Genetically Inherited Cancer And Sources Biology Essay

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Cancer is an abnormal functioning of a cell that causes a large growth called a tumour. This abnormality is usually caused by a gene mutation, where there is more than half a dozen gene faults that cause this mutation. These mutations can be inherited or can develop over a life time. Inheriting a cancer gene will not ensure the development of cancer but rather that you are one step closer to developing cancer. By inheriting genes from two people this limits the chances of inheriting cancer to a 1 in 2 chance but this depends on how close the relative carrying cancer genes is. Benign tumours are non cancerous and can be removed easily while malignant tumours are fast grown cancerous tumours that spread easily and is a lot harder and more painful to remove. Malignant tumours can be locally invasive, meaning they affect surrounding 'normal' tissue, or metastatic which is when cancer cells are sent into other tissue away from the origin.

Explanation in own words

Cancer can develop from inherited genes as well as a genetic mutation in your own life time. The mutations of genes cause an abnormal functioning of cells. This usually occurs during mitosis and this begins the spreading of cancer cells until they form a tumour. Benign tumours are enclosed in a membrane preventing the faulty cells from spreading. If theses cells break free from the membrane they become a malignant tumours which spreads through the tissue and body. Cancer Genes that are inherited creates a higher chance of cancer development but there needs to be at least 6 mutations before cancer to begin.

Examples

A gene known as BRCA1 is a gene that repairs DNA. This gene is also inherited and increases the chance of breast cancer developing.

The gene, CDKN2A, gives a person a 70% chance of cancer if this gene mutates. Pancreatic cancer can occur and the intensity can differ depending on the victim's location for example the US has a alarming number of people with this cancer while America has a low number of people suffering from pancreatic cancer.

Diagram showing the circulation of bone cancer cells, http://topnews.com

Bone cancer- a genetically inherited cancer

Short description

Bone cancer can be caused by many factors; this includes inherited faulty genes and mutated genes. Leukaemia for example is a bone marrow diseases caused by faulty stems cells that produce an abnormal amount of white blood cells. Li-Fraumeni syndrome increases the chance of the development of a primary cancerous tumour in the bones. 95% of primary tumours developing in the bone are due to a wrong translation between the 11 and the 12 chromosomes.

Statistics

In the United States in the year of 2010 there were a total of 2650 new cases of bone cancer and a total of 1460 deaths. It was discovered that in the US osteoscarcoma( 400 new cases a year) and chondroscarcoma are the two most common forms of bone cancer. They are usually found to develop between the ages of 10 to 30.

Source: http://www.cancercare.com

Chances

Past treatments is one of the factors contributing to the development of genetically inherited cancers, for example if the patient has received chemotherapy treatment in the past this increases the chances of developing bone cancer as the genetic make-up of the cells can be changed from intense chemotherapy.

Why this cancer occurs?

Bone cancer is caused because of a faulty gene that is either inherited or mutates in the life time. When there are at least six gene mutations a cancer cell is formed that divides through the process of mitosis until a tumour is formed because the wrong proteins are produced. Benign tumours occur more frequently in the bones than malignant. They can be primary or secondary but do not spread and therefore can be left untreated without harming the carrier or they can be surgically removed. The development of primary malignant tumours within the bone is less than 1%, meaning that it is very rare to find the development of a malignant tumour within the bone but rather there is a higher rate of developing a secondary tumour that originated in another part of the body and spread into the bones.

How cancer is inherited

Scientist have identified the rare development of a primary malignant tumour in the bone is caused by genetic associations such as inheriting faulty genes. Genes are passed on by both parents and therefore there is a 50% chance of inheriting a cancerous gene. This also applies if a sibling or parent develops cancer as there is that chance that you inherited the same gene and therefore genetic testing is recommended. Genes are passed in humans in the following way:

Parental cells split by the process of meiosis which decreases the chromosome number from 46 to 23

The male gamete fertilises the female gamete creating a new cell with 46 chromosomes

This new cell begins the process of mitosis and forms a human

Chromosomes carry genes and therefore the offspring will have both his fathers and mothers genetic make-up

If both parents pass on the mutated genes, the mutation will become dominant but with most cases it is found that there is about six mutations that started the cancer development.

Genotypes:

An example of how mutated genes can be crossed: Punnet Diagram

Allele for normal function bone marrow cell- N

Allele for mutated bone marrow cell- n

N n

NN

Nn

Nn

nn N

n

Therefore, There is a 25% chance the offspring will have the mutated gene, 50% chance of carrying the gene and 75% chance of having a normal functioning cell.

Description of disease

Symptoms

In most cases the symptoms of bone cancer are not checked out and usually related to other sources. The main symptom is the development of pain in the bone that increase over time but is usually related to an exercise injury. Other symptoms include swelling around the area, development of lumps, respiratory infections, weakness in bones that lead to fractures and increased vomiting. Bone cancer can be identified through a few procedures like a CT scan or MRI, Surgery, staging which identifies how far the cancer has developed or a biopsy where a small sample of the bone is taken and tested in a lab.

