3.2 Assessment Study Guide

How does gel electrophoresis with genetic markers work?

1. Extract DNA from the sample 2. Perform polymerase chain reaction (PCR) to amplify the BRCA genes. PCR uses specific primers designed to target the regions of interest within the BRCA genes. These primers will bind to the complementary DNA sequences and initiate DNA replication, resulting in the amplification of the target DNA fragments. 3. Prepare the gel. 4. Mix the PCR products with a loading buffer that contains a tracking dye to monitor the progress of gel electrophoresis. 5. Submerge the gel tray into an electrophoresis chamber filled with the same buffer used to make the gel. The negatively charged DNA fragments will migrate towards the positively charged electrode, with smaller fragments moving faster than the larger ones. 6. After electrophoresis, carefully remove the gel from the tray and stain it with a DNA-specific dye, like ethidium bromide or SYBR Safe. The dye binds to the DNA and makes it visible under UV light.

Importance of early detection of skin cancer

1. Increasing treatment success - increases the chances of successful outcomes 2. Enables less invasive treatment options, such as localized excision or topical therapies 3. Reduces the mortality rates as skin cancers that are identified early are typically smaller and less likely to have spread to other parts of the body

Design a research study to look at one of the activity/disease associations found on your Student Response Sheet. Include the following information in your study: who will participate and how you will determine if the risk factor actually increases or decreases the chance of developing the disease.

1. Participants will be recruited through advertisements in local communities. 2. Participants who meet the eligibility criteria will undergo an initial assessment which will include demographics, physical activity assessment, cardiovascular health assessment, and follow ups (regular health check-ups and medical records review). The data will be analyzed to determine the association between physical activity levels and the risk of developing cancer.

basal and squamous cell skin cancer

Basal cell skin cancer is the most common type of skin cancer that develops in the basal cells, which are found in the deepest layer of the epidermis, typically appearing as a slow-growing, flesh-colored or pinkish bump on the skin. Squamous cell skin cancer, on the other hand, arises from the squamous cells, which are flat cells in the outermost layer of the skin, and it often presents as a red, scaly, or crusted lesion that may bleed or ulcerate.

Why isn't cancer an epidemic?

Because although the cancer rates are rising so is the population. This trend is offset, however, by the number of new births, which is also increasing.

What can exposure to UV light cause?

Actinic keratosis (AK) lesions to form on the skin. They are small, scaly patches of precancerous skin cells on the epidermis (top layer of the skin). If untreated, they can turn into a form of skin cancer called squamous cell carcinoma. One treatment is a topical medication called 5-flurouracil.

Genetic marker

Alteration in DNA that may indicate an increased risk of developing a specific disease or disorder. A shot sequence of DNA associated with a particular gene or trait with a known location on a chromosome.

Where is skin cancer prevalent in?

Australia

What are ways to prevent skin cancer when facing ultraviolet radiation from sunlight?

Avoid going into strong, direct sunlight, wear protective clothing, and wear sunscreen lotions.

Familial cancers

BRCA 1 and 2: breast, ovarian and prostate

Why do doctors believe the cases of breast cancer in Judy's family are hereditary?

Because both males and females are affected, and because there are no cases of ovarian cancer. So there must be a mutation in the BRCA2 gene.

Why is Jennifer the best candidate for genetic testing?

Because she developed cancer at an early age so she is most likely to have a BRCA2 mutation.

Why are yeast cells a good model system to study the effects of UV exposure?

Because they are single-celled organisms that are easy to grow. Their DNA is organized and replicated in much the same was as mammalian DNA as they're eukaryotes.

Where is cervical cancer prevalent in?

Brazil

What is BRCA1 and BRCA2?

Breast cancer genes. If you have these genes you are more likely to have breast cancer later in life and the chances for ovarian and prostate cancer also increase. Just because you have active breast cancer does not mean you carry the gene though...but if you have the gene you are at a more increased risk of developing breast cancer.

Where is leukemia prevalent in?

