DESCRIPTION
Title of the การประดิษฐ์
RAMAN QUANTIFICATION METHOD OF CANCER-RELATED SUBSTANCE Technical Field
[0001] The การประดิษฐ์นี้ relates to a method of measuring cancer-related substances which increases in blood with the progress of cancer, ที่รวมถึง
mainly a free DNA (DNA wrapped around the histones) as a target to be
measured by Raman spectroscopy.
Background Art
[0002] A method of measuring a cancer-related substance which increases in the blood with the progress of the cancer, has hitherto been used as one of the diagnostic methods for cancer. The cancer-related substances referred to
proteins and the like, which are cancer-specific substances extracted from a
body fluid of cancer patients and are generally educed into the blood when the cancer cells are destroyed. According to the prior diagnostic methods of the cancer, it is determined that there is a possibility that the test subject or patient is suffering from cancer when more than a determined value of the cancer-related substance is found existing in the blood
[0003] Thus as the cancer-related substance educed into the blood by
destruction of the cancer cells, it is known that not only proteins but also DNA may be educed into the blood. And, when compared with the healthy subjects and cancer patients, it has been reported that the amount of the free DNA
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(ctDNA) derived from cancer cells in blood, is significantly more in those cancer patients than healthy individuals. Thus, by quantifying the free DNA of cancer cells from the body fluid such as blood, it is considered to be able to diagnose the presence of cancer . As such a method of cancer diagnosis, for example, there are proposed 1) a method of diagnosing a possibility of cancer in case of detecting 200bp or more DNA to be amplified by the polymerase chain reaction (PCR) method and the like, in the body fluid or feces discharged from the body,
and further analyzing a mutation in its DNA if necessary,(เอกสารสิทธิบัตร 1 and
2) and 2) a method of quantifying genomic DNA contained in a body fluid, and further performing DNA testing in the case of more than a predetermined value of the genomic DNA (เอกสารสิทธิบัตร 3).
[0004] Incidentally, even if the patient is diagnosed suffering from cancer, mere quantitative analysis of the DNA in body fluids is unable to to identify a cancer suffering organ . When the cancer is arising and progressing, it is known that a specific mutation of DNA occurs depending on the original cancer site. Therefore, by clarifying the type of mutation in the DNA, it may be possible to identify an organ or a cancer site where the cancer is developing. Here, as Mutations of DNA, there are listed up a point mutation of DNA, and also a structural
abnormalities such as chromosome gain or loss. For example, in about 70% of pancreatic cancer, it is known that the point mutation occurs in the K-ras gene. Also, in the analysis of loss of heterozygous, (hereinafter referred to as LOH) there have been reported the loss of specific chromosomal arms depending on each cancer type, for example, it is known that LOH is concentrated on the short arm of chromosome 3 in case of the lung cancer. Also, the amplification of long
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arm No. 8 of chromosome and the amplification of RB2 are known in the breast cancer, Therefore, in order to provide an improved method for diagnosing
cancer with high accuracy by quantifying the free DNA from cancer cells, there has been provided a method of diagnosing cancer, which ประกอบรวมด้วย a step of extracting a free DNA from plasma collected from a subject, a step of calculating the free DNA per unit volume of the extracted plasma by quantifying the free DNA, a step of comparing the calculated value of the free DNA with a second threshold value more than the first threshold value, a step of making a diagnose as follows; the subject has a high possibility of affection with cancer when the calculated value is less than the first threshold value, while some DNA from
normal cells are mixed in the plasma when the above threshold is more than the second threshold value (เอกสารสิทธิบัตร 4).
The Prior Technical Art
[0005] PATENT LITERATURE
เอกสารสิทธิบัตร 1 :US Pat. No. 6143529
เอกสารสิทธิบัตร 2 :US Pat. No. 2004 / 0259101A1
เอกสารสิทธิบัตร 3 : WO 2008/090930
เอกสารสิทธิบัตร 4 : Patent Publication No. 2011-81001
[0006] However, for example, even if we would try to quantify the free DNA
derived from cancer cells in a whole blood, whereas a trace amount of the free
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DNA is contained therein, a large amount of the DNA comes from the
lymphocytes derived from normal cells . Accordingly, even if DNA can be
directly extracted from a whole blood, it is difficult to quantify the free DNA
derived from cancer cells exactly. Therefore, for example, by using a plasma that has been separated from the whole blood, it is considered to provide a
method of quantifying the free DNA derived from the cancer cells in the plasma, but depending on the extraction method of DNA, the DNA derived from the
normal cells from such as lymphocytes might be incorporated with the free DNA derived from the cancer cells, so that not only the free DNA derived from the cancer cells but also the DNA derived from the normal cells are to be qualified together, resulting in a cause for error diagnosis of cancer. Therefore, in
proceeding an accurate diagnosis of cancer, it is important to accurately quantify the free DNA (hereinafter referred to the DNA wound around the histones in the การประดิษฐ์นี้) derived from cancer cells, so that it is necessary to provide how to extract the free DNA simply and rapidly and how to remove the DNA from normal cells in order to improve the detection accuracy of the free DNA derived from cancer, and also how to detect a trace amount of DNA precisely for the appropriate diagnosis of cancer.