Side effects/ complications

Due to the weakening in the bone there is an increased chance of fracturing the bones with falling or bumping the bone. There is also an increased chance that the cancer can become metastasis and spread to other parts of the body.

Survival

With the development of new treatments the chances of surviving has increased. The stage of the cancer contributes to the survival rates as the stages increase it makes it more complicated to treat and kill all cancer cells.

Stage 1- this stage is low grade cancer and has not spread into other parts of the body. This stage is divided into 1A, cancer is still within bone and 1B, cancer has developed in bone cavity and through the bone walls.

Stage 2- This is the high grade stage which like the first stage has not spread into other organs and is split into 2A, cancer is still within bone and 2B, cancer has developed in bone cavity and through the bone walls.

Stage 3- This is the stage where the cancer has spread to other parts of the body and can be either high grade or low grade.

This picture shows the different stages of the development of cancer, http://mahalo.com

Cancer treatments in past:

Chemotherapy

Chemotherapy is the use of drugs and medication to treat cancer. Theses drugs flow in the blood stream and kill any cancer cells as well as normal healthy cells, producing many side affects. The extent of the cancer determines the doses as well as the times the drugs must be taken e.g. weekly, daily. The side affects have been reduced and controlled over the years but this treatment previously caused a lot of pain and suffering. This included nausea, lose of appetite, vomiting, tingling sensation, numbness, anaemia, infection, diarrhoea, hair loss and mouth sores. Problems also occurred when trying to treat the side affects. Some had the extra expense of a dieticians or dentists to try keep up a healthy diet and fix the damage caused in their mouths by the extensive vomiting.

Surgery

Surgery is used to combat cancer in the following ways:

Surgical biopsies is a surgical process to confirm a diagnosis for example to confirm that a patient has lung cancer.

Staging is a term given to a surgical procedure that determines the extent of the cancer.

Another procedure is used to remove any obstructions that cause pain to the patient.

Surgery can be used to cut out cancer tumours or cells but this procedure is not completely reliable as cells divide too quickly and often some cancer cell are not removed and left to multiple.

Unfortunately the methods above left many people with no hope to have a chance to fight cancer. Transplants where unavailable back then due to a lack of knowledge, research and technology, unlike today where we have gained so much insight into stem cells and genetically inherited diseases.

Progress treatments to fight cancer:

Treatment

Advantages

Disadvantages

Stem cells

After a period of time of chemotherapy, a cancer patient will enter a procedure of introducing stem cells into the desired area that replicate quickly and take over the cancer cells. The cells can either be from the patient (Autologus transplant) or from a matching donor ( allogeneic transplant)

This process can cure many types of cancers as it uses healthy growth/ stem cells to replace the cells killed from the chemotherapy.

With the allogeneic transplant the battle for cancer does not end after the chemotherapy but an almost new immune system is created that fights cancer cells.

With Bone cancers only the allogeneic transplants can be used which decreases the risk of using cancer cells from donor.

Long process, the procedure may take weeks or months and requires a lot of time away from home for the patient as well as a drain in energy. The donation procedure is also long taking about a day with several injections lasting up to 5 minutes.

There is a high risk of tissue rejection with the allogeneic transplant. For cancers within the bone autologus procedures cannot be used as the risk of accidentally use of cancer stem cells is too high

Bone marrow transplant

This procedure is the actually procedure of transplanting the stem cells into the patient. The stem cells can then fight the cancer and replace the damage caused by the chemotherapy.

The chance of survival is very high as new stem cells within the bone marrow are found which creates an almost new immune system that can fight cancer in other parts of the body through the blood stream.

There is a high chance of finding a matching donor, 1 in every three patients finds a matching sibling while two thirds of patients find matching donors through the 7 million registered donors.

There is a risk of rejection of the new tissue. This can cause the immune system to see the new tissue as a threat and attempt to kill it.

Targeted therapy

Specific genes that contribute to cancer development can be isolated and treated with the use of another procedure. There is however a lack of research but there is much hope for this treatment in the future.

Targeted genes and proteins that contribute to cancer development can be treated with the combination of this therapy and another treatment like chemotherapy.

While the treatment uses chemotherapy the side affects are not as serious but include naueas, vomiting, muscle cramps and heart pains.

Chemotherapy

This treatment uses drugs to kill cancer cells. Unfortunately normal functional cells are also killed in the process producing many side affects.

This treatment is affective and does kill cancer cells.

Chemotherapy produces many side affects depending on the dosage. It also causes emotional drainage and physiological damage.

Moral dilemmas of treating genetically inherited cancers

The problem with genetically inherited diseases is it can be passed on to future generations. Genetic variation has a huge contribution to a recessive gene becoming dominant like inheriting the genes that increase the chance of the development of cancer. Both parents will have to be carrying the gene in order for it to become dominant. The offspring of two parents that have the recessive gene have a 50% chance of inheriting that gene. Alleles allow the gene to not be noticed in the first generation and therefore it can be a surprise when a family member develops cancer when no other immediate family member develops cancer. The general public believes that your genetic make up is a mix of the two parents and this prevents them from understanding the chances of inheriting recessive genes.