Canada

What are chemicals and radiation that are capable of triggering the development of cancer called?

Carcinogens

What cancers can be caused by viruses that infect human cells?

Cervical cancer, liver cancer, and certain lymphomas, leukemias, and sarcomas.

Where is liver cancer prevalent in?

China

What kind of cancer relates to fat consumption?

Colon cancer. Limiting fat consumption and calorie intake appears to be one possible strategy to decrease risk for some cancers, because people who consume large amounts of meat, which is rich in fat, and large numbers of calories exhibit an increased cancer risk.

Melanoma

Deadliest form of skin cancer.

What can smoking cause?

Lung cancer, cancer of the mouth, larynx, esophagus, stomach, pancreas, kidney, and bladder

Lymphoma of the skin

Lymphoma of the skin, also known as cutaneous lymphoma, is a type of non-Hodgkin lymphoma that primarily affects the skin. It can manifest as various subtypes, including mycosis fungoides and Sézary syndrome, and typically presents with symptoms such as itchy, red, scaly patches or raised nodules on the skin. Cutaneous lymphoma may be confined to the skin or progress to involve lymph nodes and other organs over time.

What do X-rays emit?

Radioisotopes.

What should patients using 5-FU expect with treatment?

Rashes, dryness, itchiness, or burning.

How was 5-FU discovered?

Researchers Abraham Cantarow and Karl Paschkis found that liver cancer cells took up radioactive uracil much more easily than normal liver cells. Meanwhile, Charles Heidelberger was investigating how fluorine binds to proteins to stop them from working so he created uracil containing fluorine (5-FU).

What is the relative mobility value symbol and how is it calculated?

Rf = Distance the DNA fragment has migrated from the origin (gel well)/Distance from the origin (gel well) to the reference point (tracking dye)

What are the genetic markers used in marker analysis?

Short DNA sequences called short tandem repeats (STRs or microsatellites).

What is the most common type of cancer in the US?

Skin cancer

What is the greatest public health hazard?

Smoking

Stages of basal cell carcinoma in tissue

Stage 0: The cancerous cells are confined to the epidermis Stage 1: It has spread beyond the epidermis and may extend into the dermis. The tumor is less than 2cm thick Stage 3: The basal cell tumors are larger than 2cm thick, but have no spread to nearby organs or lymph nodes. Stage 4: Basal cell carcinoma may have spread into the bones of the face or into a nearby lymph node Stage 5: Basal cell carcinoma can be longer than 3cm thick and has metastasized (spread) to more than one lymph node. The tumor may also affect additional facial bones.

Given what you know about these two strains of yeast, what role does a cell's ability to repair DNA play in how well it tolerates exposure to sunlight?

Sunlight contains ultraviolet (UV) radiation, which can cause damage to the DNA within cells. Cells with efficient DNA repair mechanisms can detect and repair the UV-induced DNA damage, preventing the accumulation of mutations and potential harmful effects.

Where is lung cancer prevalent in?

The U.K.

Where is colon cancer prevalent in?

The U.S.

Marker analysis

is a genetic technique whereby the sequence of the gene is not directly analyzed, but the mutant copy (allele) of the gene is inferred through analysis of a genetic marker

What does familial mean?

transmitted in the gametes through generations

Self examination for melanoma

- Examine your body front and back in a full-length mirror - Look at underarms, forearms, and palms - Look at your legs, between toes, and soles of feet - Look at neck and scalp - Check back and buttocks THINGS TO LOOK FOR: - ABCDE: 1. Asymmetry - one side may be dark the other lighter 2. Border irregularity - Borders that are jagged or uneven 3. Color changes - Shades of tan, brown, or black, or white, red, or blue. 4. Diameter - About 1/4 of an inch (pencil eraser) or 6 mm 5. Evolving - Changes over time in moles

What are some preventative measures for breast cancer?

