Signs And Symptoms Of Lung Cancer Biology Essay

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Cancer is related to mutations in the cells that cause on controlled growth of these cells. Cancer of cells results in the formation of masses of cells called tumors, this is due to the increased and uncontrolled division of the cell.

So, lung cancer is a disease which affects our respiratory organ (lungs) resulting in uncontrolled growth and division of lung epithelial cells. Lung cancer can be very fatal since the cells that get infected with cancer, can't perform their respiratory function. Also lung cancer tends to be metastatic which means that it tends to spread and carry cancer from the lungs to other body organs.

Lung cancer can arise in any part of the lung but, 90% to 95% of the cases arise from cancer infecting the epithelial cells of the lungs. Lung cancer can infect the cells lining the bronchial airways in this case it is called bronchogenic cancer. Also cancer can infect the pleura which are a layer of cells lining the lungs and the chest wall and in this case it is called mesotheliomas cancer.

It is still not clear who is the first scientist that discovered lung cancer but, there is evidence that people noticed this disease hundreds of years ago and it was then considered as a very rare disease.


Signs and symptoms of lung cancer:

Signs and symptoms differ from one lung cancer patient to another. Signs and symptoms depend on where the tumor is and what is its size wither small or big. The patient can either experience some symptoms or no symptoms at all.

In case of no symptoms:

Lung cancer is discovered during usual or routine checkup either by a CT-scan or a X-ray of the chest where a small mass of cells appears on the x-ray or CT-scan indicating lung cancer. The numbers of cases discovered by this technique are usually 25% of lung cancer patients.

In case of symptoms appearance:

After cells become exposed to cancer and start uncontrolled division, many of the following symptoms start to take place:

Difficulty in taking breath and wheezing.

Chest pain.

Hemoptysis where coughing is accompanied by blood.

Also if cancer affects nearby nerve cells, it can cause pair in the shoulder and in some cases paralysis.


What causes lung cancer?

Smoking is the most common cause of lung cancer, it causes lung cancer because there are certain substances that are found within the tobacco that cause the cancer.

These substances are called carcinogens (meaning cancer causing agents) that are the reason for the damage of the lung cells and when a cell is damaged it may become cancerous over a period of time. Although its quite difficult to predict the chances of a smoker developing lung cancer, but the chances depend on some factors like: how long this person have smoked, the age that person began smoking, and how many cigarettes a day that person smokes.

Other than smoking, there are other causes of lung cancer that include:

1- The exposure to carcinogens through one's job, like exposure to asbestos

in the mining or construction industries. When asbestos particles are

inhaled hey remain in the lungs damaging its cells. Other harmful

substances are like arsenic, coal products and nickel chromate.

2-Exposure to radiation either through one's job or for medical reasons like


3-The presence of Radon gas (which occurs naturally in soil and rocks) is

considered harmful and may cause in lung cancer development

4- Air pollution

5-Having a previous lung disease

6-A family history in lung cancer

7- Diet and lowered immunity

Mechanism of lung cancer:

1-Ras oncogenes mutations are often present in human cancers as they are responsible for the formation and development of the disease. In more than one quarter of the lung adenocarcinoma patients Ras mutations are present. NF-?B which is a vital controller of cell survival and an essential mediator of tumor progression is activated by Ras mutations and is aided by the atypical PKCs and their adapter p62. however it has been showed in some researches that the effect of the NF-?B is still indeterminate affected by the target organ and the presence of inflammation. However preliminary studies showed that Ras results mostly in adenomas and adenocarcinomas in the presence of the p62. Ras transformations in the absence of p62 were ruined as Ras transformation results in p62 proteins accumulation.

2- Aurora kinase A is a molecule that is present in cells and has numerous tasks in mitosis such as activation of centrosome, microtubule dynamics, spindle assembly checkpoint, chromosome segregation, and cytokinesis.

Surprisingly, it was found that in more than half of the lung cancer patients Aurora kinase A was highly expressed which lead to its oncogenic effect. Moreover polyploidization, centrosome amplification, and chromosomal instability which aid in the development of cancer may be resulted from overexpression of the Aurora kinase A . High expression of Aurora kinase A also may result in cells that are taxol-induced apoptosis.


Many ways of identification of lung cancer are present:

Imaging studies: X-rays, ultrasound, CAT (computerised axial tomography) scans, MRIs (magnetic resonance imaging), PET (positron emission tomography) scans and bone scans.

Sputum tests

Diagnosis of sputum samples for the presence of cancerous cells

Blood tests:

Tissue damage can be tested by the baseline blood tests which include renal and liver function tests, calcium and lactate dehydrogenase levels.


A sample of the lung tissue is taken and analyzed for the presence of cancerous cells. More tests are carried if the tissues contain cancerous cells to have further diagnosis. The most common biopsy techniques are: bronchoscopy and thoracocentesis and these analysis methods may also detect the cancer stage.


