A Small-Cell Lung Cancer Genome with Complex Signatures of Tobacco Exposure

Increased attention has been placed on lung cancer as the annual death rate from lung cancer continues to rise globally. Governments and health sectors around the world work side by side as they attempt to combat this serious problem. Recent findings indicate that tobacco smoke causes cells to mutate resulting in lung cancer. An article by Pleasance et al., which was published in the January 2010 issue of Nature, relates the use of massively parallel sequencing technology to sequence a small-cell lung cancer cell line in an attempt to gain insight on the mutation process caused by tobacco smoking. The purpose of this paper is to review the study presented in said article by considering several factors, such as the objectives of the article the useful features of the article and the broader implication of the research discussed in the article.

Keywords lung cancer, mutation, tobacco smoking, sequencing,  molecular biology, small-cell lung cancer, genome.

I. Introduction
According to Hong (National Foundation for Cancer Research, n.d.), the leading
cause of cancer-related death in both men and women is lung cancer. The severity of the lung-cancer related problem can be observed in the U.S., as reports indicate that an estimated 219,440 new cases and 159,390 deaths from lung cancer are expected in 2009.

In view of this, the article by Pleasance et al. (2010) discusses a research conducted to determine the effects of tobacco smoking in the activation of cancer genome resulting in lung cancer. A genome can be defined as the total amount of genetic information in the chromosomes of an organism, including its genes and deoxyribonucleic acid (DNA) sequences. In the research, the authors attempted to determine the cancer-causing mutation of a human DNA caused by tobacco smoke.

II. Method
In the article, the researchers analyzed the mutation stages of the cancer genome by applying a method called sequencing, which is the process of determining the precise sequence of nucleotides, or group of molecules, in a sample DNA. To get better results, the researchers used a massively parallel sequencing technology in the sequencing of NCI-H209, which is a small-cell lung cancer (SCLC) cell line. The research derived cancerous cells that was transmitted to the bone marrow of a 55-year-old male with SCLC. The cells were obtained before the man underwent chemotherapy. Findings indicate that more than sixty cancer-causing chemicals are found in tobacco smoke causing cells to mutate. According to the researchers, the use of massively parallel sequencing method allows biochemists to learn more about genome-wide mutation.

III. Results
The article highlights the use of massively parallel sequencing method in order to identify the carcinogens, or cancer-causing chemicals, found in cigarette smoke. Moreover, the method was able to recognize the point wherein the cell s attempts to repair DNA damage was partially successful. The study found an unknown gene expression-linked repair pathway that operates on both transcribed and non-transcribed DNA strands implying that at least two separate DNA repair pathways have been enlisted to protect the NCI-H209 genome. According to the authors, the findings illustrate the purpose of the research which is to highlight the potential of DNA sequencing in making breakthrough advances in cancer development research .

IV. Discussion
The introduction of the Pleasance et al. article provides a background on the severity of the health problem being faced globally in relation to smoking as they presents brief stastistical data on the rising number of lung cancer cases worldwide. The authors were also able to highlight the lung cancer-causing risks associated with direct tobacco smoking and with indirect exposure to tobacco smoke. The article s introduction also stresses the importance of having a comprehensive understanding of the mutation patterns in human cancer as this could lead to further advances in molecular biology.

As the rest of the article progresses, it becomes confusing as, what is typical in a scientific journal, highly technical terms are being used throughout the article. The article provides an attention-grabbing idea, but an average person with no extensive background in the field of molecular-scale biological sciences will find it difficult to understand.

The research findings discussed in the article is indeed a breakthrough in terms of cancer research. One of the strong aspects of the study is that it focused equally on various components such as the pathogenesis of cancer, the advent and use of massively parallel sequencing technologies and genome mutation. The broader implication of this study is that, with the additional scientific knowledge brought about by this study s findings, it will serve as a motivating factor for next-generation scientists to produce more findings that can save more lives.

In addition to the findings mentioned in the abovementioned article, another related study has been conducted by Waun Ki Hong (National Foundation for Cancer Research, n.d.) as, in a somewhat similar manner to Pleasance et al s approach, his team has developed individualized targeted therapies for cancer treatment by targeting specific molecular abnormalities in individual patients.

V. Summary and Conclusion
The yearly number of lung cancer-related deaths globally continues to grow at an alarming rate. Reports indicate that lung cancer is now the most common type of cancer in the world, with an estimated total number of 1.2 million cases occurring annually (cited in IARC, 2004). This is an indication that the problem of lung cancer is getting out of control and needs to be addressed immediately. The research findings presented in the article  reviewed is another step to solving the rising cancer mortality problem. As the article points out, cigarette smokers are not the only casualties of lung cancer but also non-smokers who may be exposed to tobacco smoke.

In conclusion, it is interesting to note that the field of biological science, although wide-ranged, is interconnected in every way, as we see that each field has a crucial role to play in its aim for the advancement of science and the betterment of people s lives. The article is an excellent example of the importance of pushing one s self to further heights and the continuation of acquiring new knowledge as we go through our everyday life.


Post a Comment