- Maintaining a healthy weight - Staying active - Eating a healthy diet - Hormonal therapy shrinks the cancer before surgery by blocking estrogen production in the body and blocking the effects of estrogen on breast cancer cells. - Prophylactic mastectomy is typically done when there are abnormal changes in certain genes that increase your lifetime risk of breast cancer, like BRCA1 or 2 mutations, strong family history, or abnormal changes to the breast tissue. This surgery involves removing one or both breasts.

How many of the more than 100 types of HPV can be passed from one person to another through sexual contact? How many are a major cause of cervical cancer?

30 types. Among these, there are 13 high-risk types recognized as the major cause of cervical cancer.

What does sporadic mean?

A disease that occurs infrequently and irregularly.

Why use a negative control when running gel electrophoresis? If a band shows up in this lane, what does it tell you about your PCR products?

A negative control is used in gel electrophoresis to determine if there is any contamination or non-specific amplification in the experiment. It serves as a baseline to compare against the experimental samples. If a band shoes up in the negative control lane, it indicates the presence of contamination or unintended amplification, suggesting that the PCR products may not be reliable or specific to the target DNA sequence.

The lifetime chance of developing breast cancer is greatly increased in someone who has inherited an altered BRCA1 or BRCA2 gene. What role does environmental risk play into whether or not this person actually develops breast cancer?

A person who has a mutation in the BRCA1 or BRCA2 including bad habits could make it a lot easier for them to develop breast cancer. A person who has a mutation in those genes will have an increased chance of getting breast cancer and even though environmental risks could raise the chance a person could get breast cancer by a certain percentage in a person without the mutation the increased mutation in a person with the mutation is really high. The environmental risk factors in a person without the mutation isn't as bad as a person with the mutation as the risk factors increase the chance of getting breast cancer but not as high as the person with the mutation.

What foods decrease cancer risk?

Fruits and vegetables. It's recommended that people eat five to nine servings each day.

What are people with the bacterium Helicobacter Pylori or H. pylori at risk for?

Increased risk for stomach cancer.

What happens with women who have multiple sexual partners?

Increased risk of cervical cancer.

What is 5-FU's mechanism of action?

It is an anti-metabolite, which is a category of chemotherapy drugs that work through disabling cell division once a cell incorporates it into its cellular metabolism. 5-FU works through mocking building blocks of DNA and RNA in order to stop their synthesis.

Where is stomach cancer prevalent in?

Japan

Which family members have the BRCA2 mutation?

Jennifer, Laura and Judy because they all have allele 3. Allele 3 is the allele that is linked to the BRCA2 mutation so since these three are the ones with allele 3 they have the mutation.

Kaposi Sarcoma

Kaposi sarcoma is a type of cancer that originates in the cells that line the blood vessels or lymphatic vessels. It is commonly associated with a viral infection called human herpesvirus 8 (HHV-8), particularly in individuals with weakened immune systems, such as those with HIV/AIDS. Kaposi sarcoma typically presents as reddish-purple or brownish skin lesions that can appear on the skin, mouth, lymph nodes, or internal organs. It can also cause symptoms like swelling, pain, or difficulty breathing depending on the affected areas.

Melanoma Skin Cancer

Melanoma is a type of skin cancer that develops from the pigment-producing cells called melanocytes, typically appearing as an abnormal mole or dark spot on the skin that may exhibit asymmetry, irregular borders, color variation, or changes in size or shape. Melanoma is considered the most dangerous form of skin cancer due to its tendency to metastasize or spread to other parts of the body if not detected and treated early.

Merkel Cell Skin Cancer

Merkel cell skin cancer is a rare and aggressive type of skin cancer that arises from the Merkel cells, which are responsible for sensory perception in the skin. It typically presents as a firm, painless nodule on the sun-exposed areas of the skin and is associated with factors such as advanced age, sun exposure, and a weakened immune system.

Does industrial pollution appear to be a major cause of most cancers in the population at large?

No, because the frequency of most human cancers has remained relatively constant over the past half-century.

How many cancer deaths is smoking responsible for?

