Cells Cycle and Cancer

Differences between Normal Cells and Cancer Cells

Normal Cells will be divided in a structured way in order to produce more cells only when the body needs them where as with regards to cancer cells, more cells will be created continuously without any control. Sometimes, a mass of the tissue will be created, which is also called as tumor. Normal cells derive 20 percent of their energy from a system called ‘Glycolysia’ and 70 percent of energy from a system called ‘Kerb Cycle’. Cancer cells derive nearly 99.9 percent of energy from the system called ‘Glycolysia. Oxygen is the main source of energy for normal cells where as cancer cells will derive most of their energy without oxygen. Normal cells will have a built-in blood vessel system where as cancer cells do not. Cancer cells need amino acids to build blood vessel system. The growth of normal cells is very normal and completely in control where as cancer cells will be hyper active in their growth. Enzymes and hormones behave in a balanced manner in normal cells where as enzymes and hormones behave either hyper active or under active in cancer cells (Dingli and Nowak 2006). 

Which type of cancer shows the most aggressive growth? Explain.

Small Cell Lung Cancer (SCLC) shows most aggressive growth when compared to other dangerous cancers. The survival time for the patients who are suffering from the small cell lung cancer is nearly 3 to 4 months after diagnosis when untreated. Most of the small cell lung cancer cases are due to smoking and it is not really common in people who do not smoke. SCLC is more common in men than women and nearly 15 percent lung cancer patients are suffering for small scale lung cancer. SCLC starts at the center of the chest in the breathing tubes. Though, the cells are very small, they are very dangerous and effective in reproduction and growth. If these small cells crate a mass tissue, it will be immediately turned as a tumor. Small cell lung cancer can spread across the body very quickly. The major target areas for this kind of cancer are liver, brain and bone. Chemotherapy will be used to prolong the life of the patient that suffers from SCLC. The combination of chemotherapy and other methods can prolong the life of the patient up to 4 years. When suffering from SCLC, the chances of living for more than 5 years after the diagnosis are only 4 percent (Rosti, Bevilacqua  and  Bidoli March 2006).

Which type of tissue would have a higher mitotic index, normal tissue or cancerous tissue? Explain.

Mitotic index is used to calculate the ratio between the number of normal cells or total number of cells or between the number of cancer cells and total number of cells in the body. Mitotic index purely depends on the reproduction capability of the cells. If the reproduction capability of a particular cell is high, the mitotic index for that cell will also be very high and vice-versa. The mitotic index for cancer cells is higher than normal cells because cancer cells can reproduce their cells uncontrollably with their hyper active growth nature. The main reason behind large reproduction is high mutation of DNA in cancer cells. As per experts, the percentage normal cells dividing in normal tissue is 5 percent whereas in a cancerous lung tissue the percentage is around 25. Other reasons behind high mitotic index in cancer cells is unstructured way of cell creation, hyper active enzymes and hyper active hormones (Baak et al. (2008).

References

Baak, J. P. A.; Gudlaugsson, E.; Skaland, I.; Guo, L. H. R.; Klos, J.; Lende, T. H.; Søiland, H. V.; Janssen, E. A. M. et al. (2008). "Proliferation is the strongest prognosticator in node-negative breast cancer: Significance, error sources, alternatives and comparison with molecular prognostic markers". Breast Cancer Research and Treatment 115 (2): 241–254.

Dingli D, Nowak MA (September 2006). "Infectious Cancer Cells". Nature 443 (7107): 35–6.

Rosti, G; Bevilacqua G, Bidoli P et al. (March 2006). "Small cell lung cancer".  Annals of Oncology 17 (Suppl. 2): 5–10.