Essay Example on Cancer arise due to the sequential variation of Genes









Introduction Cancer arise due to the sequential variation of genes that control cell growth Leon and his colleagues suggested that the ct DNA circulating tumor DNA have found in increased concentration in cancer patients as compared to those patients who are non malignant They have found that the normal patients have DNA concentration 13ng ml while cancer patients have 180 ng ml This increasing amount of ct DNA is due to the lack of proper treatment Experiment with many kinds of malignancies like leukaemia lung gastrointestinal and breast cancer they have found that the ct DNA bearing massive quantity of tumor cells when this DNA was extracted and purified it is also determine that cancer cells have biophysical properties like decrease strand stability Due to this property expose to various carcinogens separation of DNA strand can be determine by increase in hyperchromicity so cancer cell DNA expose at low temperature Moreover stimulation of DNA synthesis in vitro indicated that the increase in samples of DNA from cancer patients having 64 to 300 and no increase have seen in healthy donors they indicated that the DNA from the plasma of cancer patients showing a hyperchromic effects at room temperature after adding carcinogens other control DNA showing hyperchromic effects after the addition of KOH 

These experiments showed that the ct DNA is present in the plasma of cancer patients Further to showing the effect of ct DNA in the development of PCR late 1980's the first mutational experiment was performed on plasma DNA concentrated by oncogenes like K ras and N ras known to be mutated in many types of cancers K ras gene have point mutation have 90 of pancreatic and 50 of colorectal carcinomas and N ras gene have 40 of myloblastic leukemia Recent study showed that tha DNA methylation also determine in the serum of cancer patients Another Microsatellite DNA alteration in plasma of head lung and renal cancer have also studied as clonal markers for human cancer and these microsatellite alteration are basically related to the lung cancer Sidranks et al 1935 The use of microsatellite in the plasma of cancer cell as a tumor marker depend on the type of cancer Although it is obvious that DNA circulates freely in blood plasma each in disease and in fitness the supply of this DNA stays enigmatic it can be presumed that circulating DNA in healthful subjects derives from lymphocytes or other nucleated cells yet it isn t always regarded why cancer sufferers have such large quantities of plasma DNA nowhere this genetic material derives from 

As with everyday subjects a proportion appears to originate from lymphocytes considering the fact that wild type DNA has been detected in the plasma of all most cancers sufferers studied to date however a full size proportion of plasma DNA in most cancers patients derive from tumour cells This latter idea is supported through each quantitative and qualitative observations plasma DNA stages aren t best greater in cancer patients than in everyday subjects but additionally correlate inversely with final results and generally tend to fall with effective treatment in addition the ability to detect in plasma DNA suggests that mutant DNA is the major subtype in as a minimum some cancer patients the most not unusual speculation superior for circulating DNA within the plasma of most cancers patients is that it's far due to the lysis of circulating most cancers cells or micrometastases shed by the tumour that is certainly not the case considering the fact that there aren't sufficient circulating cells to justify the amount of DNA located in the plasma sorenson calculated that during relation to the quantity of DNA he found in the plasma of pancreatic cancer patients there could must be one thousand cancer cells per ml which is far more than has ever been found using another

 DNA extraction process boehringer columns which yields ten times greater dna than the technique used by sorenson qiagen kit it might need to be assumed that 10000 tumour cells in keeping with ml are circulating in the blood circulation now within the case of colorectal patients no ras mutations have been discovered inside the cells of the ficoll layer in which micrometastatic cells must be discovered moreover the same mononuclear cells which must encompass circulating tumor cells if there are any have been used as control of normality in all microsatellite evaluation it as a result appears that tumour DNA shed inside the blood flow might be due either to DNA leakage as a result of tumour necrosis or apoptosis or to a new mechanism of active launch tumour necrosis has been postulated when you consider that better quantities of DNA had been found in plasma of patients with big tumours or with advanced diseases with metastases although it should be reminded that plasma tumour DNA is also discovered in early degrees an argument against necrosis is that after radiation remedy the plasma 

DNA degrees decreased up to 90 whereas one may assume an preliminary plasma DNA surge following radiotherapy if necrosis turned into the predominant pathway for DNA release it could be hypothesized that the tumour actively releases dna into the blood circulation if one cannot affirm that the circulating tumour dna proceeds of the same mechanism as found in vitro in which lymphocytes or entire organs spontaneously release dna it remains possible and plausible that both phenomena are associated in the end out of doors the field of oncology plasma DNA can be used inside the future for the prenatal detection of genetic illnesses considering that fetal DNA has been detected in maternal plasma or serum allowing intercourse willpower furthermore the presence of donor DNA in plasma of graft recipient opens new opportunities for post graft follow up

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