One out of every three

How can two individuals have different sized bands and how they may be associated with different alleles (for BRCA).

People can have different sized bands due to the presence of different alleles. Mutations in the BRCA gene can result in the addition or deletion of nucleotides, leading to differences in the size of the DNA fragments.

What are lag times?

Period between exposure and onset of disease.

Which allele is associated with the BRCA2 mutation?

The allele which is associated with BRCA2 mutation is allele 3. Both Jennifer and Laura are known to have the BRCA2 mutation and have had breast cancer. Allele 3 is the only allele that the two patients share which means that it must be the one associated with the BRCA2 mutation.

What happens to people who both smoke and drink with cancer?

The cancer risk is more than 40 times greater than that of nonsmokers and nondrinkers.

What happens to construction workers who handle asbestos?

Their cancer rates are 10 times higher than normal, proving the dangers of carcinogens.

How do viruses trigger the development of cancer?

They enter living cells and cause the infected cell to produce more copies of the virus.

What happens to women who have an abnormal BRCA1 or BRCA2 gene by the age of 70?

They have a 50-80% risk of breast cancer

How do pyrimidine antagonists work?

They inhibit the synthesis of pyimidines to inhibit DNA/RNA synthesis so cell division can't occur.

What do carcinogens do?

They mutate and can cause cancer over a prolonged amount of time.

What does hereditary mean?

The passing of traits from parent to offspring

If yeast cells repair damage to their DNA in a similar manner to humans, what do these results tell you about the degree of DNA repair that occurs in our cells each time we expose ourselves to sunlight?

The results suggest that our cells also have mechanisms to repair DNA damage caused by sunlight exposure. The degree of DNA repair in our cells when exposed to sunlight is significant, as our cells have evolved DNA repair pathways to counteract the harmful effects of UV radiation. This repair process helps prevent the accumulation of mutations and maintains the integrity of our genetic material.

What happens to heavy smokers or heavy drinkers with cancer of the esophagus?

The risk of developing cancer of the esophagus is roughly 6 times greater than that for nonsmokers/nondrinkers.

Can prolonged or repeated exposure to certain types of radiation cause cancer?

Yes

Can a person's chances of developing cancer be influences by the inheritance of certain kinds of genetic alterations?

Yes. These alterations tend to increase an individual's susceptibility to developing cancer in the future. Ex.: About 5% of breast cancers are thought to be due to inheritance of particular forms of a breast cancer susceptibility gene.

What are people who develop AIDS after having HIV at risk for?

a cancer called Kaposi's sarcoma which is a malignant tumor of blood vessels located in the skin.

What is melanoma?

a serious form of skin cancer that is associated with excessive sun exposure. They are lethal tumors. But can be reduced by avoiding excessive exposure to the sun, using sunscreen lotions, and wearing protective clothing.

most common form of skin cancer

basal cell carcinoma

Hereditary cancers

cancers that run in a family line (90% of cancers are not hereditary)

You have been contracted to design a new medical intervention to help prevent skin cancer. What type of medical intervention would you design? Describe your medical intervention and explain how it works to prevent skin cancer.

one potential medical intervention to prevent skin cancer could be a topical application or sunscreen formulation that incorporates advanced DNA repair enzymes. These enzymes would be designed to specifically recognize and repair UV-induced DNA damage in the skin cells. The intervention would work by applying the sunscreen or topical formulation containing the DNA repair enzymes to the skin before sun exposure. As the skin is exposed to sunlight, the UV radiation would cause DNA damage. However, the DNA repair enzymes present in the formulation would recognize and repair the damaged DNA, preventing the accumulation of mutations and reducing the risk of skin cancer development. In addition to the DNA repair enzymes, the formulation could also include ingredients that provide broad-spectrum UV protection, such as physical or chemical UV filters, to further shield the skin from UV radiation.

Spontaneous cancers

requires two independent mutations

What are short tandem repeats?

sequences of DNA that repeat over and over again