Some Issues of microRNA and Cancer - Essay Example

Microrna and Cancer Review Student’s Name: Instructor’s Name: Course Code and Name: University: Date of Submission: Microrna and Cancer Review Lung cancer is one of the most persistent cancers in the world with the highest mortality rate in patients with cancer. Lung cancer affects men and women alike with the most prevalent type being non-small cell lung cancer (NSCLC). This cancer is responsible for about 80% of cancers worldwide. There is a gradual improvement in the diagnosis of the cancer so that it is notices earlier. Despite this, the life expectancy of those infected remains low with the best being a 5-year survival rate (Wang et al. 2009, p. 572). Consequently, there is the need to develop new ways of finding out the aetiology of lung cancer and to aid in more accurate prognosis of patients with lung cancer. This solution can be found in genomic medicine through the provision of newer insights into lung cancer in terms of its oncogenesis. This will in turn help in molecularly diagnosing lung cancer. Subsequently, the prognosis given will have better accuracy and give patients information that is closer to reality (Jiang & Chen 2012, p. 890). Over 50% of genes that are regulated by microRNAs are found in genomic regions associated with cancer. Consequently, microRNAs (miRNAs) can be manipulated in various ways to affect prognostic and diagnostic processes. In order to understand this, the role that micro RNA plays in the aetiology of lung cancer is a critical piece of information to be aware of. The expression patterns of microRNAs are different such that there is a progressive modification or alteration that takes place from fetal to adult and from being normal to cancerous. The discoveries from the tremendous research that have been carried out and, the possibilities of miRNA have given the cancer research world excitement. So far, it has been discovered that there are about 500 miRNA in a human genome. The research findings are mostly unaware of the functions that most of these miRNA have in the body. However, research shows that the miRNA are mostly deregulated in the presence of cancer. This information gives direction to the type of cancer that medical research needs to look for in terms of the miRNA. By identifying the presence of miRNA with aberrations in lung cancer, medical practitioners can make further developments and predictions on treatments and diagnosis. Different microRNAs have different functions. They also cater for multiple functions in the development of the lung and any case of aberrant microRNAs alter their expression and, consequently, tumorgenesis can be induced. The tumorgenesis follows an aberrant expression of microRNA. When the specific miRNA that are instrumental in lung development are affected, the result is the beginning of lung cancer. There is a very significant variation between the expression of miRNA in normal lungs and cancerous lungs (Wang et al. 2009, p. 574). This variation is additionally significant because it is important in diagnosis as well as in identifying candidates who are most likely to go through effective therapy for their lung cancer. This is because therapeutic endeavors can be targeted to specific areas in the biomarkers. Owing to the ever-developing inventory of miRNAs in humans as well as their nature to be diverse in expression patterns, it can be correctly deduced that the miRNAs are responsible for the development of numerous human organs. In addition, a number of miRNAs are potential targets. All these characteristics and features of the human miRNA also suggest that they have a significant involvement in progress that diseases take. In considering the context of mammals, the miRNAs are enriched greatly to the effect of being common to certain organs such as the lungs. This means that the miRNA have organ specific functions. Since they are mostly located in the lungs of humans, this implies that they are responsible for most of the significant functions in the lungs (Jiang & Chen 2012, p. 891). They have a very noteworthy aetiology in the human lung. The most copious expression of the miRNA let-7 is in the lungs. In an analysis carried out on animals, it was found that there are six miRNAs that are lung-specific. Nine more miRNAs are expressed in the heart and lungs. The expression of miRNA in the human lung go through evolutionary processes indicating that aberrations and modifications can take place in the miRNA, which may, in turn, result in the development of diseases like cancer. Additionally, studies show that, in the process of natural development, the evolutionary path of miRNAs may be altered. When this happens, there is poor expression of miRNA, mutation or over expression. MiRNAs are multi-functional; they are not only involved in the controlling of expression witnessed in tumor suppressors and protein-coding oncogenes. They are additionally involved in the direct suppression of tumors and oncogenes (Blenkiron & Miska 2007, p. 107). This implies that any mutation in the miRNA leaves the lung susceptible to cancerous tumors. This also implies that the lung is most susceptible and that the miRNA are there to suppress the tumors and oncogenes that may cause lung cancer. There is a strong connection between the changed expression of miRNA and cancer development (Wang et al. 2009, p. 574). The aberrations can be present in few, many, or even just one miRNA. In studying the expression of miRNA in human lung cancer or tumor, it has been discovered that the expression has a close link to the progression, diagnosis, prognosis, response to therapy and treatment and staging of the disease (Nair, Maeda & Ioannidis 2012, p. 3). About 123 miRNA can be potentially linked to lung cancer. This was found out through the comparison of miRNA from a cancerous lung with the non-cancerous lung tissues that are around them. Additional tests demonstrated, through ambions, that three miRNA that are significantly in higher expression than others are. In addition, six more are expressed at lower levels in the situation of lung cancer. When an individual has lung cancer, there are certain areas in the lung that are amplified or