procedure tht uses extreme cold produced by liquid nitrogen/argon gas to destroy the abnormal tissue

✦﹒routine cancer screenings help prevent and detect cancer early before developing; this includes the following—

• endoscopy - examines the lining at the esophagus, stomach, and small intestine, using an endoscope, flexible tube w/a camera at the end

  • endoscope is inserted into mouth all the way to the first part of the small intestine; helps show if there are any abnormalities/explains any occurring symptoms

• esophagogastroduodenoscopy (EGD) - examines the lining at the esophagus, stomach, and first part of small intestine (duodenum), using an endoscope

  • also called upper endoscopy, performed at a hospital or medical center

• colonoscopy - examines inner lining at the rectum and large intestine (colon) using a colonoscope (similar to endoscope)

  • screens for colon cancer, identify abnormal growths (polyps) + investigate intestinal symptoms

  • most colonoscopes hv retractable instruments to remove polyps

• mammography - a x-ray technique used for screening + diagnosis of breast cancer

  • screening helps detect breast tissue abnormalities

  • diagnostic helps investigate breast lumps/tissue changes

• transesophageal echocardiogram (TEE) - a ultrasound tht takes heart pics frm food tube tht runs beside the heart on the inside of the chest

  • ultrasound transducer (attached to endoscope) uses sound waves to take pics of heart’s motion + interior anatomy

  • helps diagnose issues w/blood flow, function + may also look for any blood clots at the heart

• all info comes from this biodigital—

  :: link

what routine cancer screening for breast cancer looks like (patient 1, sawyer lee)

﹙✦﹚﹒know the risk factors of cancer, categories of cancer, marker analysis and how to make a standard curve, and treatment of cancer, including the routine screenings and cryosurgery

→not included : types of skin cancers, routine screenings for colorectal, cervical, endometrical, lung, and prostate cancers

﹙3.3 - Treating Cancer﹚

✦﹒note the eight treatment types for cancer

• surgery - operation/procedure used to remove a tumor frm the body

  • best used when tumor is contained in one area

  • side effects include pain, infection, bleeding

• chemotherapy - a drug treatment tht uses powerful chemicals to kill fast growing cells in the body

  • lessens chances of cancer returning, stops/slows tumor growth

  • side effects include hair loss, fatigue, low blood cell counts

• radiation therapy - uses beams of intense energy to kill cancer cells by destroying their genetic material

  • used to treat cancer + ease symptoms, does the same as chemo

  • side effects include fatigue, hair loss, memory issues, headache

• immunotherapy - treatment tht takes advantage of body’s immune system to fight cancer cells

  • teaches immune system to recognize + destroy cancer cells OR supplements immune system w/proteins that boost pwr

  • side effects include flu like symptoms

• targeted therapy - a type of chemo tht prevents growth + spreading of cancer

  • drugs specifically target certain parts of cancer cells tht control how they grow, divide, and spread

  • side effects include fatigue, high blood pressure, issues w/blood clotting and wound healing

• hormone therapy - stops/slows growth of cancer cells + lessens chance of returns, eases symptoms

  • either blocks body’s ability of hormone production OR interfere w/how hormones behave in the body

  • side effects include vaginal/menstruation changes, not flashes, mood swings, fatigue

• stem cells transplant - restores blood forming stem cells in ppl who lost theirs frm treatment (ex: high chemo dose)

  • stem cells r added and travel to the bone marrow to produce new blood cells

  • either come frm patients own tht were removed prior to other treatments or donor cells

• precision medicine - an approach to disease treatment tht takes accountability of individual variability in genes, environment, and lifestyles

  • specific drugs r given based on patients response to the drug according to their genes

  • used for certain cancer to help know wht treatment works best

  • examples include immunotherapy and targeted therapy

✦﹒biofeedback therapy is a type of therapy that is designed to help patients to become attuned to the way in which the body reacts to stress and learn ways to use the mind to influence the many of the body’s involuntary functions

• in a biofeedback therapy session, the patient is hooked to various sensors, learning about how their body reacts to stress by looking at their changes in heart rate, blood pressure, or any other physiological indicators

• the goal is for the patient to positively affect their physical response to stress

✦﹒prosthetic is an artificial device that replaces or augment a missing or impaired part of the body

• a prosthetic arm is composed of the pylon, socket, suspension system, and control system

  • pylon makes up the frame/skeleton of the limb

  • socket connects the prosthesis to the end of the remaining limb; its the joint

  • suspension system secures the entire device + attaches the socket to the residual limb

  • control system provides electronic control

• myoelectric control is where the limb is controlled by listening to muscles remaining in the residual limb that the patient can still contract

  • electrodes placed on the surface of the skin can measure the muscle movements frm the small electrical signals tht the remaining muscles make