To prevent lung cancer, there are some risk factors that need to be avoided or stopped. Also some protective factors should be increased.

The risk factors that should be avoided include:

Cigarette and pipe smoking are two of the most dangerous risk factors that can greatly cause lung cancer. Also secondhand smoking should be avoided because the smoke entering the lungs can initiate lung cancer.

As for environmental risk factors, exposure to radon can lead to lung cancer. Radon is a radioactive element that can be present in a gaseous state and can pass through cracks and holes and reach homes leading to lung cancer and death. 30% of non smokers diagnosed with lung cancer are usually linked to radon exposure.

Air pollution

Alcohol consumption in large amounts have showed to cause lung cancer in many cases

The protective factors that should be increased include:

Eating vegetables a lot have showed to decrease the risk of getting lung cancer.

Exercise makes physically active people to be highly unlikely to get infected with lung cancer even if they smoke, in contrast to physically inactive people which showed high risk to have lung cancer.


When treating lung cancer, it should be first taken into consideration whether SCLC or NSCLC is present, the stage the tumor has reached, and a person's overall general physical condition. The most common methods to treat lung cancer are: surgery, chemotherapy and radio therapy. They can be used all together or each one on its own.

The factors that are taken into consideration when choosing the type of treatment needed are:

1)The general health of the patient

2) The stage the Cancer has reached to

3) Where the cancer is within the lung

4) The type of lung cancer the patient has

5) Results of scans and blood tests

If the patient has small cell lung cancer its mostly treated with chemotherapy because the surgery wouldn't be useful at such a stage where the cancer has already spread by the time it was diagnosed. But if the patient has non-small cell lung then the cancer can be treated with chemotherapy, surgery, radiotherapy or any combination of these.

Treatment by stage for small cell lung cancer

if a patient has an early stage of small cell lung cancer, they are most likely to be treated by chemotherapy and radiotherapy to the lung. Its common for this type to spread to the patients brain and this is why doctors usually recommend that patients with small cell lung cancer to be treated with radiotherapy on the brain too in order to kill any cancer cells that may have spread but might be too small to be seen on scans.

If another patient has small cell lung cancer too but it didn't spread onto the lymph nodes in the centre if the chest then this case can be treated by surgery in order to remove the portion of the lung containing the tumor. But if the small cell cancer has already spread to the lymph nodes or to other body parts then the Chemotherapy and radiotherapy treatments will be given in order to relieve the symptoms and to help shrink the lung tumor down.

Treatment by stage for non-small cell lung cancer:

Stage 1.

This stage is uncommon but usually the treatment for it is surgery by removing the part of lung containing the tumor and if that's not possible then the patient is treated with radiotherapy try to cure the cancer

Stage 2.

Depending on the position of the tumor its either treated by surgery and then by chemotherapy to avoid it coming back or by radiotherapy if the surgery is not possible due to health reasons.

Stage 3.

By this stage the surgery may be done as a way of treatment but tit will be by removal of the lung and that will only happen when the tumor is far from the heart and safe enough t operate the surgery there, if not then the patient is treated with chemo and radiotherapy.

Stage 4.

During this stage the aim of the treatment is to control the cancer long enough to be able to make it shrink in order to reduce the symptoms. the treatment is by chemotherapy and biological therapies that help reduce the symptoms aiming for the patient to live longer.



Lung cancer is a disease caused by the uncontrolled cell division in epithelial cells of the lungs. It can be metastatic and can transfere cancer to other parts of the body. Cancer can infect different cells of the lungs as well as the bronchial pathways and in some rare cases it infects neurons.

Symptoms and signs vary according to how big is the tumor and where it is. Some patients may not experience symptoms and the lung cancer is detected by x-ray and ct-scan. In other patients where symptoms appear, there is heavy coughing accompanied with blood also heavy breathing and wheezing occurs.

There are many causes of lung cancer, for example heavy smoking causes lung cancer also air pollution, consumption of alcohol in large amounts and finally radon gas which is a radioactive element that can cause lung cancer and exposure to x-rays.

Diagnosis of lung cancer requires many blood tests as well as biopsy to search for the cells that have cancer inside the cell. Also the mechanism by which lung cancer takes place had two different pathways one is caused by ras oncogens and the other is Aurora kinase A.

To prevent lung cancer, smoking must be stopped as well as secondhand smoking because they greatly affect the lung also exposure to radon should be avoided.exercise should be increased as well as eating vegetables since they protect the body from lung cancer.

Role of each participant:

Shady wasfy: what is lung cancer?

Signs and symptoms


Matthews magdy: mechanism of lung cancer


Veronica ashraf : treatment.

Causes of lung cancer.