deleted. MiR-205 and miR-21 are common in the lung areas that are amplified while the miR-126 is in the lungs that are deleted. The following table shows how miRNA dysregulation occurs in the development of the lung as well as lung cancer. Normal and cancer lung miRNA are expressed differently (Jiang & Chen 2012, p. 892). NSCLC and SCLC, other tumors, solid tumors and lung cancer are different. These differences appear in tumors, serum and plasma of those affected (Iorio & Croce 2012, p. 150). The miRNAs found in the serum are resistant to digestion of RNase. This implies that they are the most appropriate for use in as clinical biomarkers. Consequently, the most effective measuring technique tumor-derived miRNA is using blood-based methods. This methodology has the potential of being more effective than other methods of cancer detection. The expression of certain individual miRNA is considered to be more effective in prognosis than other miRNA expressions (Nair, Maeda & Ioannidis 2012, p. 2). Human lung cancer has been found to go through potentially curative resection. This can be grouped into two within the let-7 miRNA. If there is a decrease in the let-7 miRNA, the prognosis associated with it is a shorter survival period post-operation. However, this also depends on the stage of the disease. This information is helpful in prognosis as well as in determining the course of treatment. When it comes to prognosis, a doctor can use the symptom of a decreased number or level of let -7 miRNA to deliver an accurate prognosis to a post-operation patient (Jiang & Chen 2012, p. 893). In addition, if the doctor notices this symptom before pursuing any treatment options, he can make it a point to exclude surgery/ operation. Progression is also associated with more decrease of the let-7 miRNA. The following diagram gives an overview of cancers that have been identified and their association with certain miRNA. Lung cancer is indicated by the purple dot. The miRNA are identified at specific chromosomes positions. The miRNA include in this diagram are those implicated in cancers. Source: Blenkiron and Miska 2007, R107 The mir-17-92 is one of the most studies miRNA for oncogenic potential. Jowever, let 7 miRNA are the most studies in general lung tumor suppressor genes (Wang et al. 2009, p. 584). However, it provides prospects for therapeutic strategies when it comes to curing lung cancer. This is because it is a tumor suppressor. It is also down regulated in the presence of cancerous cells and tissues. Let-7 is more significant in lung cancer because it presents in a significant decrease in individuals with lung cancer, while the decrease if not so notable in other cancers, including breast and colon cancer (Wang et al. 2009, p. 585). Consequently, its aetiology is important in lung cancer more than other cancers. Down regulation or decrease of let-7 has an association with less chances of survival. Sometimes the let-7 gain effectiveness through pairing with 3’UTR of the miRNA they are targeting. This is because the 3’UTR have locations that complement let-7 (Blenkiron & Miska 2007, R107). This information shows that let-7 has an impact as an anti-cancer accelerator or trigger. Immortalized lung epithelial cells have mature forms of let-7. Let-7 is instrumental angiogenesis. The following diagram shows the impact that let-87 has in proliferating A549 lung cancer. Source: Wang et al. 2009, p. 586 The let-7 family has associations with certain mapped areas in the human chromosome of an individual with lung cancer. The position and number of let-7 miRNA in the human chromosome of those with lungs cancer differs significantly from those without lung cancer. This is because there are certain intervals in the chromosome that are deleted owing to the presence of cancerous tissues (Wang et al. 2009, p. 586). Subsequently, let-7 has a potential purpose in tumorigenesis. In conclusion, the importance of miRNA in the biology of human organ development and disease is significant, and its implications in detection, diagnostic, prognostic and treatment capacities, are as vital. The particular implication in cancer research presents overwhelming possibilities (Blenkiron & Miska 2007, R107). The available research shows that miRNA are important in diagnosing cancer. However, this conclusion is often arrived at through the process of comparing miRNA in lung tissue with cancer against miRNA in lung tissue without cancer. There is the need to develop more accurate and reliable ways to carry out the same tests on tissue in relation or in comparison to those expected in cancerous tissues (Jiang & Chen 2012, p. 894). miRNA expression in specific tumors should be identified so that this information can provide a reference point for detecting and diagnosing other expressions of miRNA without the need to compare the result to other unaffected tissues. This will be important in getting rid of inconsistencies that may arise as a consequence of the varying results that may be gained from using the results of individuals whose cancers have been customized to their bodies. The availability of information on miRNA expression with clinical parameters or tumor subtypes is important in the formulation of baseline diagnostic data. This will also be helpful in diagnosing cancer at earlier stages. List of References Blenkiron, C & Miska, EA 2007, “miRNAs in cancer: approaches, aetiology, diagnostics and therapy,” Human molecular genetics, vol.16, no. 1, pp. R106-R113 Iorio, MV & Croce, CM 2012, “MicroRNA dysregulation in cancer: diagnostics, monitoring and therapeutics. A comp,rehensive review,” Embo molecular biology, vol. 4, no. 3, pp. 143-159. Jiang, YW & Chen, LA 2012, “microRNAs as tumor inhibitors, oncogenes, biomarkers for drug efficacy and outcome predictors in lung cancer (review),” molecular medicine report, vol. 5, no. 4, pp. 890-894. Nair, VS, Maeda, LS & Ioannidis, JP 2012, “Clinical Outcome Prediction by MicroRNAs in Human Cancer: A Systematic Review,” Journal of national cancer institute, pubmed Wang, QZ, Xu, W, Habib, N & Xu, R 2009, “Potential Uses of MicroRNA in Lung Cancer Diagnosis, Prognosis, and Therapy,” Current Cancer Drug Targets, vol. 9, no. 4, pp. 572-594. Read More