  • the signals frm the muscles r detected frm the electrodes and then used to control the prosthetic limb

• muscle reinnervation is where the limb is controlled by the brain as if the arm was never amputated in the first place

  • a surgical procedure is required for this, where amputated nerves r redirected to control a healthy muscle somewhere else in the body

  • keeping the amputated nerves allow its electrical activity to be sensed with electrodes and used to provide control signals to a prosthetic limb

✦﹒amputees undergo physical rehabilitation with the help of physical and occupational therapists

• physical therapists evaluate and records a patient’s progress to improve mobility while helping w/their treatment plan

  • first session includes assessment of wht the patient’s mobility and range of motion is at

  • typical physical therapy sessions include exercises tht r practiced to control the limb + assessment of the progress to figure out what can happen in the long run

• occupational therapists help people meet their mobility goals and achieve skills they need to live on a daily basis thru evaluation of what they have

  • typical occupational therapy session includes the therapist helping the patient to regain physical function and skills for everyday activities

  • phases of occupational therapy include periopaptive (recovery frm surgery), pre-prosthetic (treatment for any complications frm surgery), prosthetic training, and advanced training

• rehabilitation plans include—

  • unique physical needs (ex: mike would hv the goal to be able to be in marching band again)

  • a detailed outline of the plan for the next 6 months, including major milestones that need to be met along the way

  • any other biomedical science professionals who may be involved

    • therapist/psychiatrist may be involved to help emotionally and mentally recover and cope w/the amputation and use of prosthetic

    • prosthetists help create the prosthetic limb tht best fits the patient’s needs

﹙✦﹚﹒know the treatments for cancer, how prosthetic limbs work, + careers in cancer treatment

﹙3.4 - Building a Better Cancer Treatment﹚

✦﹒precision medicine is a field of medicine tht uses a person’s genetic profile, lifestyle + environmental factors to inform health care decision

• makes each person unique as their differences impact health and treatment differently than others

• treatment for late stage cancer is faster

• differences in our genes code for how people respond to drugs differently

• pharmacogenetics - the study of how genetic variation in coding influences how a person responds to medication; a combination of pharmacology + genetics

  • single nucleotide polymorphisms (SNPs) - a genomic variant at a single base position in the DNA

  • halotype - a set of DNA variants along a single chromosone tht tends to be inherited together; each person has 1 pair + is considered as their SNP profile

✦﹒nanomedicine is a area of biomedical research that seeks to use tools from the field of nanotechnology to improve health at a cellular and molecular scale to diagnose and treat disease

• a scanning electron microscope (SEM) is used to view nanoscale objects

✦﹒clinical trials are biomedical or health-related research studies that investigate how a new medicine or treatment works in human beings

• clinical trials have phases

  • phase I evaluates the safety of the drug, determines safe dosage range, identify side effects, and tests a small group of people (<100)

  • phase II sharpens the estimates of proper dosage, determines effectiveness, and researchers learn more abt the safety and side effects, testing a larger grp of people (up to 200)

  • phase III determines effectiveness + side effects, testing large grps of people (1k-3k)

  • phase IV collects additional info after the drug enters the market, including the risks, benefits, and optimal use

• clinical trials can be categorized to different types

  • controlled - one grp recieves treatment, another doesn’t

  • randomized - control grp and treatment grp r chosen at random

    • control groups are given a standard treatment or a placebo (an inactive pill, liquid, or powder tht has no treatment value) while treatment groups are given the new drug

  • double-blind - neither subjects nor scientists know who is assigned to which grp until after the data are collected

    • prevents subjects in different grps frm behaving in diff ways

    • prevents scientists frm introducing any unconscious bias into data collection process

    • single blind is where subjects don’t know their grp but researchers do, being prone to bias

  • open - where researchers + subjects know wht treatment is being given, often used to test surgical procedures + medical devices tht cannot be done w/blind or double blind

    • more prone to error + bias compared to double blind studies

  • factorial - used to test medicines in combination, but difficult to interpret results

    • first grp tests therapy A, second grp tests therapy B, third grp tests both therapies, and fourth grp tests none

  • crossover - used to test two treatments, participants gets both treatments

    • some r given drug A first and then drug B or vice versa

  • orphan drug - test drugs tht treat rare diseases (affects <200,000)

    • tested on small number of very sick ppl; if the drug works, improved health is usually readily apparent

• clinical trials must be approved + monitored by Institutional Review Board in US, designed to safeguard health of patients

• after the trial, data is submitted to Food and Drug Administration (FDA) for approval of marketing drug

  • FDA will survey side effects consumers experienced as it is marketed

﹙✦﹚﹒have an understanding of precision medicine, nanomedicine + clinical trials

→ not included : 3.4.4 Tiny Treatment bc its just a project

→nanomedicine is not tested much in EOC