Cancer ,Cancer Genes and Growth factors are Interrelated with one another. The extent of spread depends on various factors such as the carcinogen , the body defense against mutations , the invasiveness ,metastasis ,the exposure time and amount to which the cell is being exposed .These are many physical, chemical and biological causes which I am not going to discuss in this article. This article is mainly, is to understand the Carcinogenesis and its associated factors.
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What is cancer? and how does it happen ? Who prevents it from happening? Some of these questions often come in our mind. As we already know that cancer is an uncontrolled proliferation or growth of our cells .The carcinogens are the cause of it and it is interdependent upon the above factors. The carcinogens - Smokes, sunburns, viruses and few organisms, chemical burns and even mechanical trauma can lead to Carcinoma. These agents Damages or alters the DNA of a cell, which is referred to as mutation. This is why some often say that “Cancer is truly a disease of genome “. The initiation which helps to activate the process of mutation and finally damage the DNA are all dependent upon the carcinogenic agent and its virulence and exposure. As for example – Phorbol esters promotes the activation of protein Kinase C which indirectly exerts a variety of effects upon the cell.
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The few main mechanisms of these genes to oncogenesis are – Promoters and Enhancer insertion; Chromosomal trans-location; Gene Amplification and; Point mutation.
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TSG or tumor suppressor gene plays a key role in prevention of cancer. Oncogenes accelerate the carcinogenesis process while the TSG decelerates the same.The TSG is one which keeps a control over the initiation of the mutation along with some other factors.
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Two of the most important tumor suppressor genes are RB1 and p53 (Nuclear phosopho-protein), which affects the transcription of the genes involved in regulating the cell cycle.
As for Example: Colo-rectal Cancer ( A genetic Model ) involves the interplay of TSG and
ras oncogenes. ; Mutation is mismatched repair genes have been associated with hereditary non-polyposis colon cancer, while loss of responsiveness to the growth inhibitory for the growth of the type of tumor.
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A number if cancer susceptibility genes isolated includes RB1, p53 and BRCA1.
Therefore we can say that for carcinogenesis the balance between the DNA repair system and Activation Oncogenes might be the cause of Initiation of carcinogenesis.
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We often get big names in the reports of diagnosis like- Carcinoembryonic Antigens (colon , lungs, breast , pancrease ); Alpha-Fetoprotein (liver , germ cell ) ; Human Chorionic Gonadotropin ( Trophoblast , Germ cells ) ; Calcitonin (thyroid ) Prostatic acid phosphatase ( Prostate ) Etc.. But what are these ?? These are Tumor markers those help in detection and in deciding the treatment plan for a particular kind of tumor. Nuclear scanning is the technique to locate the mass. While Staging helps to define the extent and its spread .
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The Carcinogens or the oncogens helps in the initiation of the mutation process. The surface of the malignant cell has many changes like – alteration in the permeability of the cell and transport properties; Diminished adhesion ,Increased agglutinability by many lecitins ; Enzyme activities ; loss of certain antigens ;alteration of olligo-saccharide chains of glyco-protein; and changes of glyco-lipid.
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All these factors together affects the growth of the malignant cell and hence is the key to understand the process of carcinogenesis in a better way.