Diagram showing the development of cancer in the humerus, http://can-cer.net

Ethically there is a lack of understanding of genetics as well as cancer treatments that include stem cells. There are two types of stem cell transplants, embryonic and bone marrow stem cells transplant. The ethical issue is with regards to the embryonic transplant as human embryos are used and for this reason many clinics refuse to offer this transplant. For those patients receiving this treatment they can face discrimination as well as an emotional disadvantage if they are against this types of treatment themselves but this is their last resort. There is also an issue with regards to the research of theses treatments as there would have had to have been some form of testing which is usually on animals. There is a fear of what might occur in the future if we continue to interfere with the genetic make up of people. With these changes we are not sure of how stable the future generations will be as this contributes to the limitations on genetic variation. This includes our resistance to diseases as well as the mutations that can occur unexpectedly.

The patients receiving the treatment can be discriminated in society due to their choice of treatment. Chemotherapy leaves the patients with no hair on their heads and eyebrows which is hard to hide for example when you see a bald lady you assume that this is due to heavy chemo treatments for cancer. This leaves many cancer people feeling separated from society. They spend months in hospital and are left out on the latest news, styles and lives of their communities, countries and the rest of the world. This can leave them with poor social skills as they find it hard to relate to people. It is important that there is a strong support system for these patients.

They become emotionally drained and depressed due to the long periods of time spent in hospital, the dependence on medicine and the intensity of the side affects.

So from my personally view people who have genetically inherited cancers need to be told of the dilemma. That way they can prepare themselves and build up a strong support system.

Therefore I do believe it is important to tell the patients their chances of survival. That way they can prepare themselves, including their friends and family. It gives them valuable time to spend together and not be visiting in hospitals and seeing their loved one go through painful treatments like chemotherapy.

Personal view

I believe that there is very little hope for those who have genetically inherited cancers.

Stem cell treatments

Diagram showing part of the process of an autologus transplant, http://hubpages.com'

Stem cell transplants are probably one of the best treatments available for cancer victims. This treatment is so effective due to the ability of the stem cells, which replace the cancer and normal cells after the chemo, to grow and continue to fight any cancer cells that the chemo did not kill. It does this by creating an almost new immune system but this only happens with an allogeneic transplant. Autologus transplants have a high risk of accidentally using cancer stem cells to replace the cells killed by the chemo. With this transplant a new immune system is not created but it still is effective and kills cancer, in most cases. There are a lot of positives to these transplants but this is only the beginning. There is still more to be researched and developed. When dealing with genetically inherited cancers the genes mutations that caused the development of cancer do not disappear when new stem cells are inserted. While the cancer infected area might be removed the genes can still code for the mutation to grow again. There is such a high chance that the caner will develop once again. All it takes is for one cancer cell to be left over and start dividing.

Emotional Break down

Cancer has the ability to degrade a person to having no hope left in them or even a desire to fight to live. Chemotherapy is a harsh treatment that causes excessive vomiting, pain and many other side effects. The patients are left feeling weak and emotionally drained. Some patients refuse to continue with the treatment and would rather be left dead. When there s a genetically inherited cancer gene, if this gene is not deprived of functioning it creates high possibilities of the cancer redeveloping over and over again. For those patients that don't have a strong stable support system they will be open to feeling more depressed and alone as there is few people motivating the patient to continue fighting the cancer.

Influences on point of view

Sources

When I looked up genetically inherited cancer I found out that the inherited genes only count as one malfunction and that in most cases there needs to be at least six of these for cancer to develop. Therefore I do understand that if you inherit faulty cancer genes it does not mean you will develop cancer but rather you have an increased chance. When I thought about it and looked further I saw there is not much that can be done to get rid of those genes. Targeted gene therapy only stops the gene from functioning and still uses intense chemotherapy which is a painful treatment.

Experience with cancer

My grand father developed cancer when I was young and I saw how painful it was, not only to him but everyone that loved him. I watched how the stages worsened and how tired he was until he eventually past. His wife, my grandmother, had passed away from cancer a few years before and left so many people with scars and heavy hearts. At least when my grandfather developed the disease his friends and family were more prepared and ready for the worst to happen.

Knowledge from biology classes

I have recently learnt about genetics in biology and understand how genes are passed on. I know how genetic variation depends on many biological processes and there is a 50% chance of inheriting your mothers or fathers genes. I also have learnt about stem cells and how they are the growth tissue in the body.

Ethical issues discussed by media

I have researched the ethical views of some treatments and found the lack of understanding within the public. This is concerning as this implies that these treatments are not been widely advertised for cancer victims. These treatments can save their lives and therefore everyone needs to be educated about them. An example relating to stem cells is the belief that all treatments use human embryos and this unethical act can prevent a patient from researching this treatment that could save their life.

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