Cancer Interventions, Screenings, Prosthetics, and Pharmacogenomics

Practice flashcards covering DNA microarrays, marker analysis, cancer screening schedules, stem cell transplants, immunotherapy types, biofeedback, prosthetics, biomechanical muscle rules, and pharmacogenomics.

What is a DNA microarray and how are cell samples prepared for it?

A DNA microarray is a glass chip used to see which genes are turned on or off in cancer cells compared to healthy cells. mRNA is collected, converted into stable cDNA, and tagged with glowing colors: healthy cDNA is tagged Green and cancer cDNA is tagged Red.

On a DNA microarray, what do red and green spots indicate?

A red spot indicates the gene is overexpressed (turned way up) in cancer, meaning the tumor is making too much of it. A green spot indicates the gene is turned off or down in cancer (and on in healthy cells), which often happens to tumor suppressor genes.

On a DNA microarray, what do yellow and black spots indicate?

A yellow spot indicates the gene is expressed equally in both healthy and cancer cells, with both red and green cDNA sticking perfectly. A black spot indicates the gene is totally inactive (turned off) in both types of cells.

What is Marker Analysis and what are Short Tandem Repeats (STRs)?

Marker Analysis is a test that examines genetic signposts located next to a bad gene instead of sequencing the entire gene. STRs are pieces of non-coding junk DNA that repeat the same sequence of letters over and over (such as GATA-GATA-GATA).

How does Marker Analysis show if a patient has inherited a mutated BRCA1 or BRCA2 gene?

Bad genes like mutated BRCA1 or BRCA2 are physically linked to an adjacent STR marker on the chromosome and almost never separate during reproduction. If a patient's DNA test reveals the exact same size STR marker band as a relative with breast cancer, they likely inherited the bad cancer gene along with it.

What are the routine screening guidelines and frequencies for breast cancer?

Women begin regular mammograms (X-rays of the breast) between ages 40 to 45, repeated every year or every 2 years.

What are the routine screening recommendations and starting ages for cervical cancer?

Screening starts at Age 21. For ages 21 to 29, a Pap smear is performed every 3 years. For ages 30 to 65, an HPV DNA test alone or a Cotest (Pap + HPV test) is performed every 5 years.

What are the routine screening recommendations and age thresholds for colorectal cancer?

Screening begins for everyone at Age 45. A colonoscopy is performed every 10 years if results are normal, or special stool tests can be performed every year.

What are the routine screening guidelines for prostate cancer?

Men discuss screening options with a doctor starting at Age 50. Testing uses a PSA blood test and a physical exam (DRE) conducted every 1 to 2 years.

What is the difference between an autologous and an allogeneic stem cell transplant?

In an autologous transplant, the patient uses their own stem cells which are collected, frozen, and returned after heavy chemotherapy, presenting no risk of rejection. In an allogeneic transplant, the patient receives stem cells from a matched donor such as a sibling or stranger.

What is Graft-versus-Host Disease (GVHD)?

GVHD is a dangerous complication that occurs only in allogeneic transplants when the donor's new immune cells (the 'graft') perceive the patient's normal organs (the 'host') as foreign enemies and attack the patient's skin, liver, and stomach.

How do checkpoint inhibitors function to treat cancer?

Cancer cells trick the immune system by engaging molecular brakes (such as PD-1) on T-cells to shut them down. Checkpoint inhibitors block these brakes, allowing T-cells to reactivate and attack the tumor.

What are monoclonal antibodies (mAbs) and how do they combat cancer cells?

Monoclonal antibodies are man-made proteins engineered to bind to a specific target on a cancer cell. They act like glowing flags instructing the immune system to destroy the cell, or they block essential growth signals.

How does CAR T-Cell Therapy work?

Doctors extract a patient's T-cells, genetically engineer them in a laboratory with a new receptor (CAR), expand their numbers, and infuse them back into the patient. This allows the T-cells to directly kill cancer cells without needing normal MHC protein presentation.

What is the functional difference between preventative and therapeutic cancer vaccines?

Preventative vaccines protect against cancer-causing viruses (such as the HPV vaccine), whereas therapeutic vaccines are administered to individuals who already have cancer to train their immune system to recognize and attack a specific tumor.

How do immune system modulators (cytokines) assist in cancer immunotherapy?

Cytokines, such as Interleukins and Interferons, are general signaling chemicals that act like a megaphone, sending a powerful signal that stimulates white blood cells to multiply and become aggressive.

In biofeedback therapy, what do electromyography (EMG) and skin temperature indicate?

EMG measures muscle tension, where high values indicate stress and low values indicate relaxation. Skin temperature indicates stress level through blood flow: stress causes vasoconstriction, leaving hands cold, whereas relaxation causes vasodilation, warming the fingers.

What physiological readings on EMG and skin temperature represent perfect relaxation in biofeedback?

Perfect relaxation is indicated when the EMG reading drops down and the skin temperature goes up.

What are the socket, pylon, and suspension system of a prosthetic limb?

The socket is the custom cup that hugs the residual limb and carries body weight; the pylon is the internal metal pipe or pole acting as the artificial bone or shin; and the suspension system consists of straps, locks, or suction that keep the limb attached to prevent pistoning.

What is prosthetic pistoning and why is it problematic?

Pistoning occurs when a poorly fitting suspension system allows the residual limb to slide up and down like a piston inside a tube, resulting in painful skin blisters and sores.

What distinguishes a myoelectric arm from neural interfacing?

A myoelectric arm uses surface EMG sensors inside the socket to detect muscle signals from the skin (e.g., flexing the bicep opens the prosthetic hand), whereas neural interfacing places wires directly into nerves or the brain to interpret thoughts directly without using muscle signals.

What are Rules 1, 2, and 3 of the biomechanical muscle rules?

Rule 1 states that muscles must cross at least one joint to cause movement. Rule 2 states that muscles only pull and never push, generating force by shortening. Rule 3 states that muscles have an Origin (attachment to a stationary bone) and an Insertion (attachment to a moving bone).

What are Rules 4 and 5 of the biomechanical muscle rules?

Rule 4 states that contracting muscles decrease joint angles during flexion and increase joint angles during extension. Rule 5 states that muscles operate in opposing (antagonistic) pairs because they cannot push, requiring one muscle to close a joint and another to reopen it.

What is a Single Nucleotide Polymorphism (SNP)?

A SNP is a single-letter variation in a DNA sequence between different individuals (such as carrying a T at a site where another person carries a C), representing the most common type of genetic variation.

What is pharmacogenomics and how does it enable personalized medicine?

Pharmacogenomics is the study of how an individual's unique genetic profile alters their response to medications. By analyzing SNP profiles that affect liver drug metabolism, doctors can predict drug efficacy, avoid toxicity, and personalize exact dosing for a patient's DNA.