As DNA damages are mainly involved in the formation of primary tumor but somehow it diverts towards the development of melignant tumor, which leads to metastasis property. What is that mechanism or pathway in which DNA damages are involved for the transformation of primary tumor into secondary tumor.
Hello reena in context to your question, Cancer obviously not always resulted due to the DNA damage. In the meantime the DNA damage can leads to the mutation which turns a normal cell into the immortal cell.
Good question Reena,
Cancer is an uncontrolled cell division. Cell division is controlled by two types of genes: The oncogenes which induce cell division and the suppressor genes which stop division. These genes working in harmony are responsible for regular cell division, however a mutation in onco and/or suppressor genes can lead to uncontrolled division.
Actually the immune system recognizes the tumor at its primary stage and kills tumor. Example, beauty spots. But it happens that at a later time the tumor can reestablish several phases (the three Es: Elimination, Equilibrium and Escape) of cell division at the point that it escapes from the immune system. This mechanism was investigated and it seems that there are different strategies to escape the immune system like mutations in tumor antigens and their low expression. Here are some articles with more details.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2265921/
http://www.jleukbio.org/content/71/6/907.long
Best,
Dear Brahim,
thank you for your comment and would you please inform me what about another genes like DNA repair gene or metabolic gene..
actually i'm studying two polemorphism in AHR gene and CYP1A1 gene that be association with breast cancer in epidemiological studies and i have confused when i writing my thesis it's not clear to me how i establish a map to write the literature
Thanks a lot
Hello reena in context to your question, Cancer obviously not always resulted due to the DNA damage. In the meantime the DNA damage can leads to the mutation which turns a normal cell into the immortal cell.
DNA damage provides risk factors for cancer development. However, in cancer development requires mutation in key cancer related genes; genes that play a role in regulating apoptosis, cell cycle regulation, division, proliferation. Cancer can be seen as a disease of the cell cycle or genome. Cancer development requires mutations in 2 sets of genes; mutations in proto-oncogenes that give cancer like properies and mutations in tumor suppressor genes that represents barriers to cancer. Mutation in protein coding for RAS and p53 are seen in over 50 percent of cancers.
Hi Rohan,
Cell division is not controlled by oncogene and suppressor gene but by oncogenes and suppressors genes. You have to know that mutation percentage in these genes differ in every type of cancer. "For example" you can say p53 mutation is not the cause of X cancer but it can be the cause of Y cancer because it's "as example" 40% mutant in Y rather than 5% in X and this rule is appllied for all onco and suppressor genes.
@Brahim,
Rohans argument is valid. Multiple mutations must occur for carcinogenesis to proceed. Protective mechanisms in the cell act to disrupt the cell cycle due to alterations to the genome that lead can to a cancer phenotype. Even mutations in tumor suppressor genes in 1 allele will not cause uncontrolled cellular proliferation.
Shifting from primary tumor to secondary tumor and finally metastasis in majority cases is relaid on presence of Cancer Stem Cells. in this case , the mechanisms of DNA damaging and its repairing in CSC is 10 fold compared to cancer cells without CSC, meaning that DNA damaging have no any effects on this types of cells. In addition to this it's well understood that CSC are cardinal factors of metastasis even applying DNA damage-based drugs.
- Badges
- Science topic
- Similar topics
- Medicine
- Oncology
- Cancer Research