With the rapid development of biotechnology in the medical field and a deeper understanding of the onset of tumors at the cellular level, tumor therapy has gradually shifted from the era of cytotoxic drug therapy in pre-genomics to a new era of targeted therapy in the post-genome.

Over the past two years, genetic testing has become a standard measure of cancer diagnosis and treatment. Basically, all cancer patients have their own set of genetic test reports. . It must be said that the era of individualized diagnosis and treatment of the patient's program has arrived. For example, cancer patients who perform a full genetic test as well as pathological diagnostics find mutations for chemotherapy, target targeting, immunotherapy programs, and family cancer risk assessment patients.

Today, the Cancer Oncology Society has a comprehensive science for cancer patients, and cancer patients should read this article carefully before doing genetic testing!

Summer :

1. What is cancer gene? 

2. What is Cancer Genetic Testing? 

3. What is targeted therapy based on genetic testing? 

4. What genes can detect various types of cancer? 

5. The advantages and disadvantages of various cancer gene detection technologies are great! 

6. How can I choose a reliable genetic testing agency? 

7. Which genetic testing program to choose? Is the whole gene still hot? 

8. Do all cancer patients need genetic testing? 

9. What kind of sample is better for genetic testing? Tissue, chest and revenge or blood? 

10. How much does cancer genetic testing cost? 

First, what is cancer gene?

uman DNA is the carrier of genetic material, and the gene is a genuinely meaningful DNA fragment. The reason cancer patients suffer from tumors is because of the strange mutations that cause many deleterious mutations in the body to accumulate in the final analysis and ultimately cause cancer.

Many kinds of genetic modifications can occur in cancer cells. The main types are: 

DNA-based changes

1) base substitution 

2) Insert or omit 

3) Number of Copies 

4) relocation 

mRNA-based changes 

mRNA may or may not be present in cancer. When present, sometimes "overexpression" (the expression level is higher than normal). It is usually easier to detect mutations at the DNA level, and more accurate detection at the mRNA level is more accurate if the detection of fusion mutations in ALK, ROS, and NTRK over the last two years is more accurate.

Protein-based changes

Proteins can be present or absent in cancer. Immunohistochemistry (IHC) can be used to detect mutations or deletions in proteins. Detection of protein levels during clinical drug use is also important for drug guidance. For example, the selection of EGFR-targeted drugs in lung cancer is based on a sensitivity test at the DNA level rather than protein-level immunohistochemistry (IHC). However, recent studies have shown that higher levels of EGFR expression measured using immunotherapy (IHC) are expected to be associated with chemotherapy compared to chemotherapy alone, in response to cetuximab (an anti-EGFR antibody).

Second, what is cancer gene testing?

We know that cancer is a genetically vulnerable disease and that there is an inseparable relationship with genetic mutations, and to a certain extent these genes also determine the growth and division of cancer cells. I will inherit. You can now test the genetic map of this tumor to see what mutations have occurred and this process is called genetic testing.

Oncogene genetic tests range from simple to complex. The simplest test detects only one type of mutation in the gene. For example, a search for a particular T-to-A substitution mutation is only found at BRAF position c.1799. 

In contrast, the most complex tests can detect both major types of genetic changes, including simultaneous replacement, replication, insertion, deletion, insertion, gene copy number change, and structural modification including translocation and reversal.

Third, What is the target treatment based on genetic testing?

Genetic testing in the actual course of treatment can help your doctor develop the best treatments. For example, some people with lung cancer can use genetic testing to detect EGFR in cancer cells. Once a mutation is found, it can be treated with the target drug. As another example, there are some tumors that are very difficult to diagnose and require you to rely on specific genetic changes to aid diagnosis. For example, many breeds are as long as a long, flat shuttle, and the diagnosis of soft tissue sarcoma is impossible if genetic testing finds ASPL-TFE3 fusion genes.

Using a variety of methods to identify these mutated genes, careful analysis can aid in clinical diagnosis, treatment option guidance, disease recurrence and drug resistance monitoring, and survival prediction. 

4. What genes should be actually detected in various types of cancer?

Generally speaking, all cancer patients are eligible for genetic testing, but in a narrow sense are suitable for guidance, other diseases, different stages, different purposes, different patients, different genetic tests.

Prior to the establishment of the National Health and Health Committee 's Guidelines for Clinical Application of New Anticancer Drugs (2018 edition), "it is clear: Clinical applications of anticancer drugs for use after histopathological diagnosis or genetic testing. , But the guideline principle covers only the targeted target drug in Korea and the listing of the global oncology physician network and overseas new drugs is a systematic list . 

