# Lung cancer

| Lung cancer |
| --- |
| Other names | Lung carcinoma |
|  |
| A chest X-ray showing a tumor in the lung (marked by arrow) |
| Medical specialty | Oncology, pulmonology |
| Symptoms | Coughing (including coughing up blood), shortness of breath, chest pain |
| Usual onset | After age 40; 70 years on average |
| Types | Small-cell lung carcinoma (SCLC), non-small-cell lung carcinoma (NSCLC) |
| Risk factors | * Tobacco smoking
* Air pollution
* Asbestos
* Radon
* Other environmental mutagens
 |
| Diagnostic method | Medical imaging, tissue biopsy |
| Prevention | Avoid smoking and other environmental mutagens |
| Treatment | Surgery, chemotherapy, radiotherapy, molecular therapies, immune checkpoint inhibitors |
| Prognosis | Five-year survival rate: 10 to 20% (most countries) |
| Frequency | 2.2 million (2020) |
| Deaths | 1.8 million (2020)

| Lung cancer |
| --- |
| *Classification and external resources* |
| ICD-10 | C33.-C34. |
| ICD-9 | 162 |
| DiseasesDB | 7616 |
| MedlinePlus | 007194 |
| eMedicine | med/1333 med/1336 emerg/335 radio/807 radio/405 radio/406 |
| MeSH | D002283 |

 |

**Lung cancer**, also known as **lung carcinoma**, is the uncontrollable growth of abnormal cells in one or both of the lungs. Lung cancer is more common in the right lung. Cigarettes are the leading cause. It kills 1.8 million people each year, more than any other cancer. Lung cancer has a 80-90% death rate, and is the leading cause of cancer death in men, and the second leading cause of cancer death in women. Only 5% cured.

It is often caused by external smoke going into the lungs. Tobacco smoking, cigarettes, cigars, or tobacco causes smoke to go in the lungs, which is unhealthy. Some smoke contains carcinogens.

## Cancer

Because lots of cancer is made in the body at random times every day, the body has to protect itself from the spread of cancers i.e. at the DNA level. For example, DNA demethylation and other manipulations of the DNA (such as post DNA being different or modified), for example how the post-DNA is post (after) transcription. Changing can involve methylation or demethylation of the DNA as one modification. The body does this all from scratch. The body tries to do it automatically with lots of redundancy so that people do not have to protect themselves.

At the level of enzymes, some cancers can be fought (by using drugs) by inhibiting them, or making them over-express, which may also be how some cancers develop in the body. RTK is over-expressed (or called over-active) in many human cancers for example. The target for these drugs which are used to treat the disease target these cells in order for the medication to do its job. They would be stored inside pockets in the enzyme and from there carry out their function in the body. Some example enzymes are RTK (Receptor Tyrosine Kinase) and TKI (tyrosine kinase inhibitor) drugs usually aim to inhibit these. Tyrosine is one example receptor, but there are more. There are many drugs which try to target (to inhibit or boost) receptors.

### Lysine

The DNA that is affected is often the Lysine-based strands in epi-transcriptomic (changes to RNA, which is before it turns into DNA), and post-transcriptional lines of defense. The parts that are lysine (K) within the helix, specifically when it is in the same region as histone (H) in the part of the DNA genome. Changes in this DNA are becoming more interesting to scientists who want to understand the body and they have had a lot of new implications in disease including of cancer. The body uses its own -methyltransferase, -methylase forms (and other forms) of H and K transcripts of DNA and this is thought to be one way the body protects itself against cancer. It makes its own DNA from scratch and starts the demethylation at the beginning of the transcript by methyltransferases such as DNMT3A/B and maintained by DNMT1.

It is done (for example) by changing the output of the DNA from its transcribing instructions. One example of a tumor-repressive mechanism (a way the body prevents cancer spread) is by demethylation in the body of the H3 Lysine 4 (H3K4) or alternatively one that is methylated being histone H3 Lysine 9 (H3K9), as examples. The way this affects the body is likely due to an immune system reaction of either the host of the cell (the person) or the cancer and its ability to spread or form drug resistances. The body also has checks on the cellular level for both lung cancer and broadly around the body to check for mistakes. Outside of the body, drugs and treatment options for cancer (such as radiotherapy) can for example can use enzymes in the body, and these aim to make the enzymes either work harder or less, or have more receptors (to be over-expressed) to fight the disease on that level.

## Types of lung cancer

There are two main types, the small cell lung cancer and non-small cell lung cancer (NSCLC). Small cell lung cancer seems to (typically) respond to chemotherapy and radiotherapy, and non-small cell lung cancer is more commonly treated with surgical removal of the lung tumor, but a treatment has seen mixed results or is controversial based on different opinions.

### Non-small cell lung cancer (NSCLC)

Non-small cell lung cancer (NSCLC) account for about 85% to 90% of lung cancer cases. People who have a deficient low pigment count have a higher chance of contracting lung cancer. There are three types of non-small cell lung cancer:

* Squamous cell (epidermoid) carcinoma
* Adenocarcinoma
* Large cell (undifferentiated) carcinoma

Symptoms:

* Chest pain
* Coughing
* Congestion
* Heartburn

## Cause

The large majority of people who get lung cancer have smoked for many years but other things cause lung cancer. There are types of lung cancers that appear in otherwise healthy patients who have never smoked.
Differences between people, and deficiencies, such as having a low pigment count, increase the risk for certain kinds (types) of lung cancer.

Other causes include asbestos, chromium, arsenic, iron oxides (oxides of iron), and radiation as radon gas. Radon is a tasteless, odorless (means you can not smell or taste it) gas. It is called the basement gas because it sinks to the bottom of the house and causes symptoms for people in the house basement or when they go to the basement.

## Prevention

Prevention (prophylaxis) usually includes quitting smoking (smoking cessation) for people that are already smokers. Other healthy habits might help prevent lung cancer, such as regular unpolluted (free from air pollution) fresh air and exercise, such as running. Avoiding regular exposure to carcinogens (i.e. occupational safety and health near metals and ore, and minerals, and secondly the cessation of smoking are preventative.

## Gallery

The white mass in the lung on left is a bronchogenic carcinoma, the leading cause of cancer deaths in both men and women in industrialized nations.Lung cancer in the left bronchus as seen with a bronchoscope.Three-dimensional (3D) CT image, shows a tumor in the left lung.