Small cell lung cancer (SCLC) is the fastest-growing type of lung cancer and shows higher metastasis when compared with other types of lung cancer. It is also the most aggressive form of lung cancer. Its mechanism is initiated within the breathing tubes known as bronchi located in the central region of the chest. As the cancer cells are small, they can increase and form large tumours within the lungs. In the meantime, these tumours can spread rapidly, showing metastasis to different body parts involving the brain, liver and bone.
Figure 1: Medical illustration of small cell lung cancer
Small cell lung cancer evolves the development of cancer cells within the tissues of the lungs. The lungs are the pair of cone-shaped breathing organs located in the chest. It is responsible for carrying out oxygen in the body while breathing in and taking out carbon dioxide while breathing out. Every part of the lungs consists of lobes. The left lung consists of two lobes, and the right lung, which is slightly larger, consists of three lobes. Pleura is the thin membrane surrounding the lungs. The two tubes known as bronchi evolve from the windpipe (trachea) towards the right and left lungs. Lung cancer can also largely affect these bronchi sometimes. The smaller tubes are known as bronchioles, the tiny air sacs are called alveoli, and the bronchioles and alveoli altogether make up the inside of the lungs.
Small cell lung cancer is highly metastatic and recalcitrant carcinoma. Small cells can generally have the ability to increase and affect the central regions of the brain, bones and liver along with adrenal glands. The spread of small cell lung cancer showing metastasis is treatable but a complete cure might not be possible. Pleural effusion that builds up of the fluid in the region outside the lungs leads to complexity in the normal functioning of the lungs.
The abnormal cells show metastasis evolving different cellular processes from the local invasion and intravasation into the bloodstream, survival in circulation, and extravasation, to the colonization and growth in new organ environments. Hence, different molecular programs generates through the cellular process resulting in the migration, survival, and proliferation of cancer cells 1,2. Furthermore, the molecular and cellular mechanism within the lungs allows expansion of benign cells for achieving the ability to combat the obstacles of the metastatic process.
- 1.Lambert AW, Pattabiraman DR, Weinberg RA. Emerging Biological Principles of Metastasis. Cell. Published online February 2017:670-691. doi:10.1016/j.cell.2016.11.037
- 2.Gridelli C, Rossi A, Carbone DP, et al. Non-small-cell lung cancer. Nat Rev Dis Primers. Published online May 21, 2015. doi:10.1038/nrdp.2015.9