Primary peritoneal carcinoma mutation targets and related target drugs 

Melanoma mutation targets and related target drugs 

Fifth, the advantages and disadvantages of various cancer gene detection technologies are great! 

There are many techniques for gene testing, and lay people can not accurately identify them. It is clear to everyone that the advantages and disadvantages of the 13 types of gene detection techniques enumerated by the Global Oncologist Network are compared. 

1. Allele-specific PCR

Advantages: Sensitivity - 1-5% mutation is required. No special equipment is required. 

Disadvantages: Target specificity, other mutations that may be present in tumor DNA can not be detected. 

2. Sodium dideoxy sequencing 

Advantages: You can discover various unknown mutations. Once the RNA of the fusion progenitor is extracted from the initial sample, it can be used to detect gene fusion. No special equipment is required. 

Cons: labor intensity, the need for mutant DNA is 20-25%. No change in exon or gene copy number can be detected. 

3. Pyrosequencing 

Advantages: Rapid and sensitive detection of 5% levels of mutant DNA. 

Disadvantages: Pyrosequencing tools are needed and there are limitations to the types of mutations that can be found in tumor DNA. 

4, mass analysis

Advantages: 5-10% reliable detection of sensitive, mutant DNA, multiple gene testing. 

Disadvantages: We need a mass spectrometer that can not detect SNV specificity and other mutations in tumor DNA that may be present. 

5, single basic extension measurement 

Advantages: Sensitive and reliable detection of mutant DNA (5-10% if present), multiple genetic testing. No special equipment is required. 

Disadvantages: SNV is specific and can not detect other mutations that may be present in tumor DNA. 

6. Multiple ligation dependent probe amplification - MLPA 

Advantages: Detect multiple mutations simultaneously and quickly. No special equipment is required. A target SNV of 10% can be detected. 

Disadvantages: Mutant DNA must be present at levels of 20-40% in order to detect mutations in exon or gene copy number. Targeted SNV and exon and gene copy number variants are all specific and can not detect other mutations in tumor DNA. This kit may not be suitable for your gene of interest or mutation. Fresh frozen tissue detection is superior to paraffin embedded tissue for DNA extraction. 

7. Fluorescence in situ hybridization - FISH

Advantages: The ability to easily detect undetectable gene copy number changes and targeted SVs in other ways, and cell-based imaging can detect events in a small number of cells. 

Disadvantages: An undyed portion of paraffin embedded tissue is required, and most types of mutations in solid tumors can not be detected. 

8, Next Generation Sequencing - Amplification Capture 

Advantages: Simultaneous detection of more complex mutations, including repetition, insertion, deletion and insertion in a single gene and multiple gene mutations in a single analysis, requires a small amount of DNA. When sequencing with a high "coverage depth" (1000x coverage), the assay is sensitive to low-presence mutation detection. 

Disadvantages: It is costly and requires a completely different DNA preparation method than other molecular detection methods. The gene copy number is changed and SV can not be found. 

9, Next Generation Sequencing - Hybrid Capture 

Advantages: The ability to detect multiple gene substitutions, repetitions, insertions, deletions, insertions, and exon and gene copy number changes simultaneously in a single analysis. Probes can also be designed to capture selective disruption breakpoints in genes that are frequently relocated (eg, one of the Foundations TM. 

Disadvantages: Costly, requires a completely different approach to DNA preparation traditionally used for other molecular mutation tests, requires more tumor tissue, and requires complex bioinformatics. 

10. Next Generation Sequencing - Full Exome Sequencing 

Pros: Medium-scale inclusiveness. In the same analysis, substitution, repetition, insertion, deletion, insertion, and exon and gene copy number changes in many genes can be detected at the same time. 

Disadvantages: Costly, requires completely different DNA preparation methods traditionally used in other molecular mutation detection techniques, requires more tumor tissue, and requires complex bioinformatics. 

11, next generation sequencing - whole genome sequencing 

Pros: The most comprehensive. Replace, duplicate, insert, delete, insert, change gene and exon copy number, detect chromosome reversal and translocation in whole genome simultaneously. 

Disadvantages: Costly, low yield, completely different from traditional DNA preparation methods used in most mutation detection techniques, requires more tumor tissue, requires complex bioinformatics, and has a large computational need for data storage and processing. 

12. Digital PCR - ddPCR 

Advantages: High sensitivity and specificity, relatively inexpensive. 

Disadvantages: Only known target mutations can be detected, limited to the type of mutation detected and only a limited number of mutations per assay can be detected. 

13, BEAMING technology 

Advantages: High sensitivity and specificity 

Disadvantages: Only known target mutations can be detected, limited to the type of mutation detected and only a limited number of mutations per assay can be detected.