Biomedical science involves using a range of laboratory techniques to diagnose and find treatments for various diseases. In this essay we will focus on the role that biomedical science plays in diagnosing various types of cancers. The different approaches in biomedical cancer diagnosis that will be covered are: biomarkers (i.e., miRNA), biopsies (i.e., liquid biopsies), blood tests and histology image analysis.
Biomarkers are found in blood, tissues as well as other fluids in the body. These are biological molecules that can be used identify complications and diseases that arise in the body, these can be both abnormal and normal. There are two functions of biomarkers: for exposure and diagnosis of diseases. Cancer biomarkers are essential for diagnosing the presence of cancer, they do this by detecting molecules that are being secreted by cancerous tumors as well as a response that the body makes due to the presence of the disease. An example of a cancer biomarker is miRNA. miRNAs are regulators of gene expression and therefore can be compared to with the progression of cancer, this biomarker detects cancerous molecules on a genetic level, through its gene expression. Gene expression is regulated by miRNA, this can closely be linked with the staging of cancer diagnosis as it has been found by Dr Rosenfeld that scientists are able to locate the origin for cancers that had an unknown primary origin by using miRNA expression and profiling (B. Mansoori et al., 2010). The use of miRNA as a biomarker can be applied to cancer diagnosis as it can differentiate between normal and malignant tissues and the subtypes of a specific cancer, through a genetic approach on the regulation of gene expression controlled by miRNA. Expressed miRNA profiles have modified and altered a vast range of human cancers in comparison to its corresponding normal tissues and subtypes of a specific type of cancer. For example, in the brain high levels of miR-21 was expressed in the glioblastoma whereas on the contrary a low basal level in normal brain cells (Chan JA et al., 2005). This indicates that the miR-21 can be used as a diagnostic marker for the glioblastoma in aiding scientists to find the point in which genes were not expressed correctly. Focusing on the expression of genes can assist scientist identify trends and patterns in regards of the changes that is made when the genes are being expressed. This provides scientists with the ability identify similar genes for a specific type of cancer and its subtypes and how these genes differ amongst the different subtypes of a cancer or the severity of a particular cancer in the diagnostic stages.
Biomarkers can be used with biopsies tests such as a liquid biopsy to diagnose and detect cancer. A biopsy can help scientists tell where the cancer first originated and the specific type of cancer. Liquid biopsies involve sampling and analyzing non-solid biological components such as DNA found in the blood extracted from tumors. When cancer is detected at an earlier stage, there is an increase in survival rates in patients. Therefore, it is important to diagnose cancer at an early stage but accurately. The way in which liquid biopsies helps improve accuracy is through the method of extracting blood directly from the site of the tumor, by doing so there is a higher chance that cancerous molecules can be identified when being examined making the outcome diagnosis results more precise. Using both biopsies with biomarkers helps identify where the change in the gene occurred due to the protein marker that is attached to the DNA in the blood plasma sample. In a study circulating tumor DNA was used as a liquid biopsy, where cfDNA was used as the diagnostic biomarker tool. It was found that patients with higher quantities cfDNA counts in their blood displayed the presence of cancer and this molecule was more present in cancer patients (Sozzi et al., 2003). An advantage for using this quantitative method is that both progression and potential recurrence of the disease can be told in diagnosis when identifying the surrogate molecules that indicate cancer. Whereas as mentioned before the miRNA biomarker focuses heavily on changes of the genome, liquid biopsies on the other hand are more applicable to a wider range of patients and individuals as it does not rely on genetic changes but more so on the cancerous content present in blood samples. More advantages of using these methods together: 1) results are obtained faster and in a less invasive manner; 2) not only can it tell where the cancer originated from, but it can help grade the cancer by being able to tell the severity of the cancer at the early diagnosis stage.
Other blood tests can help scientists see different molecules to diagnose cancer such as the high levels of the antigen CA-125 looked for in ovarian cancer patients. Other molecules that can be detected in blood for cancer diagnostic which includes hormones and antibodies however high levels of molecules such as CA-125 cannot tell doctors for certain for the presence of ovarian cancers, therefore other tests can also be taken. Despite extracting substances from patients creating different types of images to see the histological structures that is associated with cancer is another tool used for cancer diagnosis. Biomedical scientists use different forms of imaging such as histology image analysis for carcinoma diagnosis and classification. Histology image analysis a computer aided method has replaced ordinary histology images produced. This makes it more accurate in diagnosing cancer as the quality of the structures that are being seen making it easier for scientists to interpret the structures of the healthy and malignant tissues. Through the staining, different structures are seen under the microscope and the images being made from a low magnification, this in which helps analyze specimen at tissue level making it easier for scientist to grade and classify the cancer.
Biomedical science plays a crucial role in the diagnosis of cancer through different methods of diagnostic. This essay has shown how biomedical science helps aid in not only detecting cancers but grading and classifying them by finding where the origin of the cancer through biological markers, samples, and imaging in the process of diagnosis. Although methods such as histology image analysis being a continuous promising tool for carcinoma diagnosis using the method alone can have limitations as in lung cancer different histological structures that have a mixture of cells in the same tumor, makes it difficult to differentiate the structures on a molecular level by, i.e., gene expression picked up by the miRNA biomarker. Using sample analysis and imaging can not only help see how the physiological structures differ when they are malignant but also through sampling, they tell biomedical scientists what is going on molecularly and why. Making these approaches not only a crucial tool for diagnosis but also the depth of the diagnosis which improves treatment options when specific cancer subtypes are identified and graded making it play an important role in carcinoma diagnosis.